Formulation development, in vitro and in vivo evaluation of microemulsion-based gel loaded with ketoprofen

Background: Anti-inflammatory agents are widely used to relieve inflammation caused by various factors. Aim: This study was initiated with the intention to deliver low aqueous soluble ketoprofen to enhance its solubility by developing microemulsion system as a template and then incorporating it into gel phase. Materials and methods: Initially ketoprofen was solubilized into microemulsion preparation made up of clove oil, Tween 20 and propylene glycol as oil phase, surfactant and co-surfactant respectively, then it was incorporated into different concentration of gelling phase using gelling agents namely Carbopol 940, Carbopol 934 and hydroxypropyl methyl cellulose K4M (HPMC K4M). Formulated emulgels were evaluated for their physical appearance, pH, rheological properties, globule size, extrudability, drug content, spreadability, bioadhesion strength, in vitro and ex vivo drug release, skin irritation test and anti-inflammatory activity. Results: Microemulsion had shown globule size 396 nm, pH 6-6.7, viscosity 29.4 cps and zeta potential -12mV indicating good stability. Formulated emulgels showed good physical appearance, skin acceptable pH 6-6.9, non-Newtonian shear thinning system, drug content 99.28 +/- 0.16%, bioadhesion strength 48.4 gram force, globule size 473 nm, spreadability 22.96 gm.cm/s, good extrudability, in vitro release, ex vivo release did not showed any irritation reaction and possess a good anti-inflammatory activity. Conclusions: Selected batch showed enhanced drug release (92.42 +/- 4.66%) as compared to marketed gel (65.94 +/- 3.30). Similarly ex vivo release of formulation showed 72.22% release through mice skin compared with marketed gel. Formulations followed Korsmeyer-Peppas diffusion kinetic model. It was observed from the results that the formulated emulgel can provide promising delivery of ketoprofen.