Development, characterization, and evaluation of ketorolac tromethamine-loaded biodegradable microspheres as a depot system for parenteral delivery.

Ketorolac tromethamine, a potent nonnarcotic analgesic agent and 800 times more potent than aspirin, is indicated for the short-term management of moderate to such severe painful states as post operative pain, acute musculoskeletal pain, and dental pain. It Given every 6 hr intramuscularly in patients for acute pain, to avoid frequent dosing and patient inconvenience Ketorolac from ethamine was found suitable for parenteral depot system by biodegradable microspheres for the present study. Ketorolac tromethamine-loaded microspheres were prepared by o/w emulsion solvent evaporation technique using different polymers viz. polycaprolactone, poly-dl-lactide (Resomer) and poly lactic acid (PLA). To tailor the release profile of drug for several days, blends of Resomer and PLA were prepared with polycaprolactone in different ratios. Higher encapsulation efficiency was obtained with microspheres made with pure Resomer. Surface topography was studied by scanning electron microscopy, which showed spherical shape of microspheres. Residual solvent analysis was carried out to determine the residual amount of dichloromethane in microspheres and the content was found within permissible limits. Differential scanning calorimetric studies also were carried out to study any drug polymer interactions. We concluded that with careful selection of different polymers and their combinations, we can tailor the release of ketorolac tromethamine for long periods.