Original Articles
Kenneth Maduabuchi Ezealisiji,
Abstract
The in vitro study of skin permeability plays a vital role in the selection of candidates for the development of transdermal dosage forms. In this work, mirtazapine nanoemulsions were developed, characterized and the pharmacokinetics were studied. Nanoemulsions were prepared using the spontaneous emulsification mechanism. Surfactant (sodium lauryl sulfate) and cosurfactant (propylene glycol) were mixed in different volume ratios. Pseudoternary phase diagrams were developed using the aqueous titration method. Nanoemulsions formed were characterized by particle size, polydispersity index, and zeta potential. Analysis of variance (ANOVA) of data was evaluated and optimized nanoemulsions with Smix ratio of (3:1) were obtained. The zeta potentials of the optimized nanoemulsions were –94.000±0.001 and -92.900±0.004 mV for nanoemulsion formulation 16 (NE16) and nanoemulsion formulation 17 (NE 17) respectively, while mean droplet size (photon correlation microscopy) for the same optimized formulations were 56.00±0.01, 24.00±0.01 nm respectively. There was good correlation between mean droplet size result obtained from PCS and the values obtained using transmission electron microscope (46.0 ± 12.15 and 38.2 ± 7.62 nm respectively). The in vitro skin permeation study using excised rat skin showed the permeability coefficient values for the optimized nanoemulsions to be 0.0284±0.005 and 0.0332±0.002 cm/h for formulations NE 16 and NE 17 respectively, while that of the control (mirtazapine suspension in distilled water) was 0.0019±0.003 cm/h. The relative bioavailability was observed to be 79.17 % and 44.38 % compared to the calculated 16.80 % for the oral suspension thus making the developed Nanoemulsion more potent than previous oral formulations.