Development of Kaempferia parviflora extract-loaded microemulsions for skin permeation enhancement

Abstract

Keywords: Kaempferia parviflora; Microemulsion; Skin permeation

Objectives: The aim of this study was to develop the novel microemulsion (ME) systems for transdermal delivery of Kaempferia parviflora (KP) extract. The effect of ME components on the intrinsic properties and in vitro skin permeation of KP extract-loaded ME was evaluated. 

Methods: The solubility of KP in various oils (Oleic acid,caprylic/capric triglyceride, isopropyl myristate and isopropyl palmitate), surfactants (Tween 20, polyoxyethylene castor 35 oil and polyoxyethylene castor 40 oil) and co-surfactants (Propylene glycol(PG), ethoxydiglycol and butylene glycol) was studied in order to screen the suitable compositions of ME. The ME formulations composed of oil, surfactant, co-surfactant and water were selected by ME area of pseudo-ternary phase diagram. PG and ethoxydiglycol were found to be better than another investigated co-surfactant systems to construct the largest ME area of pseudo-ternary phase diagram. ME consisted of the mixture of surfactant/co-surfactant at the ratio of 1:2 was selected for incorporating KP extract. The effect of ME components on the mean droplet size, pH, conductivity and in vitro skin permeation of KP extract-loaded ME was determined.

Results: The results showed that the mixture of oil, water and the surfactant system played an important role on characteristics and in vitro skin permeation of KP extract-loaded ME. The mean droplet size of KP extract-loaded microemulsions was in the range of 20-30 nm. The pH value and conductivity of microemulsions after loading KP extract were 5.19-5.25 and 76.0-83.0 µS/cm, respectively. These results indicated that KP extract-loaded microemulsion were o/w microemulsions. The skin permeation flux of the appropriate KP extract-loaded ME formulations (oleic acid/tween 20/PG/water and oleic acid/tween 20/ethoxydiglycol/water) were significantly higher than the KP extract in water (control).

Conclusion: The results can be concluded that KP extract-loaded microemulsions were o/w microemulsions with nano-size range and enhanced skin permeation. Our finding ME system had a potential to be used for transdermal delivery of KP extract