[Preparation of peroral sustained release drug forms on a base of biodegradable polymers. 1. Preparation and characterization of polylactic acid].

Biodegradable polymers get more interest for the preparation of drug formulations. Their main advantage is their physiological safety. Polylactic acid is one of the biodegradable polymers. It was prepared by the direct polyesterification of lactic acid and by polymerisation of the cyclic oligomers. Both the polymers were identified by elementary analysis, by IR spectroscopy, by X-ray-test and by the molecular mass. They differ in their molecular mass and in the degree of the crystalline state. The determination of the grain size, moisture content, flowability and of the parameters for the direct compression were carried out with regard to the use of polylactic acid as auxiliary substance for the direct compression. The results show, that polylactic acid which was prepared on the basis of polyesterification, is a very suitable auxiliary substance for the direct compression.