A Novel Phytantriol-Based In Situ Liquid Crystal Gel for Vaginal Delivery

The purpose of this paper was to evaluate the potential of in situ liquid crystal (LC) gels based on phytantriol (PYT) for vaginal delivery. The PYT-based in situ liquid crystal gels (PILGs) were prepared by a vortex method using PYT, ethanol (ET), and water (in the ratio of 64:16:20, w/w). The internal structures of PILGs and cubic LC gels (formed by PILG phase conversion) were confirmed by crossed polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS). And the rheological tests showed that PILGs had small viscosity and excellent fluidity. The viscosities of cubic LC gels were 4~5 orders of magnitude higher than PILGs. In vitro phase conversion experiment showed that PILGs required little vaginal fluid (64.56 μL/100 mg) and time (3.92 s) to transform to LC gels. Furthermore, cubic LC gels could reside in the vaginas for more than 12 h in vivo. The in vitro release revealed that sinomenine hydrochloride (SMH) could be sustained released from the cubic gels over a period of 144 h, which was prior to SMH solution and carbomer gels. An in vivo vaginal mucosa irritation study indicated that PILGs were nonirritant and might be suitable for various vaginal applications. In conclusion, PILGs might represent a potential vaginal delivery strategy to overcome the limitations of traditional treatments.