Omega 3 fatty acid-enriched nanoemulsion of thiocolchicoside for transdermal delivery: formulation, characterization and absorption studies.

Thiocolchicoside (TCC) is an effective therapeutic agent against the orthopaedic, traumatic and rheumatologic disorders but it suffer from the drawback of poor bioavailability due to extensive first pass metabolism and low permeability via the oral route. The aim of the present study was to evaluate the potential of nanoemulsion (NE) for bioavailability enhancement of TCC through the transdermal route. The NEs were developed using Linseed: sefsol in 1:1 ratio as the oil phase, span 80, Transcutol P and distilled water as surfactant, co-surfactant and aqueous phase. Furthermore, selected formulations were subjected to physical stability and consequently evaluated for in vitro permeation using porcine skin. The optimized formulation had small average globule diameter of 117 nm with polydispersity index of 0.285. The globules were spherical in shape as observed by transmission electron microscopy. The in vitro skin permeation profile of optimized NE was compared with aqueous solution of TCC. Significant increase in permeability parameters were observed in NEs formulation (p < 0.05) as compared to aqueous solution of TCC. The steady-state flux (Jss) and permeability coefficient (Kp) for optimized NE formulation (C1) were found to be 30.63 ± 4.18 µg/cm(2)/h and 15.21 × 10(-3) ± 2.81cm(2)/h, respectively. The results of enhanced permeation through transdermal route suggest that water-in-oil NEs which are compatible with the lipophilic sebum environment of the hair follicle facilitate the transport of TCC, and such transport might be predominantly transfollicular in nature. Overall, these results suggested that water-in-oil NEs are good carriers for transdermal delivery of TCC.