pharmaceutical compositions containing polymers buffered orthoester.

The present invention relates to a pharmaceutical composition for the controlled release of therapeutic agents FROM ORTHO ESTER carboxylic acid polymers. The composition comprises a pharmaceutically acceptable salt of an acid, which together with the acid R 1 -COOH OF CO MPOSICION Orto ESTER POLYMER (I) is released and forms a buffer system in a range of physiologically acceptable pH.