Biodegradable ortho-ester polymers - for enclosing active agents to be liberated therefrom e.g. steroid implants

摘要

Polymers contain the repeating unit of formula (I) (where R1 is a polyvalent racical of (a) 2-10C alkylene or alkenylene; (b) 2-6C oxa-alkylene with one or two internal oxa gps.; (c cycloalkylene contg. 3-7 cyclic C atoms and opt. substd. by 1-7C alkyl or alkoxy or 2-7C alkinyl; (d) cycloalkenylene contg. 4-7 cyclic C atoms and opt. substd. as in (c); (e) cycloalkene-di(aliphatic hydrocarbylene) contg. 3-7 cylic C atoms, the hydrocarbylene gps. contg. 1-7C atoms and the ring being opt. substd. as in (c); (f) cycloalkane-di(aliphatic hydrocarbylene) contg. 4-7 cyclic C atoms. Matl. is used e.g. as a biodegradable polymer enclosing an active agent which is liberated therefrom, e.g. pesticides, herbicides, biocides, algicides, rodenticides, fungicides, insecticides, cosmetic prods., medicaments, fertility inhibitors and activators, air purifiers, nutritive substances, etc. The active substance may be liberated at constant or variable rates depending on the compsn. and m. wt. of the polymers. The polymers are esp. suitable for the prepn. of steroid implants for the treatment of inflammations.