Polymeric nanoparticles based topical gel of poorly soluble drug: formulation, ex-vivo and in vivo evaluation

The study was conducted to evaluate the potential application of nanocapsules and nanospheres as topical drug delivery systems for indomethacin (as model drug). Both were prepared by nanoprecipitation using poly (ɛ-caprolactone) and hydroxypropyl β-cyclodextrin polymers and evaluated for morphology, particle size, zeta potential, EE% and in vitro drug release then incorporated in methylcellulose and Carbopol 940 gel bases and evaluated for in vitro release. The selected formulations and market product were evaluated for ex vivo human skin permeation and anti-inflammatory and analgesic activities by paw edema and hot plate methods respectively. Results showed that nanocapsules had slight higher EE% and larger particle sizes than nanospheres. In vitro release and zeta potential were nearly similar. Methylcellulose exhibited higher in vitro release than Carbopol 940 after 3 h (except NS2). Ex vivo skin permeation studies showed significant higher cumulative amount of IND (and flux) from NC1/MC and NS1/MC (1573.06 ± 14.23 µg/cm2 and 1452.24 ± 23.18 µg/cm2 respectively) than market product. They also showed enhancement ratio and permeability coefficient rate of ∼1.5 and ∼2 respectively. NC1/MC proved to be significantly higher pharmacodynamic effects than market product. All results showed that NC1/MC could provide a promising formula as a topical delivery of indomethacin.