This study investigated the use of pure polymer chitosan (CS), xanthan gum (XG), monomer 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and initiator potassium persulfate (KPS) as drug carrier system crosslinked through N ′ N ′ -methylene bis-acrylamide (MBA) for controlled drug delivery of acyclovir (ACV). ACV is highly effective and selective antiviral drugs used for prophylaxis and treatment against herpes simplex viruses (HSV) infections. Present oral marketed formulations are associated with number of side effects and shortcomings which hampered its clinical effectiveness. Hydrogels (FCX1-FCX9) composed of CS, XG, AMPS, MBA, and KPS were prepared by free radical polymerization technique and characterized through FTIR, PXRD, thermal analysis and SEM. Swelling dynamics and drug release behavior was also investigated. FTIR studies confirmed that ACV was successfully encapsulated into hydrogel polymeric network. SEM revealed porous structure whereas thermal analysis showed enhanced thermal stability of polymeric network. PXRD indicated amorphous dispersion of ACV during preparation process. Swelling dynamics and ACV release behavior from developed hydrogels was dependent on pH of the medium and concentration of pure reactants used. Korsmeyer-Peppas model was best fit to regression coefficient. The present work demonstrated a potential for developing a pH sensitive hydrogel for an antiviral drug ACV by using pure polymers CS, XG, and monomer AMPS.

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An oral route of administration is a most acceptable route for a patient, so we designed chemically cross-linked polyethylene glycol-co-poly(methacrylic acid) oral hydrogels (PEGMA 4000) by free radical polymerization method for pH-responsive colon target delivery of oxaliplatin (OXP). Polyethylene glycol (PEG 4000) was crosslinked chemically with methacrylic acid (MAA) in distilled water. Ammonium peroxodisulfate (APS) and N, N-methylene bisacrylamide (MBA) were used as initiator and cross-linker respectively. OXP was loaded in prepared hydrogels. FTIR, DSC, TGA, SEM, and XRD were conducted for characterization of developed hydrogels which endorsed the formation of new polymeric network. The pH-sensitive behavior of hydrogels was observed by swelling dynamics and equilibrium swelling ratio at low (1.2) and higher pH (7.4). Toxicity study was also conducted on rabbits to evaluate toxicity and biocompatibility of developed carrier system to biological system. Hydrogels with higher PEG 4000 concentration showed maximum swelling and higher drug loading at 7.4 pH. Toxicity study confirmed the developed hydrogels as non-toxic and biocompatible for biological system. Resultantly, these hydrogels can become an excellent candidates for colon targeting of OXP to treat colorectal cancer with no toxicity.

A series of sodium alginate-graft-poly(acrylic acid) hydrogels (SA-g-pAA hydrogels) were synthesized with sodium alginate (SA) and acrylic acid (AA) in aqueous solution, ethylene glycol dimethacrylate (EGDMA) as a cross-linker and ammonium peroxodisulfate (APS) as an initiator. Hydrogels were evaluated for thermal stability (TGA & DSC), revealing their higher strength toward thermal variation as compared to individual components. SEM micrographs show smooth and solid outer surface with a lack of porosity on it. FTIR results revealed the grafting reaction of AA on SA. Hydrogels were then evaluated for pH responsive behavior by equilibrium swelling ratio and swelling dynamics at low and high pH. Furthermore, these cross-linked networks were also tested for the release of Loxoprofen sodium hydrate (LSH). Drug was loaded by diffusion method and showed pH-dependent drug release characteristics. Korsmeyer-Peppas model is the best fit model to explain drug release from the cross-linked network. Maximum swelling, drug loading, and release has been observed at pH 7.4. It is concluded that highly stable SA and AA based polymeric matrixes are developed. These polymeric matrixes have potential to be used as a carrier for controlled delivery of LSH.

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