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In vitro release of metformin hydrochloride from sodium alginate/polyvinyl alcohol hydrogels

Martínez-Gómez, Fabián, Guerrero, Juan, Matsuhiro, Betty, Pavez, Jorge
Carbohydrate polymers 2017 v.155 pp. 182-191
alcohols, drug carriers, encapsulation, freeze-thaw cycles, hydrocolloids, manganese, metformin, nuclear magnetic resonance spectroscopy, pH, polyvinyl alcohol, sodium alginate, temperature, ultraviolet-visible spectroscopy
Hydrogels, based on polysaccharides have found a number of applications as drug delivery carriers. In this work, hydrogels of full characterized sodium alginate (Mn 87,400g/mol) and commercial poly(vinyl alcohol) (PVA) sensitive to pH and temperature stimuli were obtained using a simple, controlled, green, low cost method based on freeze-thaw cycles. Stable hydrogels of sodium alginate/PVA with 0.5:1.5 and 1.0:1.0w/v concentrations showed very good swelling ratio values in distilled water (14 and 20g/g, respectively). Encapsulation and release of metformin hydrochloride in hydrogels of 1.0:1.0w/v sodium alginate/PVA was followed by UV spectroscopy. The hydrogel released a very low amount of metformin hydrochloride at pH 1.2; the highest release value (55%) was obtained after 6h at pH 8.0. Also, the release of metformin hydrochloride was studied by 1H NMR spectroscopy, the temporal evolution of methyl group signals of metformin showed 30% of drug release after 3h.