In current research study, novel chitosan-based hydrogel was formulated via crosslinking graft copolymerization of acrylic acid (AA) and chitosan. Potassium persulfate was used as free radical generator in the presence of crosslinker (methylene bis acrylamide (MBA)). FTIR spectroscopy was employed to elucidate structure of hydrogel. Moreover, sample morphology was examined by scanning electron microscopy (SEM) and thermal analysis was conducted by using thermogravimetric analysis (DSC/TGA). The influence of reaction variables such as concentration of chitosan (CS), acrylic acid (AA) and MBA was optimized to attain hydrogel with significant swelling capacity. Chitosan-g-AA hydrogel depicted pH responsive attributes and swelling–deswelling pulsatile behavior was recorded at pHs 1.2 and 7.4. This on–off switching makes hydrogel ideal candidate for controlled drug delivery. Graphical Abstract

Tofacitinib is an antirheumatic drug characterized by a short half-life and poor permeability, which necessitates the development of sustained release formulation with enhanced permeability potential. To achieve this goal, the free radical polymerization technique was employed to develop mucin/chitosan copolymer methacrylic acid (MU-CHI-Co-Poly (MAA))-based hydrogel microparticles. The developed hydrogel microparticles were characterized for EDX, FTIR, DSC, TGA, X-ray diffraction, SEM, drug loading; equilibrium swelling (%), in vitro drug release, sol–gel (%) studies, size and zeta potential, permeation, anti-arthritic activities, and acute oral toxicity studies. FTIR studies revealed the incorporation of the ingredients into the polymeric network, while EDX studies depicted the successful loading of tofacitinib into the network. The thermal analysis confirmed the heat stability of the system. SEM analysis displayed the porous structure of the hydrogels. Gel fraction showed an increasing tendency (74–98%) upon increasing the concentrations of the formulation ingredients. Formulations coated with Eudragit (2% w/w) and sodium lauryl sulfate (1% w/v) showed increased permeability. The formulations equilibrium swelling (%) increased (78–93%) at pH 7.4. Maximum drug loading and release (%) of (55.62–80.52%) and (78.02–90.56%), respectively, were noticed at pH 7.4, where the developed microparticles followed zero-order kinetics with case II transport. Anti-inflammatory studies revealed a significant dose-dependent decrease in paw edema in the rats. Oral toxicity studies confirmed the biocompatibility and non-toxicity of the formulated network. Thus, the developed pH-responsive hydrogel microparticles seem to have the potential to enhance permeability and control the delivery of tofacitinib for the management of rheumatoid arthritis.

Current exploration unveils the promising role of arabinoxylan (AX) in targeted delivery of acid labile active moiety, by using methacrylic acid (MAA) as monomer, N′,N′-methylene-bis-acrylamide (MBA) as crosslinker and ammonium persulfate as initiator. Different feed composition of AX, MAA and MBA was blended to optimize hydrogels by free radical polymerization technique. Formulation AXMA2 showed maximum swelling and drug release at pH 7.4. Fourier transform infrared spectroscopy (FTIR) depicts crosslinking of MAA and AX based. Thermal characterization confirmed the formation of thermodynamically stable hybrid. However, morphological studies showed porous architecture. The pH sensitivity of hydrogels has been affirmed by swelling dynamics, equilibrium swelling ratio (ESR), on–off switching and drug release studies in acidic and alkaline pH. Drug release studies showed controlled release of the perindopril erbumine from polymeric network. Crosslinked AX nexus can be used as promising carrier for the configuring and formulating targeted drug-delivery systems.

Oral delivery of insulin has always been a challenging task due to harsh gut environment involving variable pH and peptidase actions. Currently, no Food and Drug Administration (FDA) approved oral insulin formulation is commercially available, only intravenous (IV) or subcutaneous (SC) routes. Therefore, it is really cumbersome for diabetic patients to go through invasive approaches for insulin delivery on daily basis. In the present study, a novel pH-responsive hydrogel nanocomposite (NC) system was developed and optimized for safe oral delivery of insulin. Black seed polysaccharide extract-based hydrogel (BA hydrogel) was formulated by free radical polymerization and loaded with insulin. Blank BA hydrogel was also incorporated with insulin-loaded montmorillonite nanoclay (Ins-Mmt) to form an Ins-Mmt-BA hydrogel NC and compared with the insulin-loaded hydrogel. Swelling, sol-gel analysis and in vitro release studies proved that Ins-Mmt-BA6 hydrogel NC has the best formulation, with 96.17% maximum insulin released in 24 h. Kinetic modeling applied on insulin release data showed the Korsemeyer-Peppas model (R² = 0.9637) as the best fit model with a super case II transport mechanism for insulin transport (n > 0.89). Energy Dispersive X-ray (EDX) Spectroscopy, Fourier Transformed Infrared (FTIR) spectroscopy and Powdered X-ray diffraction (PXRD) analysis results also confirmed successful development of a hydrogel NC with no significant denaturation of insulin. Toxicity results confirmed the safety profile and biocompatibility of the developed NC. In vivo studies showed a maximum decrease in blood glucose levels of 52.61% and percentage relative bioavailability (% RBA) of 26.3% for an Ins-Mmt-BA hydrogel NC as compared to BA hydrogels and insulin administered through the SC route.