Formulation and evaluation of cubosomes containing colchicine for transdermal delivery.

Gout is a common inflammatory disease that is characterized by the deposition of serum urate crystals in the synovial fluids and joints. In spite of high efficiency of colchicine (COL) in treatment of gout, it has potential side effects associated with its oral administration. This study was aimed to enhance COL bioavailability and minimize associated side effects through transdermal delivery of COL-loaded cubosomes. Eight cubosomal dispersions were prepared according to Box-Behnken factorial design and the effect of COL, glyceryl monooleate (GMO), and surfactant (P407) concentrations on particle size distribution, zeta potential, and entrapment efficiency were assessed. The results revealed that the optimum formula exhibited a mean particle size of 73.07 ± 2.18 nm and entrapped 32.40 ± 2.33% of COL. The influence of transdermal application of COL cubosomal gel on the in vivo absorption of the drug was studied in rats compared with oral COL solution. The results of in vivo study showed that transdermal application of COL cubosomal gel significantly improves the drug absorption compared with oral COL solution, with evidence of a relative bioavailability of 4.6 times greater than that of oral COL solution. In conclusion, transdermal application of COL cubosomal gel may be a promising delivery system for enhancing the bioavailability of COL. Graphical abstract.