Georgian bentonite clay-polymer system as carrier for volatile oil in topical applications

Abstract

This study focuses on developing a polymer–clay hybrid system using Georgian bentonite clay (Tikha–Ascane, TA) and Carbopol (CA) as a carrier for essential oil (EO) derived from Matricaria chamomilla L. cultivated in East Georgia. EO was extracted via hydrodistillation and characterized using GC-MS and FTIR techniques. The CA–TA and CA–TA–EO formulations were evaluated for key physicochemical parameters including pH, viscosity, rheology, spreadability, compatibility, moisture loss, uniformity, and stability. The EO yield was 0.3% from air-dried plant material. The main components were bisabolol oxide A (38.2%), α-bisabolol oxide B (12.91%), (cis)-β-farnesene (11.8%), α-bisabolol (8.83%), spathulenol (2.27%), chamazulene (1.99%), cis-ene-yne-dicycloether (6.51%), and β-copaene (0.38%). These results suggest that the local chamomile chemotype is rich in bisabolol oxide A. The optimized hydrogel formulation was homogeneous, stable, and demonstrated favorable rheological properties, suitable for topical application. Chromatographic analysis confirmed the successful incorporation of EO into the gel, which achieved an encapsulation efficiency of 58.34%. Overall, the study confirms the compatibility of Georgian bentonite clay with CA polymer, forming an effective matrix for volatile oil delivery in semisolid dosage forms.