the invention relates to an injectable composition for the extended release of aripiprazole comprising a mixture of aripiprazole in an injection vehicle comprising an optional viscosity enhancing agent . the aripiprazole can be present in an amount of at least about 10 mg / ml , preferably at least about 20 mg / ml or at least about 30 mg / ml . the invention also relates to methods for providing aripiprazole to an individual in an extended release injectable composition comprising administering a mixture of at least about 50 mg aripiprazole in an injection vehicle . in general , the aripiprazole will be suspended in the injection vehicle . in one embodiment , the aripiprazole is supplied in a free flowing powder , substantially free of major amounts of pharmaceutical excipients or other compounds . for example , the aripiprazole can be supplied in a micronized state , consisting of or consisting essentially of aripiprazole . an aripiprazole drug substance can be said to consist essentially of aripiprazole if it contains , for example , 90 % by weight or more aripiprazole and minor amounts ( e . g ., less than 10 % by weight ) of other materials that are , for example , residual to its process for manufacture . compounds that may be found in a substantially pure aripiprazole drug substance can include wetting agents used , for example , to facilitate micronization , grinding or comminution , residual solvents , reaction by products or staring materials . the compositions of the present invention are free of sustained release matrices . sustained release matrices are polymers and other macromolecules ( albumin ), present in major amounts ( e . g ., 50 % by weight or more of total solids ), which when the active agent is dispersed therein , are used to slow the exposure or bioavailability of the active agent in the patient . a frequently used polymeric matrix is poly lactide - co - glycolide polymers . thus , the aripiprazole drug substance and / or injectable compositions of the invention generally do not contain major amounts of plga polymer matrices . of course , polymers are often found in pharmaceutical compositions where the activity is not at all related to extending the release profile of the drug . for example , minor amounts of polysorbates , polyamines , polyvinylalcohol and polyethylene glycols are added to facilitate dispersibility of active agents in its vehicles . the inclusion of such polymers in amounts intended to accomplish these functions , and in amounts that do not permit the formation of substantial matrix formation , is permitted . the aripiprazole drug substance is added to an injection vehicle . the drug substance can be dispersed or suspended in the vehicle , depending upon the solubility of the drug in the vehicle . the vehicle is preferably an aqueous vehicle which suspends the drug substance . preferably , the vehicle contains a viscosity enhancing agent . viscous vehicles can have , for example , a viscosity of at least 20 cp at 20 ° c . in other embodiments , the fluid phase of the suspension has a viscosity at 20 ° c . of at least about 30 cp , 40 cp , 50 cp , and 60 cp are preferred . the viscosity can be achieved by adding a viscosity enhancing agent , such as a carboxymethyl cellulose , such as sodium carboxy methylcellulose . in one embodiment , the injection vehicle comprises at least about 1 % by volume sodium carboxymethyl cellulose , preferably about 3 % by volume carboxymethyl cellulose . the injection vehicle can advantageously contain a wetting agent , such as a polysorbate . suitable polysorbates include polysorbate 20 , polysorbate 40 , and polysorbate 80 , sold under the trademark tween ®. the wetting agent can be added in an amount that enhances the dispersibility of the active agent . an example of a suitable amount includes about 0 . 1 to 2 % by weight of polysorbate 20 . the injection vehicle can also advantageously employ a density enhancing agent , such as a sugars , e . g . mannitol , or sorbitol and / or a tonicity adjusting agent , such as sodium chloride . in one embodiment , the tonicity adjusting agent is about 1 % by weight , including 0 . 9 % by weight . in one embodiment , the composition consists of the aripiprazole drug substance and the injection vehicle , thereby providing a surprisingly simple and elegant formulation for obtaining an extended or sustained release profile . the aripiprazole drug substance can comprise , consist essentially of or consist of aripiprazole ( in a crystalline , non - crystalline or amorphous form ), an aripiprazole salt , an aripiprazole solvate ( including ethanolates and hydrates ), or other aripiprazole polymorphs . preferred salts include those salts insoluble in an aqueous vehicle . pharmaceutical salts such as the hydrochloride and hydrobromide salts are suitable . the methods of the invention include administering the compositions described herein , thereby obtaining an extended release or sustained release profile in the patient . an extended release profile includes deliveries that achieve a therapeutically effective amount of the aripiprazole is present in the plasma of the individual for at least about 7 days , preferably at least about 14 days , or more preferably at least about 21 days alternatively for at least 2 , 3 , 4 , 6 or 8 weeks or as much as three months . in one embodiment , the formulations can be administered as a single or sole dose . however , the invention is particularly beneficial for those individuals that require constant or chronic therapy , such as those that receive repeated doses over several weeks or months or more . in such dosing regimens , the method can comprise a first administration of a first extended release formulation and a second administration of a second extended release formulation . the second formulation can be the same , substantially the same or different as the first and can include the same active agent or a different active agent . for example , the second formulation can be administered at about 7 days , or more , such as at least about 14 days , or at least about 17 days , after the first administration , where the first administration results in the release of agent for a period of 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 days , or more . the term “ therapeutically effective amount ” is further meant to define an amount resulting in the improvement of any parameters or clinical symptoms . the actual dose may vary with each patient and does not necessarily indicate a total elimination of all disease symptoms . as used herein , the term “ individual ”, “ subject ” or “ patient ” refers to a warm blooded animal , including but not limited to humans , such as a mammal which is afflicted with a particular disease state . a therapeutically effective amount of the compound used in the treatment described herein can be readily determined by the attending diagnostician , as one skilled in the art , by the use of conventional techniques and by observing results obtained under analogous circumstances . in determining the therapeutically effective dose , a number of factors are considered by the attending diagnostician , including , but not limited to : the species of mammal ; its size , age , and general health ; the specific disease involved ; the degree of or involvement or the severity of the disease ; the response of the individual patient ; the particular compound administered ; the mode of administration ; the bioavailability characteristic of the preparation administered ; the dose regimen selected ; the use of concomitant medication ; and other relevant circumstances . the mode of administration will generally be by injection or implantation , such as intramuscularly or subcutaneously . preferred amounts according to the selected mode of administration are able to be determined by one skilled in the art . pharmaceutical compositions can be manufactured utilizing techniques known in the art . typically the therapeutically effective amount of the compound will be admixed with a pharmaceutically acceptable carrier . for injection , the compounds may be in a physiologically acceptable pharmaceutical carrier and administered as a suspension . illustrative pharmaceutical carriers also include water , aqueous methylcellulose solutions , saline , dextrose solutions , fructose solutions , ethanol , or oils of animal , vegetative , or synthetic origin . the pharmaceutical carrier may also contain preservatives , and buffers as are known in the art . when the composition is to be used as an injectable material , including but not limited to needle - less injection , it can be formulated into a conventional injectable carrier . suitable carriers include biocompatible and pharmaceutically acceptable solutions . in a preferred embodiment , the size of the drug particle can be controlled . often , the mass mean diameter of the drug particles is less than 100 microns , such as between about 1 and 100 microns , preferably about 10 and 100 microns , or about 20 and 60 microns . in one embodiment , the unit dosage form can be stored as a dry powder , for example , to be mixed for injection prior to use , or as a stable suspension ready for use . other methods for storing or administration using art recognized methods are also contemplated herein . pharmacokinetic evaluation of aripiprazole in rats following administration of single subcutaneous doses of aripiprazole formulations group a : three rats injected once sc with 10 mg of aripiprazole . group b : three rats injected once sc with 20 mg of aripiprazole . group c : three rats injected once sc with 30 mg of aripiprazole . group d : three rats injected once sc with ˜ 67 mg of microparticles . group e : three rats injected once sc with ˜ 40 mg of microparticles . blood collection blood samples were collected via a lateral tail vein after anesthesia with halothane . a syringe without an anticoagulant was used for the blood collection , then the whole blood was transferred to tubes containing k2 edta and mixing beads ( microtainer ®; mfg # bd365974 ). the blood samples were processed ( the tubes are inverted 15 - 20 times and centrifuged for 2 minutes at & gt ; 14 , 000 g &# 39 ; s ) to separate plasma . the plasma samples prepared in this manner were transferred to labeled plain tubes ( microtainer ®; mfg # bd5962 ) and stored frozen at & lt ;− 70 ° c . blood volumes : at least 250 μl blood were collected at for each time point during the first 24 hours and 400 μl for at each time point thereafter . note : when plasma concentration was lower than the limitation of quantification , that group of ats were terminated . the results obtained are reported in the figure . surprisingly , the rats that received bolus injections of aripiprazole and injection vehicle alone were substantially the same as those that received the aripiprazole dispersed within a plga microsphere . modifications and variations of the invention will be obvious to those skilled in the art from the foregoing detailed description of the invention . such modifications and variations are intended to come within the scope of the appended claims . all patents , patent application publications and articles cited herein are incorporated by reference in their entirety .
the present invention relates , in part , to the discovery that a pharmaceutical composition comprising aripiprazole and a carrier administered in a bolus injection resulted in an extended release profile similar to that obtained by the injection of a poly lactide - co - glycolide microsphere formulation containing the active agent . this surprising result suggests that pharmacologically beneficial extended release formulations without the complexities and expense associated with the manufacture microspheres .