A Smart Hydrogel from Salvia spinosa Seeds: pH Responsiveness, On-off Switching, Sustained Drug Release, and Transit Detection

Stimuli-responsive glucuronoxylan polysaccharide from quince seeds for biomedical, food packaging, and environmental applications

Mucilage is a gelatinous mixture of polysaccharides secreted from the seed coat and/or pericarp of many plant seeds when soaked in water. Mucilage affected seed germination while maintaining hydration levels during scarcity. Cydonia oblonga (quince) seeds are natural hydrocolloids extruding biocompatible mucilage mainly composed of polysaccharides. Quince seed mucilage (QSM) has fascinated researchers due to its applications in the food and pharmaceutical industries. On a commercial scale, QSM preserved the sensory and physiochemical properties of various products such as yogurt, desserts, cakes, and burgers. QSM is responsive to salts, pH, and solvents and is mainly investigated as edible coatings in the food industry. In tablet formulations, modified and unmodified QSM as a binder sustained the release of various drugs such as cefixime, capecitabine, diclofenac sodium, theophylline, levosulpiride, diphenhydramine, metoprolol tartrate, and acyclovir sodium. QSM acted as a reducing and capping agent to prepare nanoparticles for good antimicrobial resistance, photocatalytic characteristics, and wound-healing potential. The present review discussed the extraction optimization, chemical composition, stimuli-responsiveness, and viscoelastic properties of mucilage. The potential of mucilage in edible films, tissue engineering, and water purification will also be discussed.

Citric acid cross-linking of a hydrogel from Aloe vera (Aloe barbadensis M.) engenders a pH-responsive, superporous, and smart material for drug delivery

The current research work is based on the evaluation of a citric acid (CA) cross-linked Aloe vera (Aloe barbadensis M.) leaf hydrogel (CL-ALH) for pH-dependent and sustained drug release application. The CA was used in different concentrations (1.25, 2.5, 5.0, and 10.0%) to cross-link the ALH using homogenous reaction conditions. The synthesis of CL-ALH was confirmed through Fourier transform and nuclear magnetic resonance spectroscopic studies. The thermal analysis indicated that the ALH and CL-ALH were stable and decomposed in two steps. The scanning electron microscopic images of CL-ALH confirmed its porous nature due to the presence of interconnected channeling. The swelling of CL-ALH was evaluated at pH 1.2, 6.8, and 7.4 as well as in deionized water (DW). High swelling of CL-ALH was observed in DW, and at pH 7.4 and 6.8 whereas, less swelling of CL-ALH was witnessed at pH 1.2. CL-ALH also exhibited swelling/deswelling behavior in DW and ethanol, DW and normal saline, and at pH 7.4 and 1.2. Tablets were prepared from CL-ALH as a release retarding agent demonstrating the sustained release of venlafaxine hydrochloride (VFX) for 8 h. Whereas, VFX was released within 4 h from the ALH-based tablet formulation (un-cross-linked material) indicating the prolonged and sustained release behavior of CL-ALH. The VFX was released from CL-ALH tablets and followed zero-order kinetics. The mechanism followed by VFX release from CL-ALH tablets was non-Fickian diffusion. The in vivo fate of the tablet formulation was observed through an X-ray study. The CL-ALH-based tablet safely passed through the stomach of a stray dog without any significant erosion and then disintegrated in the small intestine and colon. These findings confirmed that the CL-ALH is an effective excipient for designing a sustained-release drug delivery system for the small intestine and colon.

Fabrication and optimization of febuxostat-loaded chitosan nanocarriers for better pharmacokinetics profile

The current research was planned to enhance the bioavailability of hydrophobic drug after oral administration through the development of a nanoparticle drug delivery system (DDS). Therefore, febuxostat-loaded chitosan nanoparticles (FLC NPs) were prepared using a modified ionic gelation method and optimized the reaction conditions through the design of experiments. Design expert software was used to check the desirability of the central composite design and the interactive effects of the independent variables (chitosan concentration, ratio of chitosan to linker, and pH of the medium) on the response variables (size distribution, zeta potential, polydispersity index (PDI), and entrapment efficiency (EE)) of FLC NPs. All ingredients of the optimized formulation (formulation Q) were compatible with each other as evident from FTIR, PXRD, and TGA studies, and displayed 234.7 nm particle size, 0.158 PDI, 25.8 mV zeta potential, and 76.9 % EE. TEM, SEM, and AFM exhibited a smooth, dense, and uniform structure without any visible pores in the structure of FLC NPs. The in vitro and in vivo drug release studies described a sustained release pattern of febuxostat and increased relative bioavailability by 286.63 %. Considering these findings, this chitosan nanoparticle DDS can further be used for improving the EE and bioavailability of hydrophobic drugs.

Polysaccharide-Based Hydrogel from Seeds of Artemisia vulgaris: Extraction Optimization by Box-Behnken Design, pH-Responsiveness, and Sustained Drug Release

The current research work focuses on the extraction and optimization of the hydrogel (AVM) from the seeds of Artemisia vulgaris using Box-Behnken design-response surface methodology (BBD-RSM). The AVM was obtained through a hot water extraction process. The influence of different factors, including pH (U = 4 to 10), temperature (V = 25 to 110 °C), seed/water ratio, i.e., S/W ratio (W = 1/10 to 1/70 w/v), and seed/water contact time, i.e., S/W time (X = 1 to 12 h) on the yield of AVM was evaluated. The p-value for the analysis of variance (ANOVA) was found to be <0.001, indicating that the yield of AVM mainly depended on the abovementioned factors. The highest yield of AVM, i.e., 15.86%, was found at a pH of 7.12, temperature of 80.04 °C, S/W ratio of 1/33.24 w/v, and S/W time of 8.73 h according to Design-Expert Software. The study of the pH-responsive behavior of AVM in tablet form (formulation AVT3) revealed that AVM is a pH-responsive material with significantly high swelling at pH 7.4. However, less swelling was witnessed at pH 1.2. Moreover, AVM was found to be a sustained release material for esomeprazole at pH 7.4 for 12 h. The drug release from AVT3 was according to the super case-II transport mechanism and zero-order kinetics.

Polymer Gels: Classification and Recent Developments in Biomedical Applications

Polymer gels are a valuable class of polymeric materials that have recently attracted significant interest due to the exceptional properties such as versatility, soft-structure, flexibility and stimuli-responsive, biodegradability, and biocompatibility. Based on their properties, polymer gels can be used in a wide range of applications: food industry, agriculture, biomedical, and biosensors. The utilization of polymer gels in different medical and industrial applications requires a better understanding of the formation process, the factors which affect the gel's stability, and the structure-rheological properties relationship. The present review aims to give an overview of the polymer gels, the classification of polymer gels' materials to highlight their important features, and the recent development in biomedical applications. Several perspectives on future advancement of polymer hydrogel are offered.