Controlled drug release from bioerodible hydrophobic ointments.

A new type of poly (ortho ester) was prepared by the condensation of a triol and an alkyl ortho ester. The condensation produces polymers that are viscous pastes at r.t. even though molecular weights in excess of 50,000 dalton can be produced. Such materials are useful as bioerodible drug delivery devices because rate of release of an incorporated therapeutic agent can be controlled by the addition of small amounts of acidic excipients to the polymer. A significant advantage of these materials is that therapeutic agents can be incorporated by simple mixing at r.t. without the use of solvents.