“ vial ” means a small glass container sealed with the most suitable stopper and seal , other suitable primary containers may be used , for instance , but not limited to , pre - filled syringes . vial also means a sealed container of medication that is used one time only , and includes breakable and non - breakable glass vials , breakable plastic vials , miniature screw - top jars , and any other type of container of a size capable of holding only one unit dose of palonosetron ( typically about 5 mls .). throughout this specification the word “ comprise ,” or variations such as “ comprises ” or “ comprising ,” will be understood to imply the inclusion of a stated element , integer or step , or group of elements , integers or steps , but not the exclusion of any other element , integer or step , or group of elements , integers or steps “ palonosetron ” means ( 3as )- 2 , 3 , 3a , 4 , 5 , 6 - hexahydro - 2 -[( s )- 1 - azabicyclo [ 2 . 2 . 2 ] oct - 3 - yl ] 2 , 3 , 3a , 4 , 5 , 6 - hexahydro - 1 - oxo - 1hbenz [ de ] isoquinoline , and is preferably present as the monohydrochloride . palonosetron monohydrochloride can be represented by the following chemical structure : concentrations — when concentrations of palonosetron are given herein , the concentration is measured in terms of the weight of the free base . concentrations of all other ingredients are given based on the weight of ingredient added to the solution . “ pharmaceutically acceptable ” means that which is useful in preparing a pharmaceutical composition that is generally safe , non - toxic and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary use as well as human pharmaceutical use . “ pharmaceutically acceptable salts ” means salts which are pharmaceutically acceptable , as defined above , and which possess the desired pharmacological activity . such salts include acid addition salts formed with inorganic acids such as hydrochloric acid , hydrobromic acid , sulfuric acid , nitric acid , phosphoric acid , and the like ; or with organic acids such as acetic acid , propionic acid , hexanoic acid , heptanoic acid , cyclopentanepropionic acid , glycolic acid , pyruvic acid , lactic acid , malonic acid , succinic acid , malic acid , maleic acid , fumaric acid , tartaric acid , citric acid , benzoic acid , o -( 4 - hydroxybenzoyl ) benzoic acid , cinnamic acid , mandelic acid , methanesulfonic acid , ethanesulfonic acid , 1 , 2 ,- ethanedisulfonic acid , 2 - hydroxyethanesulfonic acid , benzenesulfonic acid p - chlorobenzenesulfonic acid , 2 - naphthalenesulfonic acid , p - toluenesulfonic acid , camphorsulfonic acid , 4 - methylbicyclo [ 2 . 2 . 2 ] oct - 2 - ene - 1 - carboxylic acid , glucoheptonic acid , 4 , 4 ′- methylenebis ( 3 - hydroxy - 2 - ene - 1 - carboxylic acid ), 3 - phenylpropionic acid , trimethylacetic acid , tertiary butylacetic acid , lauryl sulfuric acid , gluconic acid , glutamic acid , hydroxynaphthoic acid , salicylic acid , stearic acid , muconic acid , and the like . in addition , pharmaceutically acceptable salts may be formed when an acidic proton present is capable of reacting with inorganic or organic bases . acceptable inorganic bases include sodium hydroxide , sodium carbonate , potassium hydroxide , aluminum hydroxide and calcium hydroxide . acceptable organic bases include ethanolamine , diethanolamine , triethanolamine , tromethamine , n - methylglucamine and the like . the fact that palonosetron can be formulated in some instances at concentrations of only about 1 / 10 th the amount of other previously known compounds for treating emesis , surprisingly allows the use of concentrations of palonosetron far below those that would ordinarily be expected . thus , in one embodiment the invention provides a pharmaceutically stable solution for preventing or reducing emesis comprising a ) from about 0 . 01 mg / ml to about 5 mg / ml palonosetron or a pharmaceutically acceptable salt thereof ; and b ) a pharmaceutically acceptable carrier . similarly , in another embodiment the invention provides a method of formulating a pharmaceutically stable solution of palonosetron comprising admixing from about 0 . 01 mg / ml to about 5 mg / ml palonosetron or a pharmaceutically acceptable salt thereof ; with a pharmaceutically acceptable carrier . in alternative embodiments , the formulation includes palonosetron or a pharmaceutically acceptable salt thereof in a concentration from about 0 . 02 mg / ml to about 1 . 0 mg / ml , from about 0 . 03 mg / ml to about 0 . 2 mg / ml , and most optimally about 0 . 05 mg / ml . a particular advantage associated with the lower dosages of intravenous palonosetron is the ability to administer the drug in a single intravenous bolus over a short , discrete time period . this time period generally extends from about 10 to about 60 seconds , or about 10 to about 40 seconds , and most preferably is about 10 to 30 seconds . in one particular embodiment the palonosetron is supplied in vials that comprise 5 ml . of solution , which equates to about 0 . 25 mg of palonosetron at a concentration of about 0 . 05 mg / ml . the inventors have further discovered that by adjusting the formulation &# 39 ; s ph and / or excipient concentrations it is possible to increase the stability of palonosetron formulations . therefore , in another embodiment , the invention provides a pharmaceutically stable solution for preventing or reducing emesis comprising a ) palonosetron or a pharmaceutically acceptable salt thereof ; and b ) a pharmaceutically acceptable carrier , at a ph from about 4 . 0 to about 6 . 0 . similarly , in another embodiment the invention provides a method of formulating a pharmaceutically stable solution of palonosetron comprising admixing a ) palonosetron or a pharmaceutically acceptable salt thereof ; and b ) a pharmaceutically acceptable carrier , at a ph from about 4 . 0 to about 6 . 0 . in alternative embodiments , the ph is from about 4 . 5 to about 5 . 5 , and most optimally about 5 . 0 . there are many examples to those of skill in the art of suitable solutions to adjust the ph of a formulation . two exemplary solutions are sodium hydroxide and hydrochloric acid solution , either of which could be used to adjust the ph of the formulation . in another embodiment the invention provides a pharmaceutically stable solution for preventing or reducing emesis comprising from about 0 . 01 to about 5 . 0 mg / ml palonosetron or a pharmaceutically acceptable salt thereof and ( i ) from about 10 to about 100 millimoles citrate buffer , and / or ( ii ) from about 0 . 005 to about 1 . 0 mg / ml edta . similarly , in another embodiment the invention provides a method of formulating a pharmaceutically stable solution of palonosetron comprising admixing from about 0 . 01 to about 5 . 0 mg / ml palonosetron or a pharmaceutically acceptable salt thereof and ( i ) from about 10 to about 100 millimoles citrate buffer , and / or ( ii ) from about 0 . 005 to about 1 . 0 mg / ml edta . the citrate buffer can be in the form of citric acid and / or a salt of citric acid such as trisodium citrate . in various embodiments , the ranges of one or more of the foregoing ingredients can be modified as follows : the formulation may comprise palonosetron or a pharmaceutically acceptable salt thereof in a concentration from about 0 . 02 mg / ml to about 1 . 0 mg / ml , from about 0 . 03 mg / ml to about 0 . 2 mg / ml palonosetron hydrochloride , and most optimally about 0 . 05 mg / ml . the formulation may comprise citrate buffer in a concentration of from about 10 to about 40 millimoles , or 15 - 30 millimoles . the formulation may comprise edta in a concentration of from about 0 . 005 mg / ml to about 1 . 0 mg / ml , or about 0 . 3 to about 0 . 7 mg / ml , and most optimally about 0 . 5 mg / ml . the inventors have further discovered that the addition of mannitol and a chelating agent can increase the stability of palonosetron formulations . therefore , in still another embodiment the invention provides a pharmaceutically stable solution for preventing or reducing emesis comprising a ) palonosetron or a pharmaceutically acceptable salt thereof and b ) a pharmaceutically acceptable carrier , wherein the pharmaceutically acceptable earner comprises a chelating agent and mannitol . similarly in another embodiment the invention provides a method of formulating a pharmaceutically stable solution of palonosetron comprising admixing a ) palonosetron or a pharmaceutically acceptable salt thereof and b ) a pharmaceutically acceptable carrier , wherein the pharmaceutically acceptable carrier comprises a chelating agent and mannitol . the chelating agent is preferably edta , and , in various embodiments the chelating agent is present in a concentration of from about 0 . 005 to about 1 . 0 mg / ml or from about 0 . 05 mg / ml , to about 1 . 0 mg / ml or from about 0 . 3 to about 0 . 7 mg / ml , or most optimally about 0 . 5 mg / ml . in various embodiments the mannitol is present in a concentration of from about 10 . 0 mg / ml to about 80 . 0 mg / ml , from about 20 . 0 mg / ml to about 60 . 0 mg / ml , or from about 40 . 0 to about 45 . 0 mg / ml . injectable formulations are typically formulated as aqueous solutions in which water is the primary excipient . oral formulations will differ from injectable formulations generally by the additional presence of flavoring agents , coloring agents , or viscosity agents . natural or synthetic sweeteners include , among others , mannitol , sorbitol , saccharose , saccharine , aspartame , acelsulphame k , or cyclamate . these agents are generally present in concentrations in excess of 100 mg / ml or 250 mg / ml when used as sweetening agents , in contrast to the 41 . 5 mg / ml concentration of mannitol described in some of the embodiments of the invention , in which mannitol is acting simply as a tonicifying agent . the formulations of the present invention are particularly suited for use in injectable and oral liquid formulations , but it will be understood that the solutions may have alternative uses . for example , they may be used as intermediates in the preparation of other pharmaceutical dosage forms . similarly , they may have other routes of administration including intranasal or inhalation . injectable formulations may take any route including intramuscular , intravenous or subcutaneous . still further embodiments relate to improvements in the ease with which the palonosetron formulation can be stored or manufactured . in particular , the inventors have discovered that the formulations of the present invention allow storage of the product for extended periods at room temperature . thus , in yet another embodiment the invention provides a method of storing one or more containers in which are contained a solution of palonosetron or a pharmaceutically acceptable salt thereof comprising : a ) providing a room comprising said one or more containers ; b ) adjusting or maintaining the temperature of the room at greater than about ten , 15 , or 20 degrees celcius ; and e ) storing said containers in said room for one month , 3 months , 6 months , one year , 18 months , 24 months or more ( but preferably not exceeding 36 months ), wherein ( i ) the palonosetron or pharmaceutical salt thereof is present in a concentration of from about 0 . 01 mg / ml to about 5 . 0 mg / ml , ( ii ) the ph of the solution is from about 4 . 0 to about 6 . 0 , ( iii ) the solution comprises from about 0 . 01 to about 5 . 0 mg / ml palonosetron or a pharmaceutically acceptable salt thereof , from about 10 to about 100 millimoles citrate buffer and from about 0 . 005 to about 1 . 0 mg / ml edta , ( iv ) the solution comprises a chelating agent , or ( v ) the solution comprises from about 10 to about 100 millimoles of a citrate buffer . the stability of the foregoing formulations also lends itself well to terminal sterilization processes in the manufacturing process . therefore , in still another embodiment the invention provides a method of filling a container in which is contained a solution of palonosetron or a pharmaceutically acceptable salt thereof comprising : a ) providing one or more sterile open containers ( preferably 5 ml . vials ); b ) filling said containers with a solution of palonosetron in a non - aseptic environment ; c ) sealing said filled containers ; and d ) sterilizing said sealed , filled containers , wherein ( i ) the palonosetron or pharmaceutical salt thereof is present in a concentration of from about 0 . 01 mg / ml to about 5 mg / ml , ( ii ) the ph of the solution is from about 4 . 0 to about 6 . 0 , ( iii ) the solution comprises from about 0 . 01 to about 5 . 0 mg / ml palonosetron or a pharmaceutically acceptable salt thereof , from about 10 to about 100 millimoles citrate buffer and from about 0 . 005 to about 1 . 0 mg / ml edta , ( iv ) the solution comprises a chelating agent , or ( v ) the solution comprises from about 10 to about 100 millimoles of a citrate buffer . a study was conducted to determine the effect of ph on formulations containing palonosetron hydrochloride , measuring the stability at 80 ° c . at ph 2 . 0 , 5 . 0 , 7 . 4 , and 10 . 0 . the results indicated that palonosetron hydrochloride is most stable at ph 5 . 0 . a formulation optimization study was performed using an experimental design software . twenty - four lots of drug product were analyzed to investigate the appropriate concentration ranges for palonosetron hydrochloride ( 0 . 05 mg / ml , to 5 . 0 mg / ml ), citrate buffer ( 0 to 80 mm ) and edta ( 0 to 0 . 10 %). the level of edta and citrate buffer were selected based on the optimal formulation , which was shown to be formulated with edta 0 . 05 % and 20 mm citrate buffer at ph 5 . 0 . the results of this study indicated that palonosetron concentration was also a critical factor in chemical stability , with greatest stability seen at the lowest palonosetron concentrations . formulations of palonosetron hydrochloride in citrate buffer were prepared including either a ) sodium chloride or b ) mannitol . the palonosetron hydrochloride formulation including mannitol showed superior stability . the optimum level of mannitol required for an isotonic solution was found to be 4 . 15 %. the following is a representative pharmaceutical formulation containing palonosetron that is useful for intravenous formulations , or other liquid formulations of the drug . the following is a representative pharmaceutical formulation containing palonosetron that is useful for oral formulations , or other liquid formulations of the drug . the physical and chemical stability of palonosetron hcl was studies in concentrations of 5 μg / ml and 30 μg / ml in 5 % dextrose injection , 0 . 9 % sodium chloride injection , 5 % dextrose in 0 . 45 % sodium chloride injection , and dextrose 5 % in lactated ringer &# 39 ; s injection . the admixtures were evaluated over 14 days at 4 ° c . in the dark and for 48 hours at 23 ° c . under fluorescent light . test samples of palonosetron hcl were prepared in polyvinyl chloride ( pvc ) bags of the infusion solutions at concentrations of 5 and 30 μg / ml . evaluations for physical and chemical stability were performed on samples taken initially and after 1 , 3 , 5 , 7 , and 14 days of storage at 4 ° c . and after 1 , 4 , 24 , and 48 hours at 23 ° c . physical stability was assessed using visual observation in normal room light and using a high - intensity monodirectional light beam . in addition , turbidity and particle content were measured electronically . chemical stability of the drug was evaluated by using a stability - indicating high performance liquid chromatographic ( hplc ) analytical technique . all samples were physically stable throughout the study . the solution remained clear , and little or no change in particulate burden and haze level were found . additionally , little or no loss of palonosetron hcl occurred in any of the samples at either temperature throughout the entire study period . the physical and chemical stability of palonosetron hcl 0 . 25 mg admixed with dexamethasone ( as sodium phosphate ) 10 mg or 20 mg in 5 % dextrose injection or 0 . 9 % sodium chloride injection in polyvinyl chloride ( pvc ) minibags , and also admixed with dexamethasone ( as sodium phosphate ) 3 . 3 mg in 5 % dextrose injection or 0 . 9 % sodium chloride injection in polypropylene syringes at 4 ° c . in the dark for 14 days and at 23 ° c . exposed to normal laboratory fluorescent light over 48 hours , was studied . test samples of palonosetron hcl 5 μg / ml with dexamethasone ( as sodium phosphate ) 0 . 2 mg / ml and also 0 . 4 mg / ml were prepared in polyvinyl chloride ( pvc ) minibags of each infusion solution . additionally , palonosetron hcl 25 μg / ml with dexamethasone ( as sodium phosphate ) 0 . 33 mg / ml in each infusion solution were prepared as 10 ml of test solution in 20 - ml , polypropylene syringes . evaluations for physical and chemical stability were performed on samples taken initially and after 1 , 3 , 7 , and 14 days of storage at 4 ° c . and after 1 , 4 , 24 , and 48 hours at 23 ° c . physical stability was assessed using visual observation in normal room light and using a high - intensity monodirectional light beam . in addition , turbidity and particle content were measured electronically . chemical stability of the drug was evaluated by using a stability - indicating high performance liquid chromatographic ( hplc ) analytical technique . all samples were physically compatible throughout the study . the solutions remained clear , and little or no change in particulate burden and haze level were found . additionally , little or no loss of palonosetron hcl and dexamethasone occurred in any of the samples at either temperature throughout the entire study period . this invention has been described with reference to its preferred embodiments . variations and modifications of the invention will be obvious to those skilled in the art from the foregoing detailed description of the invention .
the present invention relates to shelf - stable liquid formulations of palonosetron for reducing chemotherapy and radiotherapy induced emesis with palonosetron . the formulations are particularly useful in the preparation of intravenous and oral liquid medicaments .