A Novel Liposomal In-Situ Hydrogel Formulation of <i>Hypericum perforatum</i> L.: In Vitro Characterization and In Vivo Wound Healing Studies

<i>Hypericum perforatum</i> L. (H.P.) is a species with a well-documented history of use in wound healing practices across the globe. The objective of this study was twofold: firstly, to evaluate the in vivo efficacy of liposomal in situ gel formulations in wound healing, both clinically and histopathologically, and secondly, to determine the physicochemical characterization of liposomal in situ gel formulations. The in vitro studies will be assessed in terms of particle size, zeta potential, release kinetics, rheological behaviors, and antioxidant and antimicrobial properties. The in vivo studies will be evaluated in clinical animal experiments and pathology studies. The in-situ hydrogel formulations were prepared using the physical cross-linking method with Poloxamer 188, Poloxamer 407, Ultrez 21, and Ultrez 30. The liposome formulations phospholipid 90H and lipoid S100 were prepared using the thin film solvent evaporation method. The antioxidant activity of the samples was evaluated through in vitro studies employing the DPPH antioxidant activity, ABTS+ test, and FRAP test. The antimicrobial activity of the samples was evaluated through the determination of MIC and MBC values employing the 96-well plate method. In vivo, 36 male New Zealand rabbits aged 32–36 weeks were utilized, with six rabbits in each group. The groups were composed of six distinct groups, including conventional and in situ gel liposome formulations of HHPM, three different commercial preparations, and a control group (<i>n</i> = 6). The HHPM-LG8 formulation developed in this study was found to be applicable in terms of all its properties. The new liposomal in situ hydrogel formulation demonstrated notable wound healing activity, a result that was supported by the formulation itself.