Sustained release of isoniazid in vivo from a single implant of a biodegradable polymer.

In order to solve the problem of poor patient compliance, attempts were made to prolong the bioavailability of antimycobacterial drugs after a single administration. A single implant of polylactic-co-glycolic acid (PLGA) co-polymer containing isoniazid ensured its sustained release up to 6 weeks. The levels are comparable with those obtained from daily doses. Homogenates of liver and lungs from animals killed at 6 weeks after a single implant showed high antimycobacterial activity against Mycobacterium tuberculosis. Sera from the implant and daily dose group animals showed no significant difference in renal, hepatic and haematological parameters. The implant caused no local or systemic toxicity.