Preparation and Evaluation of Poloxamer/Carbopol In-Situ Gel Loaded with Quercetin: In-Vitro Drug Release and Cell Viability Study.

Background: Periodontitis is a severe chronic inflammatory disease, whose traditional systemic antimicrobial therapy faces great limitations. In-situ gels provide an effective solution as an emerging local drug delivery system.

Methods: In this study, the novel thermosensitive poloxamer/carbopol in-situ gels loaded with 20 μmol/L quercetin for the treatment of periodontitis were prepared by cold method. Thirteen batches of in-situ gels based on two independent factors (X₁: poloxamer 407 and X₂: carbopol 934P) were designed and optimized by the statistical method of central composite design (CCD). The transparency, pH, injectability, viscosity, gelation temperature, gelation time, elasticity modulus, degradation rate and in-vitro drug release studies of the batches were evaluated, and the percentage of drug release in the first hour, the time required for 90% drug release, gelation temperature, and gelation time were selected as dependent variables.

Results: These two independent factors significantly affected the four dependent variables (p < 0.05). The optimization result displayed that the optimized concentration of poloxamer 407 was 20.84% (w/v), and carbopol 934P was 0.5% (w/v). The optimized formulation showed a clear appearance (++), acceptable injectability (Pass), viscosity(151,798 mPa s), gelation temperature (36 °C), gelation time (213 s), preferable cell viability and cell proliferation, conformed to first-order release kinetics, and had a significant antibacterial effect.

Conclusions: The article demonstrates the great potential of the quercetin in-situ gel as an effective treatment for periodontitis.