Optimization of formulation processes using Design Expert® Software for preparation of polymeric blends-artesunate-amodiaquine HCl microparticles


A 23 Factorial design of cissus-gelatin B polymer blends was developed to formulate amodiaquine HCl-artesunate (AQ-AS) microparticles by varying the polymer blend concentration (2 %w/v, 5 %w/v), crosslinking time (0.5 h, 1 h) and glutaraldehye volume (0.5 ml, 1 ml). The formulations were evaluated using drug entrapment efficiency (EE), particle size, polydispersity index, thermal behaviour with differential scanning calorimetry, crystallinity with powder X-ray diffraction, morphology with scanning electron microscope and in vitro release using combination of simulated gastric fluid (SGF, pH = 7.4, 95%) and methanol (5%). The expected responses, EE and in vitro release were fitted into Design Expert®.

The polymer blends exhibited pseudoplastic behavior and there was no marked change in rheology behaviour of 2% w/v dispersion at 55 °C. The AQ-AS formulated microparticles were dark brownish discrete mass, physically stabilized, irregular shape, polydisperse, and partially crystalline system. An optimal formulation comprising polymer blend (5 %w/v), glutaraldehyde (1 ml) and cross-linking time (0.5 h) was identified to provide desired values for EE, amodaquine HCl (47.41%), artesunate (36.42%) and in vitro release. This study proposes the best opportunity for selection of factors required for optimum microparticles formulation using the polymer blends and the drugs.