Characterization and Pharmacokinetic Evaluation of Gamma Sterilized Ketorolac Tromethamine Loaded Albumin Microspheres for Intramuscular Administration

Pharmacokinetic parameters of ketorolac tromethamine (KT) loaded albumin (KTAL) microspheres were determined using New Zealand white rabbits. Each rabbit (n=6) was injected 5 mg/kg body weight of plain KT or an equivalent dose in microsphere form in 2 mL water for injection. Prior to animal studies microspheres were tested for toxic residues and were gamma sterilized. Sterilized microspheres were evaluated for their integrity by physico-chemical characterization. Test for toxic residues was negative, the sterilization process utilized was effective and did not alter any physicochemical characteristics and showed good syringeability. When KT was administered in the form of microspheres there was a significant increase in Cmax, AUC, t1/2 and MRT (P < 0.05). When administered as microspheres, plasma concentration of drug sustained for 24 hours. It was concluded that KTAL microsphere formulation improved the systemic exposure and sustained the drug release and could be used for once-a-day administration of KT.