Development of Biodegradable and Injectable Latices for Controlled Release of Potent Drugs

A new dosage form designed to provide parenteral drug delivery over a prolonged period of time following a standard injection has been investigated using testosterone as the model drug. The drug carrier consists of a biodegradable, biocompatible polymer in which the drug is dispersed on a molecular level. The polymer itself is formulated as a pseudolatex with high solid content (40.0%). The formulation has a low viscosity (97 cps) which can be injected easily through a hypodermic needle. The histopathology study showed good tissue compatibility of the pseudolatices and in-vivo tests on rats confirmed a prolonged release of drug over a 14 day period. The stability of the biodegradable poly-d, l-lactic acid latex was found not to be significantly changed over 120 days of storage at room temperature (25°). A six month study showed a slight increase (10%) in the viscosity of the parenteral product when stored at room temperature. The increase was attributed to partial coalescence of the polymer particles which had an initial diameter of 0.45 μm.