Pharmaceutical composition for sustained release of a peptide drug

Abstract

A novel pharmaceutical composition comprising a peptide drug and a polyester, for extended release of the peptide drug is claimed. The composition contains a salt formed from a cation derived from a peptide containing at least one basic group and an anion derived from a carboxy-terminated polyester and the application of such compositions is claimed for injection or sub-dermal implantation.

Polyester salts of synthetic hormones or their analogues, agonist or antagonist, are claimed. The polyester salts of the hormonal peptides and their formulations in aqueous medium give extended release of the peptide drug in vim, in excess of three months or more. Measurement of blood levels of hormone indicate sustained drug release for several weeks. Formulations of goserelin polyester salt when given subcutaneously to regularly cycling adult female rats (3.6 mg goserelin per rat) gave periods of goserelin release in excess of six weeks to three months or more.

Salts of substance P gave continuous release of the peptide for a period of about four weeks. A composition is claimed wherein the peptide is pharmacologically active e.g., synthetic hormones, or pharmacologically inactive e.g., polymers or copolymers of basic or neutral amino acids. The polyester is selected from those derived from the polycondensation of hydroxy acids with dicarboxylic acids.