Preparation of novel solid lipid microparticles loaded with gentamicin and its evaluation in vitro and in vivo

Objective: To formulate and evaluate solid-reversed-micellar-solution (SRMS)-based solid lipid microparticles (SLMs) for intramuscular administration of gentamicin. Methods: SRMS formulated with Phospholipon (R) 90G and Softisan (R) 154 were used to prepare gentamicin-loaded SLMs. Characterizations based on size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release of gentamicin from the SLMs was performed in phosphate buffer while in vivo release studies were conducted in rats. Results: Maximum EE% of 90.0, 91.6 and 83.0% were obtained for SLMs formed with SRMS 1: 1, 1: 2 and 2: 1, respectively. Stable, spherical and smooth SLMs of size range 9.80 +/- 1.46 mu m to 33.30 +/- 6.42 mu m were produced. The release of gentamicin in phosphate buffer varied widely with the lipid contents. Moreover, significant (p < 0.05) amount of gentamicin was released in vivo from the SLMs. Conclusion: SRMS-based SLMs would likely offer a reliable means of delivering gentamicin intramuscularly.