A superabsorbent and pH-responsive copolymer-hydrogel based on glucomannans from Ocimum basilicum (sweet basil): A smart and non-toxic material for intelligent drug delivery.

A copolymeric hydrogel (BSM-co-MAc) was synthesized using free radical polymerization of sweet basil mucilage (BSM) and methacrylic acid (MAc). The N,N'-methylene-bis-acrylamide (MBAm) was used as a cross-linker, and potassium persulfate (KPS) as an initiator. The Fourier transform infrared (FTIR) spectroscopic analyses indicated the formation of BSM-co-MAc. Scanning electron microscopic (SEM) pictures of freeze-dried BSM-co-MAc indicated its superporous and superabsorbent nature. The studies regarding sol-gel fractions (%) in BSM-co-MAc showed that with the increase of BSM, MAc, and MBAm amount, the gel fraction improved, whereas the sol fraction lessened. The porosity (%) and swelling of BSM-co-MAc increased with the amount of BSM and decreased with the increase of MAc and MBAm. All the samples of BSM-co-MAc showed admirable swelling in phosphate buffer of pH 7.4 and nearly dead swelling in acidic buffer (pH 1.2). The swelling of BSM-co-MAc was according to 2nd-order kinetics. The vildagliptin (VG) release depended on the pH of the dissolution medium, swelling of BSM-co-MAc, and amounts of BSM, MAc, and MBAm and showed a non-Fickian diffusion. Acute oral, dermal, and eye irritation studies revealed the non-toxicity of BSM-co-MAc. Conclusively, the BSM-co-MAc is a superabsorbent, pH-responsive, biocompatible, and non-irritating biomaterial for delivering an antihyperglycemic agent.