Poly(vinylpyrrolidone)-Chitosan Hydrogels as Matrices for Controlled Drug Release

Abstract

In this study, hydrogels based on poly(vinylpyrrolidone) and chitosan, derived from different mixing ratios of poly(vinylpyrrolidone)/chitosan, were synthesized by the freeze-drying technique with the aim of obtaining new systems that could be used to release tetracycline hydrochloride (TH). Freeze-drying methods were also used to prepare the hydrogels containing TH. The hydrogels were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy, as well as in terms of dynamic water vapour sorption capacity. The poly(vinylpyrrolidone)/chitosan hydrogels were evaluated with regard to the release of TH. The release profiles of TH from the poly(vinylpyrrolidone)/chitosan hydrogels depended on the chitosan content. It could be seen that if the concentration of chitosan was too high, the release was delayed and not fully achieved, because the release of the drug was prevented by the crystalline areas of the chitosan. According to the release study, the drug release mechanism of the poly(vinylpyrrolidone)/chitosan hydrogels loaded with TH perfectly fitted the Higuchi and the Korsmeyer-Peppas models. The highest value of water vapor sorption capacity was obtained for the hydrogel with the poly(vinylpyrrolidone)/chitosan ratio of 50/50. PVP-CS loaded with 3 wt% TH may potentially be used for the controlled delivery of tetracycline to treat oral infections.

Self-Healing Chitosan Hydrogels: Preparation and Rheological Characterization

“…Nevertheless, gravimetric monitoring revealed a progressive degradation, reaching a mass loss from 13 to 56%, function of media pH and hydrogel composition (Figure 4). As expected, the hydrogels degraded faster in acidic acetate buffer (pH = 5.6), in agreement with the shifting of imination equilibrium to the reagents and faster dissolution of chitosan under the influence of protons [41,42]. Interestingly, against the expectations, the mass loss decreased as the content of P5P decreased.…”

Chitosan-Based Therapeutic Systems for Superficial Candidiasis Treatment. Synergetic Activity of Nystatin and Propolis

“…Based on the IUPAC classification the isotherms are related to Type V curves, specific to water sorption on hydrophobic micro-and mesoporous surfaces and indicate weak adsorbent-water interaction [27]. Similar isotherms were registered for other chitosan-based hydrogels [60,61].…”