BACKGROUND: Graft polymerization of vinylic monomers onto natural backbones is an efficient approach for the synthesis of natural-based superabsorbents. The nature of the monomers will affect the swelling behaviour of the superabsorbents. Here, a novel superabsorbent was synthesized through grafting of acrylic acid onto collagen in the presence of hydrophobic styrene as co-monomer. Subsequently, the effect of styrene on the swelling behaviour of the superabsorbent was studied. RESULTS: The highly swelling superabsorbent was prepared by introducing styrene into a collagen-graft-poly(acrylic acid)hydrogel. By inclusion of styrene monomer, the swelling capacity of the hydrogel was increased; this is discussed according to the network composition. The effect of swelling media (salt solutions and various pH values) was investigated. The results of absorbency under load showed that hydrogels containing phenyl groups exhibit better behaviour; however, by introducing styrene, the rate of water uptake and resistance to water holding under heating was reduced. Scanning electron micrographs of hydrogels revealed a decrease in porosity on using styrene. CONCLUSION: Inclusion of styrene monomer in the ionic superabsorbent caused high swelling capacity with better absorbency under load. This can be used to prepare highly swelling superabsorbents with good mechanical properties. The pH reversibility of the synthesized superabsorbent makes it a candidate for use in the controlled release of drugs and in agrochemicals.

Dihydrofolate reductase (DHFR) is an essential enzyme in the folate metabolism pathway and an important target of antineoplastic, antimicrobial, antiprotozoal, and antiinflammatory drugs. Despite the clinical effectiveness of current antifolate treatments, new drugs are needed to be designed due to developing resistance of this enzyme through multiple‐site mutagenesis. Understanding the factors affecting the ligand binding selectivity profiles among DHFR families is critical for the design of novel potent and selective inhibitors, with the least side effects, against DHFR of pathogens. Hybrid scaffolds containing pyrimidine ring are effective in DHFR inhibition. In this study, using proteochemometric (PCM) modeling, we designed and evaluated new potent pyrimidine scaffold‐based inhibitors via 3‐dimensional alignment‐free GRid‐INdependent Descriptors (GRIND), VolSurf molecular, and sequence‐based (z‐scale) descriptors to provide ligand and receptor descriptors, respectively. Validation and robustness of the model were confirmed by venetian blinds cross‐validation and Y‐scrambling approaches, respectively. Applicability domain (AD) analysis was performed to estimate the likelihood of reliable prediction for compounds. To show the applicability of the PCM model, new ligands were designed using structural data retrieved from this model. Inhibitory activities of the designs were then predicted, and selectivity ratio profiles were investigated. Finally, potent and highly selective inhibitors were identified regarding the protozoan parasite Toxoplasma gondii, followed by evaluating the ADMET parameters of the ligands.

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