Ocular system made of bioerodible esters having linear ether

Claim 1

An ophthalmic dosage form comprising solid particles of from 0.01 up to 20 parts of an ophthalmic drug admixed with from 0.01 up to 30 parts of a bioerodible drug release rate-controlling orthoester homopolymer of the general formula: ##STR6## wherein R 1 is a member selected from the group consisting of alkylene of 4 to 12 carbons, a cycloalkylene of 5 to 6 carbons, and an alkyleneoxy of 1 to 7 carbons, R 2 is a lower alkyl of 1 to 7 carbons, a is 0 to 1, and n is greater than 10, said solid particles from 10 to 300 microns in largest dimensions, non-irritating and non-toxic to the eye, with from 1 to 5 parts of said solid particles admixed with a suspension agent and up to 100 parts of an ophthalmically-acceptable liquid medium having a pH acceptable to the eye, and when said liquid dosage form is dispensed to an eye, the solid particles bioerde in response to the environment of the eye at a controlled rate and administer drug over a prolonged period of time.