Designing and characterization of hydrogels containing curcumin and polyhexamethylene biguanide for wound healing: In vitro pharmacological evaluation

Curcumin (CUR) is a natural compound with anti-inflammatory, and healing properties, but with high hydrophobicity and low bioavailability. Polyhexamethylene biguanide (PHMB) is a substance with antimicrobial and anti-biofilm action, but highly toxic. The development of pharmaceutical forms containing lipid nanocarriers, such as nanoemulsions (NEs), is a promising way of minimizing these challenges. This study aimed to develop and characterize NEs containing CUR and PHMB (NE-CUR-PHMB) and incorporate the developed NEs into chitosan and hydroxyethylcellulose (HEC) hydrogels aiming treatment. The study evaluated the NEs physicochemical characteristics, and possible biochemical skin changes after the proposed treatment. The effects of NEs on cell viability and antimicrobial activity were also tested. NEs were incorporated into chitosan and HEC hydrogels, and the bioadhesion and irritant potential of the formulations were evaluated. Results indicated that NE-CUR-PHMB has ∼225 nm (suitable for topical application), polydispersity index (∼0.13), positive zeta potential (∼35 mV), and drug recovery ∼75 %. The NE-CUR-PMB did not cause skin biochemical changes, increased its barrier functions, and no toxicity was observed. The formulation inhibited Pseudomonas aeruginosa growth for at least 24 h, and showed biofilm formation inhibition activity. The NEs hydrogels have greater adhesion and higher maintenance of NEs characteristics (HEC hydrogel). HET-CAM test proved the non-irritating potential of the formulations. The results show that it was possible to develop an NE containing CUR and PHMB with suitable characteristics for topical application and incorporation into hydrogels, being a promising platform for wound treatment.