Formulation and evaluation of thermoresponsive polymeric blend as a vaginal controlled delivery system

Abstract

Thermoresponsive polymers have the ability to undergo rapid changes in response to subtle environmental conditions and make stimuli-responsive materials attractive. They are candidates for minimally invasive, targeted and personalized drug delivery applications. Curcumin (CUR) is a phytochemical compound characterized by its low intrinsic toxicity and a wide variety of therapeutic effects. The modulating of the viscoelastic properties and bioadhesive characteristics of the thermoresponsive hydrogel (poloxamer 407) was achieved using a ternary system formed with chitosan and hydroxypropylmethylcellulose K4M (M20). The curcumin in solid dispersion form (CUR-SD) was used in the hydrogel preparation. The physical–chemical, physiomechanical, oxidative stress properties and antioxidant activity were evaluated and compared. Curcumin in SD form is more soluble and stable than in the physical mixture (PM) or free form. The transition from liquid to gel (Tsol–gel) temperature of the M20-SD formulation occurred at 36 °C. The CUR delivery profiles followed the Hixson–Crowell’s model. The M20-SD formulation showed antioxidant activity and as a strong inhibitor of oxidative stress. Analysis of results suggests that CUR-SD thermoresponsive hydrogel can be used via to the vaginal route for the treatment of mucosal inflammation and infectious disease, including HPV. The elastomeric hydrogel is formed by covalently cross-linked long and flexible polymer chains aggregated with water. The analysis results showed that M20-SD could remain at the application site for a sufficient time to permit the controlled delivery and to improve the therapeutic activity of CUR.