Synthesis and In Vitro Evaluation of Aspartic Acid Based Microgels for Sustained Drug Delivery

The main focus of the current study was to sustain the releasing behavior of theophylline by fabricated polymeric microgels. The free radical polymerization technique was used for the development of aspartic acid-co-poly(2-acrylamido-2-methylpropanesulfonic acid) microgels while using various combinations of aspartic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N′,N′-methylene bisacrylamide as a polymer, monomer, and cross-linker, respectively. Ammonium peroxodisulfate and sodium hydrogen sulfite were used as initiators. Characterizations such as DSC, TGA, SEM, FTIR, and PXRD were performed for the fabricated microgels to assess their thermal stability with unreacted polymer and monomer, their surface morphology, the formation of a new polymeric system of microgels by evaluating the cross-linking of functional groups of the microgels’ contents, and to analyze the reduction in crystallinity of the theophylline by fabricated microgels. Various studies such as dynamic swelling, drug loading, sol–gel analysis, in vitro drug release studies, and kinetic modeling were carried out for the developed microgels. Both dynamic swelling and percent drug release were found higher at pH 7.4 as compared to pH 1.2 due to the deprotonation of functional groups of aspartic acid and AMPS. Similarly, sol–gel analysis was performed and an increase in gel fraction was observed with the increasing concentration of microgel contents, while sol fraction was decreased. Conclusively, the prepared carrier system has the potential to sustain the release of the theophylline for an extended period of time.

Preparation, Characterization, Swelling Potential and In-Vitro Evaluation of Sodium Poly(Styrene Sulfonate)-Based Hydrogels for Controlled Delivery of Ketorolac Tromethamine

The objective of the current study work was to fabricate sodium poly(styrene sulfonate-co-poly acrylic acid) (SPSPAA) hydrogels by using a free radical co-polymerization method for controlled delivery of ketorolac tromethamine (KT). Polymer (sodium poly(styrene sulfonate) (SPS) polymerized with monomer acrylic acid (AA) in the presence of initiator ammonium peroxodisulfate (APS) and cross-linker N′,N′-Methylene bisacrylamide (MBA). Different combinations of polymer, cross-linker and monomer, were employed for development of polymeric hydrogels. Various studies such as sol-gel, drug loading, dynamic swelling, and drug release studies were carried out to know the sol and gel portion of SPSPAA, swelling behavior of hydrogels at different pH media (1.2 and 7.4), quantification of drug loaded by fabricated hydrogels, and amount release of KT at pH 1.2 and 7.4. Higher dynamic swelling was found at pH 7.4 compared to pH 1.2, and as a result, greater percent release of drug was perceived at pH 7.4. Thermal stability, crystallinity, confirmation of functional groups and development of a new polymeric system, and surface morphology were evaluated via Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) respectively. The results showed that the present work could be used as a potential candidate for controlled delivery of KT.

DESCRIPTION OF CHITOSANE GRAFTED ACRYLIC ACID BASED HYDROGEL SWELLING KINETICS AND THEIR USE IN NEW DESIGNED SYSTEM

Chitosan based hydrogel was synthesized via free-radical polymerization in a two-step procedure, after modification of chitosan by acrylic acid. Dynamic swelling test was carried out in distilled water at room temperature. Swelling kinetics was modeling using the principle of assuming the equation for a swelling ratio-time empirical dependence. Using regression analysis in this way gives the possibility for simpler determination of swelling ratio-time empirical dependence, knowing the graph functions. Obtained hydrogel was used for preparation of new bilayer hydrogel system which has potential application in wound dressing systems and other fields where pH sensitivity and improved mechanical properties of biopolymers are required in framework of green, cost-effective process.

Gel rupture during dynamic swelling

A complex, three-stage fracture process is described for hydrogels, resulting in material failure. This process is markedly different than that observed in brittle materials, and we describe how this process varies with network architecture.

A pH-sensitive, stimuli-responsive, superabsorbent, smart hydrogel from psyllium (Plantago ovata) for intelligent drug delivery

Herein, we report the dynamic swelling, stimuli responsive swelling-deswelling properties, sub-acute toxicity studies and sustained drug release potential of a polysaccharide-based hydrogel isolated from psyllium husk (a well-known dietary fiber).