Background: In topical wound treatment, the combination of anti-infectious therapy and a healing-promoting moisturization has not been accomplished yet. Objective: Evaluation of a new topical drug consisting of a povidone-iodine (PVP-I) liposome hydrogel allowing for both antiseptic and moist treatment. Methods: Pharmaceutical formulation of a complex of PVP-I (3%) and phosphatidylcholine in a hydrogel. In vitro, interaction of the complex with relevant micro-organisms was analysed by electron microscopy. Antimicrobial activity was investigated using Staphylococcus aureus in a suspension test. Tissue toxicity was examined by an explantation test in a rodent model. A randomized clinical study on efficacy and tolerability in wound healing was carried out on 35 patients with mesh grafts in parallel groups (PVP-I liposome hydrogel vs. Bactigras) for proof of concept in humans. Results: A direct interaction of the PVP-I liposomes with micro-organisms by attachment to the cell surface was documented. A significantly better microbicidal activity and tissue tolerability of the PVP-I liposome hydrogel compared to conventional PVP-I formulations was shown. The results of the clinical study, especially measurements of neo-epithelization per time and transplant loss, demonstrate significant differences in favour of the PVP-I liposome hydrogel. Conclusion: The novel PVP-I liposome hydrogel combines microbicidal and wound healing activities resulting in enhanced epithelization.

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Moist treatment of wounds has been shown to improve epithelialization, however at an increased risk of bacterial infection. In this monocentric, randomized, open, phase II pilot study of polyvinyl pyrrolidone-iodine, a well-established topical antiseptic was tested in a new liposomal complexed form in patients receiving meshed skin grafts after burns or reconstructive procedures. Mesh skin graft sites of 36 patients were dressed either with the new polyvinyl-pyrrolidone-iodine liposome hydrogel formulation (Betasom hydrogel) (n = 21), or chlorhexidine-gauze (n = 15). After the first dressing change, wounds were assessed daily and documented every other day until they were healed. Methods of analysis included clinical assessment, photoplanimetry (rate of epithelialization), impedance measurement (moisture of surface and wound healing quality), patient's assessment of pain and other sensations, and thyroid hormones (T3, T4, and TSH). The rate of epithelialization was improved with Betasom hydrogel compared to chlorhexidine-gauze on day 11 (96.3% vs. 75.9% p = 0.056) and significantly on day 13 (100% vs. 82.3% p = 0.005), respectively. Impedance measurements showed an earlier return to normal values (day 9) in Betasom-hydrogel-treated wounds as opposed to chlorhexidine treatment (day 11). Clinical assessment indicated significantly better antiseptic efficacy (p = 0.002) and wound healing quality (p = 0.004) of Betasom hydrogel. Graft loss occurred at a significantly lower rate in Betasom treatment (n = 1; 5%), than in chlorhexidine treatment (n = 5; 35.7%) (p = 0.001). No relevant adverse events or clinically relevant changes of thyroid hormones were observed with Betasom hydrogel. The rationale of this new polyvinyl pyrrolidone-iodine liposomal formulation was based on the properties of liposomes that provide higher moisture to the wound surface, release PVP-iodine at a low rate, and target the substance more exactly by interaction with the cell surface. These initial clinical results show earlier epithelialization and better healing in wounds treated with polyvinyl pyrrolidone-iodine liposome hydrogel, which combines moisture and antisepsis, compared to wounds treated with a conventional antiseptic chlorhexidine-gauze.