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A variety of pH responsive hydrogels possessing macroporous interiors resembling honey-comb framework with continuous skin on the surface have been developed by free radical aqueous copolymerization of Acrylic acid (AAc) and 2-(Dimethylamino)ethyl methacrylate (DMAEMA) (Poly (AAc-co-DMAEMA) (PAD) hydrogels).This one step polymerization process makes scaling-up easier for mass production. Our formulations, being devoid of any chemical cross-linkers, remained dimensionally stable in buffer solutions of pH 1.2-7.4 with interlocked nanogels being identified as the building blocks of the network structures. Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), uniaxial compression testing and scanning electron microscopy (SEM) were used to characterize the hydrogels (PADs). Compressive elastic modulus and compressive strength of the swollen hydrogels at pH 7 were found to vary with composition from ~3 to ~11 kPa and ~178 to ~206 kPa, respectively. The swollen gels showed fairly strong viscoelastic behaviour and underwent deformation from ~70% to 85% before failure, indicating the formation of robust 3D structures of PADs. Preliminary investigation into the biocompatibility of our hydrogels done by cytotoxicity assays using HeLa and McCoy mouse fibroblast cell lines have revealed that they are non-cytotoxic, paving the way for further biomedical applications. Swelling behaviour and release kinetics of bovine serum albumin (BSA) were investigated in various buffer solutions that mimic the pH-metric hierarchy in gastrointestinal (GI) tract. Equilibrium swelling ratio was found to vary from 171% (mass) to 2027% (mass) depending on the pH and composition of hydrogels. Different compositions of PAD systems were investigated to verify the possibility of tailor-making the drug release behaviour of PAD formations.

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A novel approach to synthesize anti-metabolite conjugated and intense blue fluorescence emitting smart polymeric nanoparticles is reported for the efficient delivery anticancer drug and self-monitoring its effect in the drug-resistant...

The structure of naturally occurring anhydrovitamin A2 was elucidated as 3-hydroxyanhydroretinol from study of its u.v.--visible, i.r., n.m.r. and mass spectra. The structure has been confirmed by a chemical synthesis. Saccobranchus fossils, a freshwater fish, can convert 3-hydroxyretinol into 3-hydroxyanhydroretinol, which in turn is converted into-3-dehydroretinol. Chemical conversion of 3-hydroxyretinol into 3-dehydroretinol was also carried out.

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The transition metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) with bidentate Schiff base ligands (HL1−5) were obtained from condensation of 1, 2, 3, 4‐tetrahydro‐naphthalen‐1‐ylamine with methanolic solution of 3‐hydroxy‐salicylaldehyde, 4‐hydroxy‐salicylaldehyde, 5‐bromo‐salicylaldehyde, 3,5‐dibromo‐salicylaldehyde, and 2‐hydroxy‐1‐napthaldehyde. The synthesized compounds were structurally elucidated by spectral and physical methods. The spectral characterization emphasized bidentate nature (NO) of Schiff base ligands which gets chelated with metal via nitrogen atom of imine group and deprotonated oxygen of salicylaldehyde/2‐hydroxy‐1‐napthaldehyde group to form octahedral geometry around metal atom. Thermal results supported that the complexes are stable upto 200°C leaving metal oxide as an end products. The reported compounds (1–25) in this series were screened against the bacterial strains, that is, two Gram positive: Bacillus subtilis and Staphylococcus aureus, two Gram negative: Pseudomonas aeruginosa and Escherichia coli, and two fungal strains: Candida albicans and Aspergillus niger and their results that indicated moderate to good activity with compounds 20 and 21 having good antimicrobial activity (minimum inhibitory concentration [MIC] value 0.0269–0.0067 μmol/ml) as compared with control drugs ciprofloxacine and fluconazole. Furthermore, cytotoxic studies of synthesized compounds were carried out against three human cancer cell lines: HCT‐116 (colon), A549 (alveolar), and MCF‐7 (breast) using standard drug paclitaxel. The results demonstrated that compounds 1 (IC50 values = 12.93, 15.13, 17.24), 3 (11.9, 9.29, 12.64), 9 (17.06, 20.06, 22.87), 14 (16.21, 18.47, 20.00), and 25 (17.54, 17.21, 20.23) for three cancer cell lines were found to be most potent candidates among the synthesized compounds.