Evaluation of Skin Permeation and Pharmacological Effects of Tenoxicam Nanoemulsion in Topical Formulations

Abstract

This article was aimed to investigate the skin permeation, the anti-inflammatory and analgesic effect of topical formulations containing Tenoxicam in a nanoemulsion form in drug concentration 0.5% and 1%. Skin permeation study was carried out using rat abdominal skin. Two tests were employed to evaluate the pharmacological effects included the Paw Oedema induced by Carrageenan injection and Hot plate test for anti-inflammatory and analgesic effect respectively. Finally, skin irritation test was performed to confirm the safety of both formulae. The obtained results suggested that Tenoxicam in lower concentration (0.5%) gives insignificantly greater cumulative % of in-vitro rat skin permeation (41.5%) than higher concentration (1% Tenoxicam releases 40.1%) in 24 hr, this confirm that Tenoxicam may possibly permeate through the human skin. The study also revealed that group 2 (animals treated with Tenoxicam nanoemulsion 0.5% in MC gel), group 3 (animals treated with 1% Tenoxicam nanoemulsion prepared in HPMC) and group 4 (animals treated with commercial analogue (Feldene® Gel) produced maximum percent oedema inhibition after 1 hr (70.95%, 78.74% and 72.94%) respectively and then continued significantly for 3 hrs. Also the same previous animal groups showed maximum increase in reaction time [analgesic effect] after 1.5 hr (18.7, 27.6 and 21 seconds) respectively. Skin irritation test suggested that both topical formulae were non-sensitizing and safe for human topical use. Finally it was concluded that formulae containing (oleic acid 10%; Tween 20 43.33%; PG 21.66% and water 25%) nanoemulsion equivalent to 0.5% Tenoxicam in MC gel base and 1% Tenoxicam in HPMC gel base possessed a good and an acceptable in-vitro skin permeation and pharmacological effects.