Purpose: Melatonin (MLT) could be candidate drug for treatment of several diseases because of its high antioxidant and anticarcinogenic activity and its important biological roles. The aim of this study was to assess the influence of different vehicles on the permeation of MLT through buccal and skin tissues.
Methods: Formulations were characterized in terms of rheology, drug release and permeation through human skin as well as porcine buccal mucosa. Irradiation experiments were also performed.
Results: The lowest amount of MLT released was from oral adhesive paste Orabase® (OB) and the highest from the emulsion system Montanov® 68 (M68). Skin permeation revealed high pattern for Carbopol® 940 (C940) and M68, and poor for poloxamer 407 (P407) and Pluronic® lecithin organogel (PLO). Statistical differences of MLT remaining in skin between M68 vs C940 (p < 0.05) and M68 vs PLO (p < 0.05) were observed. Transmucosal results showed that sodium carboxymethylcellulose (NaCMC) was the best and OB the worst vehicle. P407 and PLO followed similar behaviour. Photostability studies revealed high percentage of degradation of MLT in solution which was also similar when was loaded in OB. The rest of formulations showed low rates of degradation.
Conclusions: C940 or M68 and NaCMC can be proposed as formulations for a potential systemic effect of MLT by skin and buccal mucosa routes, respectively. However, if the intended objective is to obtain local action in the skin and buccal mucosa, the proposed formulations are M68 or P407 and PLO.
Keywords: absorption; buccal mucosa; melatonin; retention; skin.