Hydrogel Films Based on Chitosan and Oxidized Carboxymethylcellulose Optimized for the Controlled Release of Curcumin with Applications in Treating Dermatological Conditions.

Cross-linked chitosan (CS) films with aldehyde groups obtained by oxidation of carboxymethyl cellulose (CMC) with NaIO4 were prepared using different molar ratios between the CHO groups from oxidized carboxymethyl cellulose (CMCOx) and NH2 groups from CS (from 0.25:1 to 2:1). Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy demonstrated the aldehyde groups' presence in the CMCOx. The maximum oxidation degree was 22.9%. In the hydrogel, the amino groups' conversion index value increased when the -CHO/-NH2 molar ratio, cross-linking temperature, and time increased, while the swelling degree values decreased. The hydrogel films were characterized by scanning electron microscopy (SEM) and FTIR analysis. The curcumin encapsulation efficiency decreases from 56.74% to 16.88% when the cross-linking degree increases. The immobilized curcumin release efficiency (REf%) and skin membrane permeability were evaluated in vitro in two different pH solutions using a Franz diffusion cell, and it was found to decrease when the molar ratio -CH=O/NH2 increases. The curcumin REf% in the receptor compartment was higher at pH = 7.4 (18%- for the sample with a molar ratio of 0.25:1) than at pH = 5.5 (16.5%). The curcumin absorption in the skin membrane at pH = 5.5 (47%) was more intense than at pH = 7.4 (8.6%). The curcumin-loaded films' antioxidant activity was improved due to the CS presence.

The protective effect of Hibiscus sabdariffa calyxes extract against cypermethrin induced oxidative stress in mice.

Cypermethrin (Cyp) is a kind of pyrethroids compound that is broadly used against different species of insects and pests. Cyp can also elicit a range of neurotoxic, immunotoxic, genotoxic and reproductive toxic effects on various experimental organisms. The aim of this study was to evaluate the protective effects of Hibiscus sabdariffa against the toxicity damage induced by Cyp exposure. The Hibiscus sabdariffa calyxes extract was given to mice (200-500 mg/kg bw). The mice, which were treated with Cyp and Hibiscus sabdariffa, were divided into six groups of six mice each. Groups I, IV and VI were used as control and groups II CYP control (20 mg/kg body weight)., groups III and V were treated with Hibiscus sabdariffa extract (200 and 500 mg/kg body weight) plus (20 mg/kg body weight) for 21 days Furthermore, HPLC was used to identify the compound fraction. This result showed Cyp -induced biochemical changes in all organs of mice. Cyp caused decreased CAT activity, inhibition of AChE activity and increased the levels of H2O2 and MDA in brain, heart, liver and kidney. Hibiscus sabdariffa exhibited antioxidant effect and significantly attenuated the neurotoxicity of Cyp. Hibiscus sabdariffa exhibits neuroprotective effects and can be an effective and novel alternative approach to reduce the risk caused by pyrethroid compound.