Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis

Abstract

This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.

• Chitosan (caffeine) hydrogels
• gas chromatography
• mass spectrometry
• permeation
• sage essential oil monoterpenes

Acknowledgements

The authors would like to sincerely thank Calendula (Nová Ľubovňa, Slovak Republic) for delivering sage essential oil.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

This research was supported by the Grant FAF/12/2014 VEGA 1/0024/11, UK/138/2014, VEGA 1/0059/11, VEGA 1/0664/12 and KEGA 031UK-4/2012, and carried out in the Toxicological and Antidoping Center at the Faculty of Pharmacy, Comenius University.