Claims for Patent: 4,997,651

Summary for Patent: 4,997,651

Title:	Pharmaceutical formulations
Abstract:	The present invention relates to a new two-component pharmaceutical formulation of melphalan in which the two components comprise (a) freeze-dried mephalan hydrochloride and (b) a solvent-diluent comprising a citrate, propylene glycol and ethanol. Substantially pure melphalan, substantially pure melphalan hydrochloride and methods for preparing them are also described.
Inventor(s):	Poole; Stephen W. (Dartford, GB2), Stanley; Timothy P. (Dartford, GB2), Divall; Geoffrey (Dartford, GB2), Packham; Terence W. (Dartford, GB2), Knight; Joseph (Dartford, GB2)
Assignee:
Application Number:	07/273,227
Patent Claims:	1. A pharmaceutical formulation of melphalan comprising as two separate components (a) freeze-dried melphalan hydrochloride, and (b) a solvent-diluent comprising a citrate, propylene glycol and ethanol. 2. A pharmaceutical formulation according to claim 1 wherein component (a) includes a non-hydroxylated matrix-forming agent. 3. A pharmaceutical formulation according to claim 2 wherein the non-hydroxylated matrix-forming agent is polyvinylpyrrolidone. 4. A pharmaceutical formulation according to claim 1 wherein the citrate is an alkali metal citrate. 5. A method for preparing a pharmaceutical formulation of melphalan which comprises formulating as two separate components (a) freeze-dried melphalan hydrochloride and (b) a solvent-diluent comprising a citrate, propylene glycol and ethanol. 6. A pharmaceutical formulation according to claim 1, wherein the melphalan hydrochloride is in substantially pure form. 7. A pharmaceutical formulation according to claim 6, wherein the substantially pure melphalan hydrochloride is prepared by heating a mixture of melphalan and hydrogen chloride in a C.sub.2-4 alkanol for up to five minutes and cooling to effect crystallization of melphalan hydrochloride. 8. A pharmaceutical formulation according to claim 6, wherein the melphalan hydrochloride is prepared by reacting ethyl N-phthaloyl-p-amino-L-phenylalnine or an acid addition salt thereof with ethylene oxide such that the reaction temperature does not exceed 35.degree. C. followed by the steps of chlorination and hydrolysis and conversion into the hydrochloride salt. 9. A pharmaceutical formulation according to either claim 2 or claim 3, wherein the matrix-forming agent constitutes 20-95% by weight of component (a). 10. A pharmaceutical formulation according to claim 4, wherein the alkali metal citrate is selected from sodium and potassium citrate. 11. A pharmaceutical formulation according to claim 1, wherein component (b) contains 40-80% by volume of propylene glycol. 12. A pharmaceutical formulation according to claim 1, wherein component (b) contains 0.1-10% by volume of ethanol. 13. A pharmaceutical formulation according to claim 1, wherein component (b) contains 0.05-5% w/v of the citrate. 14. A pharmaceutical formulation according to claim 1, in the form of a unit dose containing from 1-100 mg of melphalan and from 1-50 ml of solvent-diluent. 15. A pharmaceutical formulation according to claim 14, containing 10 mg of melphalan and 10 ml of solvent-diluent. 16. A pharmaceutical formulation according to claim 14, containing 50 mg of melphalan and 10 ml of the solvent-diluent.