SUSTAINED RELEASE ARTEMETHER-LOADED SOLID LIPID MICROPARTICLES, BASED ON SOLIDIFIED REVERSE MICELLAR SOLUTION (SRMS)

Objectives: To prepare and evaluate sustained release artemether-loaded SLMs based on SRMS Material and methods: SRMS, consisting of mixtures of Phospholipon® 90H (P90H) and Softisan® 154 (1:1, 2:1 and 1:2) were formulated and characterized using differential scanning calorimetry (DSC). The SRMS were used to formulate artemether-loaded SLMs by melt homogenization. The SLMs were characterized based on particle size and morphology, pH stability, encapsulation efficiency (EE%) and loading capacity. In vitro release was carried out in simulated intestinal fluid (SIF, pH 7.5). Results: Thermograms of the SRMS (1:1, 2:1 and 1:2) showed sharp endothermic peaks at 65.5, 64.4 and 62.3 oC respectively. Maximum EE% of 70.00 ± 1.50 % was obtained for SLMs formulated with SRMS 1:1 and 1 % artemether. Loading capacity ranged from 5.67 to 17.90 g drug/100 g lipid. In vitro release showed about 80 to 84 % drug release at 7 h. Particle size of artemether-loaded SLMs ranged from 18.60 ± 0.09 to 34.80 ± 0.30 µm. The pH decreased significantly at 60 days from 6 to 4.8 for batch A2 formulated with SRMS 2:1 and 3 % artemether (p < 0.05). Conclusion: artemether-loaded SLMs based on SRMS had good sustained release properties and could be used once daily in order to enhance patient's compliance.  Key words: Malaria, artemether, SRMS, lipids, sustained release SLMs Â