as used herein , the term “ monoclonal antibody ” means an antibody composition recognizing a discrete antigen determinant . it is not intended to be limited with regard to the source of the antibody or the manner in which it is made . the term antibody is also intended to encompass whole antibodies , biologically functional fragments thereof , chimeric and humanized antibodies comprising portions from more than one species , or other molecules whose binding properties are derived from antibody - like high affinity binding sites . in this instance , monoclonal antibodies have been produced by hybridomas . however , monoclonal fab fragments and igg fragments can also be produced by other methods , for example by using bacteriophage to display and select polypeptide chains expressed from a v - gene library or genetic engineering . biologically functional antibody fragments are those fragments sufficient for binding to the desired stimulant drug , such as fab , fv , f ( ab ′) 2 , and sfv ( single - chain antigen - binding protein ) fragments . one can choose among these or whole antibodies for the properties appropriate to a particular method . the chimeric antibodies can comprise proteins derived from two different species . the portions derived from two different species can be joined together chemically by conventional techniques or can be prepared as a single contiguous protein using genetic engineering techniques ( see e . g . cabilly et al ., u . s . pat . no . 4 , 816 , 567 ; neuberger et al ., wo 86 / 01533 and winter , ep 0 , 239 , 400 ). such engineered antibodies can be , for instance , a chimeric antibody comprising murine variable regions and human constant regions , or complementarity determining regions ( cdr )- grafted antibodies ( tempest et al ., biotechnology 9 : 266 - 271 , 1991 ). the constant region domains can be chosen to have an isotype most suitable for the intended application of the antibodies . this invention encompasses a method of generating high affinity monoclonal antibodies and their antigen binding fragments ( e . g ., fab ) for use in treating the medical problems associated with stimulant drug abuse . d - methamphetamine is the prototypic stimulant molecule because it has severe addiction liability and produces significant acute and chronic medical problems . anti - methamphetamine monoclonal antibody ( of any mammalian source ) may be used as a prototypic , long acting stimulant antagonist for treating addiction . in contrast , smaller molecular weight fragments ( like fab ) may be used as a prototypic shorter acting , less antigenic , more rapidly eliminated antagonist for treating drug overdose . since intact antibody and smaller fragments like fab are cleared by different organ systems , this approach will also provide a greater potential for altering and controlling the endogenous clearance and biological safety of these proteins . in addition to the obvious benefits of a new therapeutic approach , there would be other important contributions . in as much as the binding properties of receptors and antibodies are similar in many ways , the careful design of amphetamine - like haptens could lead to the selection of antibodies that mimic aspects of the endogenous binding sites of these drugs in the cns . molecular studies of these antibody binding sites ( through protein sequencing , structure - activity studies and molecular modeling ) could aid in the prediction of the characteristics necessary for drug - receptor interaction at sites of action including neuronal transporters , vesicular storage systems , and with monoamine oxidase . molecular studies of the sequence of the antibody binding site and the neuronal transporters may also yield important clues concerning the structural rules for molecular interactions of biologically active compounds . furthermore , the use of these antibody models for screening peptide and organic combinatorial libraries could lead to discovery of novel agonists or antagonists for these neuronal transporters . the present invention is directed to a monoclonal antibody that specifically recognizes a stimulant drug of abuse or a metabolite thereof . representative drugs of abuse or such metabolites include d - methamphetamine , d - amphetamine , 3 , 4 - methylenedioxymethamphetamine , and 3 , 4 - methylenedioxyamphetamine and or structural - related analogs of these compounds . in one form , the antibody is of murine origin . alternatively , the antibody is of human origin or contains portions of a human antibody . the present invention is also directed to an antigen binding fragment that specifically recognizes a stimulant drug of abuse or a metabolite thereof . representative drugs of abuse or metabolites are d - methamphetamine , d - amphetamine , 3 , 4 - methylenedioxymeth - amphetamine , and 3 , 4 - methylenedioxyamphetamine and or structural - related analogs of these compounds . in one form , the antibody is of murine origin . alternatively , the antibody is of human origin or contains portions of a human antibody . the present invention is also directed to a method of treating stimulant drug abuse , comprising the step of administering a pharmacological effective dose of the monoclonal antibody of the present invention to an individual in need of such treatment . representative stimulant drugs are described above . the present invention is also directed to a method of treating stimulant drug overdose , comprising the step of administering a pharmacological effective dose of the antigen binding fragment of the present invention to an individual in need of such treatment . the present invention is also directed to a compound with the structure of the present invention is also directed to a method of generating a class - specific monoclonal antibody that recognizes methamphetamine - like stimulants , comprising the step of : immunizing animals with the compound of the present invention ; generating antibody - secreting hybridomas from the spleen cells of said animals ; and screening the specificity of the antibodies , wherein antibody showing cross - reactivity to methamphetamine - like stimulants indicates the generation of methamphetamine - like stimulants - specific antibody . the present invention is also directed to a compound with the structure of wherein r is a hydrocarbon chain with a carboxylic acid terminus , and r is attached to the aromatic ring at position selected from the group consists of 2 , 3 , and 4 . this compound can possess ether ( s )— or ( r )- stereochemistry . in one embodiment , r is o ( ch 2 ) x cooh , and x is from 2 to 9 . in another embodiment , r is och 2 ch ═ ch ( ch2 ) x cooh , and x is from 1 to 6 . in another embodiment , r is och 2 c ═ c ( ch2 ) x cooh , and x is from 1 to 6 . in another embodiment , r is o ( ch 2 ) x o ( ch2 ) y cooh , and x is from 2 to 4 , y is from 1 to 5 . in another embodiment , r is o ( ch 2 ) x nr1 ( ch2 ) y cooh , x is from 2 to 3 , y is from 1 to 5 , and r1 is alkyl 1 - 5 carbon . in another embodiment , r is s ( ch 2 ) x cooh , and x is from 2 to 9 . in another embodiment , r is sch 2 ch ═ ch ( ch2 ) x cooh , and x is from 1 to 6 . in another embodiment , r is sch 2 c ═ c ( ch2 ) x cooh , and x is from 1 to 6 . in another embodiment , r is s ( ch 2 ) x o ( ch2 ) y cooh , and x is from 2 to 4 , y is from 1 to 5 . in another embodiment , r is s ( ch 2 ) x nr1 ( ch2 ) y cooh , x is from 2 to 3 , y is from 1 to 5 , and r1 is alkyl 1 - 5 carbon . in another embodiment , r is ( ch 2 ) x cooh , and x is from 3 to 8 . in another embodiment , r is ( ch2 ) x ch ═ chcooh , and x is from 2 to 7 . in another embodiment , r is ( ch2 ) x c ═ ccooh , and x is from 2 to 7 . in another embodiment , r is ch ═ ch ( ch2 ) x cooh , and x is from 1 to 6 . in another embodiment , r is c -≡ c ( ch2 ) x cooh , and x is from 1 to 6 . in another embodiment , the present invention further comprises of a hydrocarbon structure r1 attached to r , wherein r1 is selected from the group consisting of — ch 2 ch 2 cn , wherein said structure r1 couples said compound to a protein to form an immunogen for the generation of antibodies against methamphetamine - like stimulants . the following examples are given for the purpose of illustrating various embodiments of the invention and are not meant to limit the present invention in any fashion . generation of high affinity monoclonal antibodies and fab fragments that bind to d - methamphetamine and other stimulant drugs the haptens are coupled to a bovine serum albumin antigen by using a general synthesis procedure ( 6 ). this two - step , modified carbodiimide procedure permits a defined number of haptens to be covalently bound to the protein in a controlled molecular orientation . it also minimizes the cross linking of protein molecules , and the unwanted conjugation of the haptens through the free amino group on the d - methamphetamine haptens . a complimentary ovalbumin - d - methamphetamine hapten for use in screening hybridoma products in an enzyme - linked immunosorbent assay ( elisa ) and for use in testing for antibody production after active immunization of rats with a bsa - d - methamphetamine hapten was also generated . this general synthesis procedure has been used in the past to generate anti - drug antibodies ( 4 ) and anti - peptide antibodies ( 7 ). for the production of monoclonal antibodies , balb / c mice ( n = 6 - 10 per hapten ) are immunized with 100 μg of the bsa - d - methamphetamine , emulsified in an equal volume of an adjuvant ( e . g ., titer max , ribi , freund &# 39 ; s complete adjuvant ). one month later the animals were boosted with the same reagents and two weeks later the serum was tested for specific antibodies using the ovalbumin - d - methamphetamine conjugates in an elisa . the spleen from the animal with the highest titer of anti - d - methamphetamine antiserum was used for the first fusion . the other animals were boosted every three to four weeks to maintain titers of anti - d - methamphetamine in anticipation of future immunizations . after fusion of spleen cells from the mice with a myeloma cell line , hybridomas secreting anti - d - methamphetamine antibodies were identified using an elisa with the appropriate ovalbumin - d - methamphetamine conjugate as described ( 7 ). wells with a positive reaction to d - methamphetamine were subcloned to monoclonality . for specificity determinations , the antibodies were tested in an elisa format using a series of ligands . these ligands include ( but are not limited to ) d - and 1 - methamphetamine , d - and 1 - amphetamine , mdma , mda , ephedrine , pseudoephedrine , and other potentially cross reacting stimulant - like molecules and endogenous neurotransmitters . antibodies specific for the d - isomers and having a low kd value ( e . g ., & lt ; 1 - 30 nm ) were selected . although a range of antibody affinities has been studied ( as great as 250 nm ), the objective was to have affinity constants for methamphetamine in the range of 1 - 30 nm . once an anti - d - methamphetamine secreting hybridoma was chosen , large quantities of the antibody were produced in a hollow fiber bioreactor ( 3 ). a representative method for the monoclonal antibody purification process is as follows . after production , the monoclonal antibody - containing tissue culture media was combined and concentrated to one - tenth of the original volume using an amicon spiral cartridge concentration system . this technique takes approximately 10 minutes to concentrate 2 l down to 100 - 200 ml . the procedure recovers 95 % of the monoclonal antibody and removes & gt ; 95 % of the bovine albumin in the media . the concentrated monoclonal antibody was dialyzed against 50 mm mes buffer ( 2 -( n - morpholino )- ethanesulfonic acid ), ph 6 . 0 for further purification using a large , glass chromatography column packed with 1l of sp - sepharose big bead media ( pharmacia lkb biotechnology ). the sample was loaded on the column and washed with the mes buffer to remove non - specifically bound proteins . the monoclonal antibody was eluted in one step using 50 mm mes / 0 . 15 m nacl . this elution also serves to reconcentrate the monoclonal antibody . the purity and concentration of the purified anti - d - methamphetamine monoclonal antibody were determined by sds - page ( 5 ) and spectrophotometry respectively . the fab fragments of the monoclonal antibody were produced by the papain digestion method described by goding ( 8 ) using an mab : papain ratio of 500 : 1 ( w / w ). after digestion , the fab was purified using a hplc column containing pharmacia streamline deae sepharose anion exchange media . purity was checked by sds - page and the protein concentration measured with a coomassie protein assay or spectrophotometrically . for every 100 g of monoclonal antibody , one may expect to yield at least 55 - 68 g of fab fragments . for use in animals , the fab and monoclonal antibody were dialyzed against pbs , ph 7 . 4 and concentrated with an amicon ultrafiltration device to 50 - 100 mg / ml ( depending o n the needs of the in vivo testing procedure ). both fab and monoclonal antibody were stored at − 80 ° c . until needed . there was no decrease in binding activity or solubility after long - term storage of the monoclonal antibody or fab . one goal of the present invention was to generate a class - specific monoclonal antibody that could be used as a pharmacokinetic antagonist for treating the medical problems associated with methamphetamine - like stimulants . the methamphetamine - like stimulants that are most often abused are methamphetamine , amphetamine and mdma ( see fig3 ). based on review of the literature on anti - methamphetamine antibodies ( e . g ., faraj et al ., 1976 ; usagawa et al ., 1989 ; ward et al ., 1994 ) and analysis of the molecular features of the molecules shown in fig3 it is hypothesized that coupling of a spacer group ( with a carboxylic acid terminus ) at the para or meta position of the aromatic ring structure will offer the best chance for generating a class - specific antibody . the resulting antibodies are expected to react best with the parent compound , as opposed to metabolites , and would also be less likely to significantly cross react with natural neurotransmitters . if the protein was coupled to the amine groups at the other end of the molecule ( which would be more convenient ), this would not generate antibodies that would cross react with mdma . the haptens designed for generating antibodies specific for methamphetamine - like stimulants are illustrated in fig4 a - 4 c . a method of using activated ester to couple the hapten to a protein to make the antibody is shown in fig5 . similar chemistry would apply to all other structures shown in fig4 a - 4 c . the synthesis of one of the haptens ( hapten 1 in fig4 a with x = 5 and connected at the 3 - position ) is outlined in fig6 . the goal is to prepare the ( s )-(+)- isomer of 3 -( 5 ′- carboxy - pentyloxy ) methamphetamine ( 9 ). to establish the feasibility of the synthetic methods , the synthesis of ( r )-(−)- 9 is presented . those skilled in the art will know that ( s )-(+)- 9 can be prepared using exactly the same method starting with ( s )- α - methylbenzylamine . thus , to prepare ( r )- 9 , 3 - methoxyphenylacetone ( 1 ) was condensed with ( r )- α - methylbenzylamine to give 2 . raney nickel reduction of 2 followed by separation provided the pure ( r , r )- diastereoisomer 3 . the n - formyl - protected intermediate 4 was obtained by treating 3 with a formic acid - acetic anhydride mixture . o - demethylation of 4 using boron tribromide yielded the phenol 5 . alkylation of 5 with methyl 6 - bromohexanoate afforded 6 . reduction of 6 using diborane provided the n - ch 3 intermediate 7 , which yielded 8 on reduction using palladium on carbon catalyst in refluxing formic acid . the desired final optically pure hapten 9 as the hydrochloride salt was obtained by treating 8 with dilute hydrochloric acid . a solution of 3 - methoxyphenylacetone ( 10 g , 0 . 061 mol ) and ( r )- α - methylbenzylamine ( 7 . 38 g , 0 . 061 mol ) in 100 ml of dry toluene was heated to reflux in a flask fitted with a dean - stark condenser for 20 h . after cooling the reaction mixture , the solvent was removed , and the residue was dried under vacuum . the residual oil was dissolved in absolute etoh ( 60 ml ), and a slurry of etoh washed raney nickel was added . the resulting mixture was hydrogenated for 96 h at 40 psi hydrogen . the catalyst was removed by filtration over a celite bed , and the filtrate was treated with hcl gas . evaporation of the solvent gave a white solid which was triturated with hot acetone to provide the target compound 3 as a white solid . an analytical sample was prepared from an aliquot removed . the sample recrystallized from meoh / diethyl ether had mp 215 - 218 ° c . ; [ α ] 21 d ( 17 . 85 ° c . , c 1 . 95 , meoh ). 1 h nmr ( cd 3 od ) δ1 . 17 ( d , 3h ), 1 . 69 ( d , 3h ), 2 . 53 ( dd , 1h ), 3 . 17 ( m , 1h ), 3 . 31 ( m , 1h ), 3 . 74 ( s , 3h ), 4 . 63 ( q , 1h ), 6 . 59 ( s , 1h ), 6 . 62 ( d , 1h ), 6 . 82 ( d , 1h ), 7 . 21 ( t , 1h ), 7 . 54 ( m , 5h ). elemental analysis : calcd . for c 18 h 23 no . hcl : c , 70 . 69 ; h , 7 . 91 ; n , 4 . 58 ; cl , 11 . 59 . found : c , 70 . 51 ; h , 7 . 99 ; n , 4 . 53 ; cl , 11 . 65 . to a stirred solution of formic acid ( 7 . 5 ml , 0 . 2 mol ) a t 0 ° c . was added acetic anhydride ( 18 . 9 ml , 0 . 2 mol ) dropwise . after 30 min , the amine 3 ( 3 . 9 g , 13 . 7 mmol ) in a minimum volume of formic acid was added , and the mixture was stirred overnight . water was carefully added , and the mixture was neutralized with dilute nh 40 h . the mixture was extracted with ch 2 cl 2 , washed with saturated sodium chloride solution , and dried over naso 4 . the residue obtained after evaporation was purified on a silica gel column eluting with a solvent mixture of hexane / ch 2 cl 2 / ch 3 oh ( 5 : 14 : 1 ) to give 3 . 83 g ( 94 %) of 4 as a white solid . to a stirred solution of 4 ( 2 . 85 g , 10 mmol ) in ch 2 cl 2 ( 30 ml ) was added a solution of bbr 3 ( 4 . 84 g , 20 mmol ) in 50 ml of ch 2 cl 2 . after stirring overnight , the excess of bbr 3 was quenched by careful addition of water and the organic fraction separated . the aqueous layer was further extracted with ch 2 cl 2 , and the combined ch 2 cl 2 fraction was dried over na 2 so 4 . evaporation gave 2 . 01 g ( 74 %) of 4 as a white solid . further purification on a silica gel column eluting with hexane / ch 2 cl 2 / meoh ( 4 : 8 : 1 ) gave 1 . 65 g ( 61 %) pure product . the analytical sample was triturated with ether to give white crystals ; mp 174 - 177 ° c . elemental analysis : calcd . for c 18 h 21 no 2 . 1 . 25 h 2 o : c , 75 . 69 ; h , 7 . 50 ; n , 4 . 91 . found : c , 75 . 67 ; h , 7 . 46 ; n , 5 . 00 . to a suspension of hexane washed sodium hydride ( 21 6 mg , 4 . 32 mmol ) in 5 ml of dmf was added a solution of ( r , r )- 3 - hydroxyphenyl - 2 - propyl - n - formamido - n - α - methylbenzylamine ( 5 ) ( 1 . 22 g , 4 . 32 mmol ). after stirring for 30 min at room temperature , a solution of methyl 6 - bromohexanoate ( 1 . 36 g , 6 . 48 mmol ) in dmf ( 3 ml ) was added and stirred overnight at room temperature . the reaction mixture was diluted with h20 ( 50 ml ) and extracted with methylene chloride ( 3 × 10 ml ). the combined organic fraction was washed with saturated sodium chloride solution and dried over na 2 so 4 . after removal of the solvent , the residue was purified on a silica gel column . eluting with a solvent mixture ( ch 2 cl 2 : 5 hexane : meoh , 4 : 14 : 1 ) to give 1 . 68 g ( 95 %) of 6 . 1 h nmr (( cdcl 3 ) δ1 . 28 ( dd , 3h ), 1 . 53 ( m , 2h ), 1 . 58 ( dd , 3h ), 1 . 72 ( m , 4h ), 2 . 36 ( m , 2h ), 2 . 41 ( m , 1h ), 2 . 89 ( m , 1h ), 3 . 25 ( m , 1h ), 3 . 41 ( t , 2h ), 3 . 68 ( s , 3h ), 3 . 82 ( q , 2h ), 4 . 58 , 6 . 07 ( 2 q , 1h ), 6 . 17 , 6 . 67 ( 2 s , 1h ), 6 . 57 , 6 . 40 ( 2d , 1h ), 6 . 67 ( dd , 1h ), 7 . 05 ( dd , 1h ), 7 . 36 ( m , 5h ), 8 . 41 , and 8 . 48 ( two s , 1h ). the sample was used in the next step without further characterization . a solution of the above formamide ( 1 . 63 g ) was treated with bh 3 . thf ( 10 ml ) and stirred for 30 min when the excess of bh3 was decomposed with meoh followed by dilute hcl . the reaction mixture was basified with dilute nh40h and extracted with methylene chloride ( 3 × 25 ml ). the organic fraction was dried over na 2 so 4 and evaporated to dryness . the oily material was dissolved in meoh ( 25 ml ), and pd / c ( 250 mg ) was added . the mixture was heated to reflux with formic acid ( 3 ml in three portions ) for an hour . the filtrate , obtained after removal of the catalyst , was evaporated and the resulting residue purified on a silica gel column . elution with 10 % meoh in methylene chloride gave 0 . 84 g ( 70 % overall in two steps ) of a clear oil . 1 h nmr (( cdcl 3 ) 1 . 06 ( d , 3h ), 1 . 50 ( m , 2h ), 1 . 71 ( m , 2h ), 1 . 80 ( m , 2h ), 2 . 33 ( t , 2h ), 2 . 41 ( s , 3h ), 3 . 67 ( s , 3h ), 3 . 95 ( t , 2h ), 6 . 75 ( m , 3h ), 7 . 19 ( m , 1h ). the sample was converted to hcl salt ; mp 53 - 57 ° c . elemental analysis : calcd . for c 17 h 27 no 3 . hcl . 0 . 75 h 2 o : c , 59 . 50 ; h , 8 . 50 ; n , 4 . 10 . found : c , 59 . 65 ; h , 8 . 45 ; n , 4 . 21 . a solution 8 ( 400 mg , 1 . 15 mmol ) in dilute hydrochloric acid ( 6n , 5 ml ) was heated to reflux for 4 h . the reaction was evaporated to dryness , and the residue was crystallized from meoh / ether to give 215 mg ( 59 %) of an off - white crystalline material : mp 73 - 77 ° c . 1 h nmr ( cd 3 od ) 1 . 25 ( d , 3h ), 1 . 34 ( m , 2h ), 1 . 40 ( m , 2h ), 1 . 67 ( m , 2h ), 2 . 65 ( t , 2h ), 2 . 72 ( s , 3h ), 4 . 22 ( m , 2h ), 6 . 73 ( m , 3 ), 7 . 13 ( s , 1h ). elemental analysis : calcd . for c 16 h 25 no 3 . hcl . 0 . 25 h 2 o : c , 59 . 99 ; h , 8 . 34 ; n , 4 . 37 ; cl , 11 . 07 . found : c , 60 . 09 ; h , 8 . 33 ; n , 4 . 37 ; cl , 11 . 13 . effect of hapten design on antibody specificity for d - amphetamine like drugs in these experiments , rabbit antiserum was generated against two unique d - methamphetamine like haptens . each hapten included the basic chemical structure of d - methamphetamine , along with a new chemical linker group attached at the para ( para - o , 6 hapten ) or meta ( meta - o , 6 hapten ) positions of the aromatic ring structure . the distal end of this linker group had a carboxy terminus for use in forming a peptide bond with protein antigens . after synthesis of a hapten - bovine serum albumin conjugate , this antigen was used for immunizing two rabbits . the first immunization for each rabbit was with 200 μg of either para - o , 6 antigen or meta - o , 6 antigen in freund &# 39 ; s complete adjuvant . the first booster immunization was with 100 μg of antigen in freund &# 39 ; s incomplete adjuvant . seven to ten days later each animal was bled and the serum was collected for testing . after titering each antiserum for selection of a n appropriate serum dilution for radioimmunoassay , the relative cross - reactivity of each antiserum was determined . in this assay , a constant dilution of antiserum and a constant amount of [ 3 h ]- methamphetamine was added to each test tube . next , increasing amounts of either d - amphetamine or d - methamphetamine were added to separate tubes . after an overnight incubation at 4 - 8 ° c ., the antibody bound [ 3 h ]- methamphetamine was separated from the free [ 3 h ]- methamphetamine using a goat anti - rabbit second antibody . the antibody precipitate in each tube was then transferred to a scintillation vial and the amount of radioactivity in each tube was determined by liquid scintillation spectrometry . for each of the test drugs ( either d - amphetamine or d - methamphetamine ), the ed 50 value for inhibition of [ 3 h ]- methamphetamine binding to each antiserum was determined using a sigmoidal ( logistic ) fit to the percentage of [ 3 h ]- methamphetamine binding versus log ligand dose . results from these studies show that the antiserum generated from the para - o , 6 hapten ( right two dose - response curves , fig7 ) is significantly more specific for d - methamphetamine ( ed 50 = 427 nm ) than it is for d - amphetamine ( ed 50 = 5157 nm ). indeed the relative cross reactivity for d - amphetamine is only 8 . 3 % ( 427 nm / 5157 nm × 100 %) of the value for d - methamphetamine . thus , while this hapten might be useful in developing a highly specific assay for detection of d - methamphetamine , it would not be useful in generating a monoclonal antibody - based medication with high affinity and broad recognition for d - amphetamine like drugs . in contrast , results from the radioimmunoassay analysis of the meta - o , 6 antiserum ( left two dose - response curves , fig7 ) showed d - amphetamine ( ed 50 = 47 nm ) cross - reactivity is 59 . 6 % ( 28 nm / 47 nm × 100 %) of the value for d - methamphetamine ( ed 50 = 28 nm ). in these studies the meta - o , 6 hapten also generated higher affinity antiserum than the para - o , 6 hapten , as determined from the significantly lower ed 50 values for both d - amphetamine and d - methamphetamine . as an object of this invention is to generate a widely cross - reacting antiserum for d - amphetamine - like drugs , these data show the importance and uniqueness of the hapten design . comparison of active and passive immunization as treatments for d - methamphetamine addiction a series of male sprague - dawley rats were immunized with a d - methamphetamine - like hapten until high titers were achieved , or treated with anti - d - methamphetamine mab . the rats were then repeatedly challenged with i . v . d - methamphetamine over several weeks . the ability of the antibodies to antagonize drug effects over an extended time period was assessed using d - methamphetamine dose - response curves with dosing schedules that are designed to simulate repeated binge use of the drug , and behavioral measurements of response . the rats for all of these studies were purchased with indwelling jugular venous catheters for i . v . administration of d - methamphetamine and anti - d - methamphetamine mab . for active immunization , one group of rats ( n = 6 for all groups ) was immunized over a six week period prior to the start of the studies . an example immunization plan was 100 μg of the bsa - d - methamphetamine , emulsified in an equal volume of titer - max as the adjuvant , followed at weeks 3 and 6 by a booster immunization . ten days after the last boost , the anti - d - methamphetamine serum titers are checked in an elisa . if the titers are elevated , behavioral testing begins on day 10 - 14 after the last boost . for passive immunization , another group of rats was treated with 400 mg dose of monoclonal antibody the day before the start of the study . this dose of anti - d - methamphetamine monoclonal antibody ( 400 mg ) should have the capacity to bind up to 2 . 1 mg / kg of d - methamphetamine on day 1 of the behavioral experiments , and up to 0 . 52 mg / kg of d - methamphetamine on day 16 ( our final day of testing , see below ). a 2 . 1 mg / kg dose of d - methamphetamine in the rat would be about equivalent to a 150 mg binge use of d - methamphetamine in an average size human ( i . e ., about 150 lbs ). the calculation of the d - methamphetamine ( m . w . 149 g / mol ) mol - eq dose of igg assumes a 350 g rat , two igg binding sites , a mass of 150 , 000 kda , an in vivo first - order monoexponential loss of the igg , and an igg t 1 / 2 of 8 . 1 days ( 9 ). the effectiveness of each therapy was measured by accessing the cumulative behavioral effects after administration of a range of d - methamphetamine doses over a 3 hr time period . this d - methamphetamine dosing strategy was used to simulate binge drug use , and an addict &# 39 ; s attempt to surmount the blocking effects of the antagonist by the self - administration of progressively higher doses . the i . v . doses of 0 . 1 , 0 . 3 and 1 . 0 mg / kg are administered at 0 , 1 . 5 hrs and 3 . 0 hrs , respectively . this simulated binge dosing was repeated every 4 days ( day 1 , 4 , 8 , 12 and 16 ) for up to 16 days . the ethovision system , which has video tracking and digitized motion analysis , was used for continuous behavioral monitoring . d - methamphetamine - induced locomotor activity , e . g ., distance traveled , percentage of the time spent moving , and animal rearing , were measured over a 6 hr period . from each day of behavioral experiments , the time to maximum effects after each dose of d - methamphetamine , the maximum effect , the area under the behavioral effect curve from the time of dosing to the end of each type of behavioral effect , and the duration of effects were calculated . the end of each behavioral effect was based on a statistical analysis of the average baseline response prior to drug administration . for instance , the point at which the animals &# 39 ; response has returned to 1 + s . d . of the mean pre - drug response for two consecutive 2 min intervals . the data were analyzed by a two - way ( dose of d - methamphetamine and time ) repeated measures anova , followed by a student - newman - keuls post hoc test . the results were considered significant at p & lt ; 0 . 05 . effect of anti - d - methamphetamine mab on pharmacokinetics and behavior after stimulant - induced toxicity in rats the ability of immunotherapy to reverse toxicity resulting from high doses of d - methamphetamine was examined as follows . for the pharmacokinetic studies , antibody - induced changes in d - methamphetamine disposition , protein binding , and the tissue distribution of d - methamphetamine in rats are examined . for behavioral studies , changes in d - methamphetamine - induced behavioral effects , the time needed for the reversal of effects , and pharmacokinetic and pharmacodynamic relationships are examined . to characterize the plasma concentration - time profiles of d - methamphetamine , anti - d - methamphetamine monoclonal antibody and anti - d - methamphetamine fab following i . v . administration , male sprague - dawley rats ( n = 4 per group ) purchased with indwelling jugular venous and femoral arterial catheters are placed in a metabolic cage and injected with either d - methamphetamine ( 0 . 5 mg / kg of d - methamphetamine along with a tracer dose of [ 3 h ] d - methamphetamine ) or the appropriate antibody ( 100 mg of monoclonal antibody or 100 mg of fab ). the dose is administered as a 15 sec bolus dose via the jugular catheter . aliquots of arterial blood are removed from the arterial catheter . the rats are kept in a metabolic cage for collection of urine , with free access to food and water . for each molecule ( d - methamphetamine , mab , fab ), the values for the volume of distribution at steady - state , systemic clearance , renal clearance , terminal elimination half - life , and the fraction of the drug appearing in the urine were calculated by using winnonlin ( pharsight corporation , mountain view , calif .). the equations for these calculations can be found in the text by gibaldi and perrier ( 10 ). the effect of the anti - d - methamphetamine fab on the tissue distribution of d - methamphetamine was determined in the following representative method of analysis . rats were injected with d - methamphetamine ( 0 . 5 mg / kg along with a tracer dose of [ 3 h ] d - methamphetamine ) as a 15 sec i . v . bolus via their jugular catheter . at 30 min after d - methamphetamine administration , fab - treated animals ( n = 3 per time point × 10 tissue collection time points from 45 min to 24 hrs ) received an i . v . injection of monoclonal anti - d - methamphetamine fab in 1 ml of phosphate - buffered saline ( ph 7 . 4 ). the dose of anti - d - methamphetamine fab administered to each animal was approximately mol - eq in binding sites to the amount of d - methamphetamine remaining in the rat at 30 min ( or about 80 % of the i . v . d - methamphetamine dose ). at 30 , 45 , 60 , 90 120 , 210 , 300 min and 8 , 18 and 24 hrs after drug administration , the animals were anesthetized with diethyl ether ( in a laboratory hood for safety ) and blood was collected from the posterior vena cava . blood , brain , liver , heart , lung , right kidney , and right testis were harvested as quickly as possible in this order . the tissues were rinsed with water , weighed , and quick frozen in liquid nitrogen . blood samples were allowed to clot and then centrifuged for plasma collection . plasma and organ samples were stored at − 80 ° c . until extracted and analyzed for d - methamphetamine using a hplc method similar to that published by burchfield et al . ( 11 ). briefly , plasma samples were alkalinized with sodium carbonate and extracted with hexane . after mixing and centrifugation , the hexane phase were acidified with 0 . 1n hcl , mixed , and centrifuged . the hcl phase was injected into the hplc column . the mobile phase consists of 1 % phosphoric acid , 4 mmol / l dodecyl sodium sulfate with 20 % acetonitrile at 2 ml / min , using a reverse phase column . tissue samples were weighed and homogenized with hcl and the propylamphetamine internal standard . this homogenate mixture was processed exactly as the plasma samples for d - methamphetamine determination . for determining the ability of antibodies to reverse acute toxicity , dose of d - methamphetamine that produces significant toxic effects , but not a life threatening dose , was administrated . the dose was selected based on d - methamphetamine dose - behavioral response studies conducted in the laboratory . in the treatment experiments , the anti - d - methamphetamine fab was injected at least 30 min after the d - methamphetamine when effects are maximal . the doses of anti - d - methamphetamine fab were administered in equimolar amounts to the amount of methamphetamine remaining in the animal at 30 minutes . for control treatments , the animals were administered saline or an anti - phencyclidine ( anti - pcp ) monoclonal antibody ( of the same isotype ). this anti - pcp monoclonal antibody provides a negative antibody control since this antibody does not cross - react with d - amphetamine - like drugs . the animals are allowed to recover for at least 3 days between treatments ( saline , anti - pcp monoclonal antibody , anti - meth fab in a repeated - measures , mixed - sequence design ). the success of the therapy is determined by statistically significant changes in behavioral measures . the behavioral data from total movement , distance traveled , rearing and the duration of each behavioral effect are normalized to a percentage of the maximal response of the drug for each animal without antibody treatment . use of monoclonal antibodies to treat a methamphetamine - induced drug overdose in male rats ( a preclinical model of human drug overdose ) the hapten used for the production of the monoclonal antibodies was similar in design to the para - 4 hapten described in example 3 . this hapten design is known to generate highly selective antibodies for d - methamphetamine , which do not have significant cross - reactivity with d - amphetamine . thus , in this rat model of human overdose the antibody will bind to d - methamphetamine , but it is not expected to completely reduce meth - induced toxicity since pharmacokinetic studies of intravenous d - methamphetamine in the rat show there is significant amount of the psychoactive d - amphetamine metabolite in the brain . nevertheless , these studies provide the proof of concept that monoclonal anti - methamphetamine monoclonal antibody fragments can produce beneficial therapeutic effects resulting for a d - methamphetamine overdose . monoclonal antibodies were produced against a methamphetamine - like hapten with a four - member spacer group attached at the para position of the aromatic ring structure of methamphetamine ( hapten 11 in fig4 c with x = 3 and connected at the 4 position ). the hapten was covalently bound to bovine serum albumin , through a covalent peptide bond at the end of the four - carbon spacer group away from its attachment to the aromatic ring structure of methamphetamine . the anti - methamphetamine monoclonal antibodies were produced from cell line 6h8 in a cell - pharm system hollow bioreactor ( unisyn technologies , inc ., hopkinton , mass . ), as described elsewhere ( valentine et al ., 1996 ). monoclonal igg from the bioreactor product was purified using a two - step procedure . cell culture media was diluted ( 1 : 5 ) with deionized water and the ph adjusted to 6 . 0 with hcl . this solution was passed through a cation exchange sp sepharose big beads ( pharmacia biotech ) chromatography column . the column was rinsed with buffer ( mes buffer 50 mm ph 6 . 0 ). when the absorbance returned to baseline igg was eluted using buffer ( mes 50 mm ph 6 . 0 containing 150 mm nacl ). the fab fragments were prepared from the purified monoclonal igg by the method described by mcclurkan et al . ( 1993 ) for the purification of anti - pcp fab fragments . purified anti - methamphetamine fab fragments were then concentrated and the buffer changed to sodium phosphate 15 mm ph 7 . 2 containing 150 mm of nacl , using a high pressure concentrator system ( amicon , beverly , mass .). the final concentration of fab was between 40 and 50 mg / ml . the quality and purity of product were checked using sds - page , immunoelectrophoresis , isoelectric focusing and by running it through a molecular size column . according to sds - page and molecular weight sizing column , the anti - methamphetamine fab preparation was at least 95 % pure . the monoclonal anti - pcp fab , which was used as a control antibody , was prepared in the same manner . adult male sprague - dawley rats ( 300 g ) were purchased from hilltop laboratories ( scottsdale , pa . ), with a cannula implanted in the right jugular vein . these cannulae were used for all injection of saline , drug and treatments ( saline , anti - pcp fab and anti - meth fab ). prior to the beginning of the experiments , rats were allowed to habituate to the behavioral testing environment ( an 1 . 5 × 3 ft open top polypropylene chamber containing gray non - reflective gravel ). behavioral analysis was conducted by the methods of hardin et al . ( 1998 ). this method allowed the accurate quantitation and comparison of the distance traveled and the number of rearing events during the entire testing period . these behavioral measurements were used as sensitive indicators because of the potent effect that d - methamphetamine has on rodent spontaneous locomotor activity . all dosing for behavioral measurements was conducted in a repeated - measures , mixed - sequences protocol . rats were placed in the chambers 60 minutes before the administration of any saline , drug or treatments . saline or d - methamphetamine was administered at time 0 for all groups , as a no effect control ( saline ) or to produce drug effects ( d - methamphetamine ). saline or anti - methamphetamine fab or anti - pcp fab ( in a 3 ml final volume ) was administered at time 30 minutes , to determine the effects of no treatment ( saline ) or a control monoclonal antibody ( a monoclonal anti - pcp fab or a control monoclonal antibody that does not bind methamphetamine ) or the test treatment ( monoclonal anti - methamphetamine fab from hybridoma cell line 6h8 ). each rat received four different treatments . the treatments were : saline followed by saline ( for determination of baseline activity ), methamphetamine followed by saline ( for determination of baseline methamphetamine - induced effects ), methamphetamine followed by anti - pcp fab ( for determination of the baseline effect of a matched antibody control that does not bind to methamphetamine ), and methamphetamine followed by anti - methamphetamine fab ( to determine if the methamphetamine - specific therapy has any effects on the methamphetamine - induced overdose ). the dose of fab ( either anti - pcp or anti - methamphetamine fab ) was calculated to have sufficient capacity to neutralize the body burden of methamphetamine at the time of administration ( i . e ., 30 min after the methamphetamine administration ). the amount administered was a mole - equivalent dose of fab to the methamphetamine in the rat at 30 min after the intravenous injection of methamphetamine . these calculations were based on the methamphetamine pharmacokinetic parameters determined by reverie et al ., ( 1999 ). results from the administration of saline or methamphetamine without treatments were computer analyzed by summing the rat activity during 2 - min measurement intervals from the time of injection of saline or methamphetamine ( at time 0 ) until the end of the experiment . results for each rat were normalized against the their baseline methamphetamine activity , resulting from the 1 mg / kg dose of methamphetamine ( i . e ., this treatment was considered 100 % activity ). results from experiments testing the effects of treatments ( e . g ., anti - methamphetamine fab ) were determined from the duration of action of the drug using a statistical approach . the mean + 1 sd of the baseline activity ( after saline injection , followed by a saline treatment at 30 minutes ) was calculated from 36 minutes until the end of the experiment . for each experiment , meth effects were considered over when two consecutive 2 - min testing intervals were equal to or below the mean + 1 sd of the baseline rat activity . this analysis was conducted for both the measurements of distance traveled and the number of rearing events . all values are expressed as mean ± sd . statistical comparisons of behavior experiments were determined using a one - way repeated - measure anova . when the f value was significant ( p & lt ; 0 . 05 ), a post - hoc pairwise multiple comparison was conducted using a student - newman - keuls test . the level of significance was set at p & lt ; 0 . 05 . based on the distance traveled parameter , the duration of action of methamphetamine - induced effects following a 1 mg / kg iv dose was about two hours ( 116 ± 17 min ). after treatment with anti - pcp fab the duration of activity was 111 ± 10 min . after treatment with anti - methamphetamine fab the duration of activity was 75 ± 22 min . both the distance traveled ( fig8 a ) and the number of rearing events ( fig8 b ) were significantly different from the behaviors produced by saline followed by methamphetamine administration ( p & lt ; 0 . 05 ). the anti - pcp fab treatment produced some mild reductions in methamphetamine - induced locomotor activity , which were similar to the mild reductions in behavior we have found in other experiments in which polyclonal non - specific antibody is used to treat pcp - induced locomotor activity . as a percentage of the control saline treatment , the monoclonal anti - methamphetamine fab produced a 55 % decrease in the distance traveled ( see fig8 a ). the number of rearing events ( see fig8 b ) and the time spent moving ( results not shown ) were also decreased by 55 % and 60 %, respectively . since the monoclonal antibody used for these studies did not significantly bind to d - amphetamine ( a psychoactive metabolite present at very high levels in the rat , but at significantly lower levels in the human ) and it was a low affinity antibody ( about 250 nm ), the therapeutic potential for antibody based medications for overdose are quite significant . this is especially important since no therapies currently exist . with the use of improved hapten design ( see example 2 ) and production of antibodies with significantly lower kd values ( e . g ., & lt ; 30 nm ), this invention should provide a significant breakthrough in treatment of overdose due to d - amphetamine - like drugs . this is supported by experiments using a monoclonal antibody 6h4 that has a kd of 11 nm , which is approximately 25 x lower kd value than the 250 kd monoclonal antibody used in the previous studies . this new antibody is highly specific for (+) meth and (+) mdma , with little to no cross reactivity with (+) amp or (+) mda , or the minus isomers of these chemicals . the following experimental data show the feasibility of using this or other monoclonal antibodies in two different preclinical scenarios : drug overdose and the use of pretreatment with monoclonal antibody therapy to block the pharmacological effects of methamphetamine abuse . use of an 11 nm kd anti -(+) meth monoclonal tgg antibody to reverse drug overdose rats ( n = 6 / group ) were administered i . v . (+) methamphetamine ( 1 . 0 mg / kg ) 3 days apart on two occasions to stabilize locomotor responses and to minimize sensitization . then 1 . 0 mg / kg of (+) methamphetamine was administered i . v ., and 30 min later ( when effects were maximal ) a dose of 367 mg / kg of anti - methamphetamine monoclonal antibody was administered . this dose was equimolar ( in binding sites ) to the rat body burden of (+) methamphetamine . as shown in fig9 a , the anti -(+) methamphetamine monoclonal antibody significantly ( p & lt ; 0 . 05 ) reduced (+) methamphetamine induced effects by 72 % for distance traveled ( left ) and by 76 % for rearing events ( right ). the monoclonal antibody significantly shortened the duration of action of (+) methamphetamine from 112 to 32 min . saline control treatments , conducted before and after the experimental protocol showed that baseline activity was stable over an extended period . pretreatment with an 11 nm kd anti -(+) methamphetame monoclonal igg antibody to reduce the effects of (+) methamphetamine in an rat model of drug abuse rats ( n = 7 / group ) were administered a dose of 502 mg / kg of anti - methamphetamine monoclonal antibody on day 1 . the following day they were administered i . v . (+) methamphetamine ( 1 . 0 mg / kg ) 3 days apart on two occasions to stabilize locomotor responses and to minimize sensitization . then 1 . 0 mg / kg of (+) methamphetamine was administered i . v . this dose was equimolar ( in binding sites ) to a 1 mg / kg dose of (+) methamphetamine . as shown in fig9 b , the anti -(+) methamphetamine monoclonal antibody significantly ( p & lt ; 0 . 05 ) reduced (+) methamphetamine induced effects by 42 % for distance traveled ( left ) and by 51 % for rearing events ( right ). the monoclonal antibody significantly shortened the duration of action of (+) methamphetamine from about 160 to 80 min . saline control treatments conducted before and after the experimental protocol showed that baseline activity was stable over an extended period . impact of anti - d - methamphetamine therapy on drug self - administration and drug discrimination as a measure of treating long - term addiction drug self - administration is generally considered to be a measure of the reinforcing properties of a drug and is widely used to measure the addiction liability of different drugs . before self - administration of methamphetamine by a rat can be used as a model of the pharmacotherapeutic effects of anti - methamphetamine igg , it is necessary to develop a suitable methamphetamine self - administration model . therefore , four rats with external carotid catheters were trained to respond on a lever for food . once conditioned for this response , food was discontinued and each response on a lever in the cage produces an injection of 0 . 06 mg / kg d - methamphetamine . after several sessions under this schedule , the reinforcement schedule was changed to fixed - ratio 3 , such that 3 responses are required to produce each injection of d - methamphetamine . the d - methamphetamine was available for two hours each day , after which the rat is returned to the home cage until the next session . sessions were conducted 7 days a week . after responding for d - methamphetamine is stable , the pharmacotherapeutic effects of anti - methamphetamine igg were tested . conditioned rats were administered an anti - methamphetamine igg and the next day the rat was given the opportunity to respond for d - methamphetamine injections . a significant increase in the number of responses during a session indicates that the antibody was blocking only some of the reinforcing properties of the d - methamphetamine , and the animal was surmounting the protective effects of the antibody . a significant decrease in the number of responses during a session indicates that the antibody is blocking the all or most of the reinforcing properties of the d - methamphetamine in the drug discrimination procedure , animals were trained to recognize the presence or absence of a training drug by differential reinforcement of responses in the presence or absence of the drug . animals were trained to respond on one lever to obtain food if drug has been administered and on another lever if the drug vehicle has been administered . the only cue that the animal has as to which responses will be reinforced each day is the interceptive stimuli produced by the drug . once the discrimination is established , other doses of the training drug or doses of other drugs are administered to determine if they produce interceptive stimuli that can substitute for those of the training drug . to study the effectiveness of immunotherapy for d - methamphetamine abuse , pigeons were trained to discriminate among pentobarbital , morphine , d - amphetamine and saline using a 4 - key discrimination procedure where responding on the correct key was reinforced with food delivery under a fixed - ratio schedule . d - methamphetamine generalizes completely to the training drug d - amphetamine in these sessions . to determine if the d - methamphetamine discriminative stimulus could be blocked with the anti - methamphetamine antibody , pigeons were administered the antibody intravenously approximately 14 hours before determination of a cumulative methamphetamine dose - response curve . the hapten used for the production of the monoclonal antibodies was similar in design to the para - 4 hapten described in example 6 . this hapten design is known to generate highly selective antibodies for d - methamphetamine , which do not have significant cross - reactivity with d - amphetamine . thus , in this pigeon model of drug discrimination the antibody will bind to d - methamphetamine , but it is not expected to blunt or block effects due to other drugs including d - amphetamine , pentobarbital and morphine ( the drug discrimination test compounds ) metabolite in the brain . nevertheless , these studies provide the proof of concept that monoclonal anti - methamphetamine monoclonal antibody igg can produce beneficial , long lasting and selective therapeutic effects for d - methamphetamine . inability to correctly identify the drug and a subsequent shifting of the methamphetamine dose - response curve in the presence of antibody indicates blockage of the drug discriminative stimulus . as shown in fig1 , the anti - methamphetamine igg produced a significant shift in the d - methamphetamine dose response curve for at least 22 days . since this antibody did not have significant cross reactivity with d - amphetamine , pentobarbital or morphine , it offered no protection against the effects of these drugs . thus , these studies provide proof of the potential for long lasting and selective effects in humans . effect of antibody - based therapy on d - metbampbetamine toxicity in large animal model a battery of pharmacokinetics studies and behavioral tests are used to determine whether anti - d - methamphetamine fab can reverse acute behavioral toxicity due to d - methamphetamine in large animals like large dogs ( or primates ). these data will help to determine the ability of anti - d - methamphetamine fab to redistribute d - methamphetamine in a large animal model and help to scale - up the therapy to humans . d - methamphetamine is administered to male dogs ( or primates ; n = 6 per group , 3 males and 3 females ) at 0 . 3 mg / kg or higher depending on results of preliminary d - methamphetamine dose - response studies . if needed for quantitation ( see example 5 ), a tracer dose of [ 3 h ]- d - methamphetamine will also be administered . after the drug is fully distributed ( e . g ., 30 - 45 min ), anti - d - methamphetamine fab is administered at a 1 . 0 mol - eq dose to the amount of d - methamphetamine remaining in the dog ( or primate ) at 30 min . the exact timing and dosing depend on the outcome of the rat studies and the preliminary pharmacokinetic studies in dogs or primates . plasma and urine d - methamphetamine pharmacokinetics are determined in each dog or primate as described above . the analytical methods for d - methamphetamine and anti - d - methamphetamine fab are the same as those described in example 5 . the same dogs ( or primates ) are used for the pharmacokinetic and behavioral studies for continuity . however , the success of the experiments is not dependent on using the same dog ( or primate ) for all experiments ( n = 6 ). for the behavioral experiments , d - methamphetamine are administered to dogs ( or primates ) at 0 . 3 mg / kg ( or higher ) followed 30 - 45 min later by a 0 . 1 , 0 . 3 , or 1 . 0 mol - eq dose of anti - d - methamphetamine fab . the experiments are done in a pre - determined repeated - measures , mixed - sequence design . the same measures of behavior ( and the ethovision system ) as described above are used for the studies of d - methamphetamine acute toxicity . 3 . valentine and owens , j . pharmacol . exp . ther . 278 : 717 - 724 ( 1996 ). 4 . owens et al ., j . pharmacol . exp . ther . 246 : 472 - 478 ( 1988 ). 5 . mcclurkan et al ., j . pharmacol . exp . ther . 266 : 1439 - 1445 ( 1993 ). 7 . laurenzana et al ., drug metab . dispos . 23 : 271 - 278 ( 1995 ). 8 . goding , monoclonal antibodies : principles and practice . pp . 118 - 122 , academic press , new york ( 1983 ). any patents or publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains . these patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically incorporated by reference . one skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned , as well as those inherent therein . the present examples along with the methods , procedures , treatments , molecules , and specific compounds described herein are presently representative of preferred embodiments , are exemplary , and are not intended as limitations on the scope of the invention . changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention as defined by the scope of the claims .
the invention includes synthetic immunochemical haptens for the generation of antibodies , the antibodies , and the medical treatment applications for using the antibodies . the antibodies are designed to recognize the common molecular features of d - methamphetamine - like abused stimulants , and will have insignificant cross - reactivity with endogenous substrates or over - the - counter medications . these monoclonal antibodies and their antigen binding fragments are useful in treatment plans for recovering addicts , in emergency room settings for rapidly reversing a drug overdose , in protection of fetuses or fetus from drug - abusing pregnant mothers or in a psychiatric setting to reduce the exacerbation of psychotic disorders caused by stimulant drugs .