Synthesis and characterization of poly(HEMA‐MAA) hydrogel carrier for oral delivery of insulin

Abstract

Poly(HEMA-MAA) hydrogel particles were synthesized by redox free-radical polymerization using 2-hydroxyethylmethacrylate, different concentration of methacrylic acid as monomer, ethyleneglycol dimethacrylate as crosslinking agent, and APS/TEMED as free-radical initiator. Fourier transform infrared spectrum of poly(HEMA-MAA) hydrogels showed intense absorption peak of carbonyl group at $ 1700 cm À1 due to carboxylic acid groups of MAA, peak at $ 2960 cm À1 due to CH stretching and vinylic peak at 1700 cm À1 independent of MAA concentration. Highest swelling percentage 587% was observed in case of poly(HEMA-MAA) hydrogel synthesized using 30% of MAA while lowest swelling percentage 413% was observed in hydrogel synthesized 10% of MAA at basic pH (8.0). Scanning electron micrograph of copolymeric particles showed the irregular shape of poly(HEMA-MAA) particles with conglomeration with each due to ionization of carboxylic groups. Insulin was radiolabeled using technetium-99m radionuclide and the radiolabeling efficiency was found to be 99%. Poly(HEMA-MAA) hydrogel having 60% of MAA showed the highest insulin loading efficiency of 68% while lowest 37% was observed in case of 10% MAA hydrogel. Insulin release studies showed only 35-65% of insulin was released into the medium from particles at pH 2.5 in 60 min, while insulin release was significantly higher at pH 7.4. Hypoglycemic effect of the 60 and 80 I.U./kg insulin dose loaded in poly(HEMA-MAA) copolymeric particles were carried out in fasted diabetic rats and highest decrease in blood glucose level from 506 mg/dL to 170 mg/dL was observed within first 3 h.

Influence of N‐vinyl‐2‐pyrrolidone and methacrylic acid on thermal curing process of 2‐hydroxyethyl methacrylate hydrogel

“…According to the previous literature, PHEMA lenses did not have ionizable carboxylic acid groups, while P(HEMA/MA) lenses had stronger interactions with water molecules, yielding higher bulk water contents because the carboxylic acid groups in the MA units were all ionized at 0.9% aqueous NaCl. Tyagi et al . compared the swelling behaviors of synthesized P(HEMA/MA) hydrogels.…”

Characterization and use of ultraviolet‐reactive low‐molecular‐weight polyhydroxybutyrate to prepare biodegradable acrylates

“…Consequently, although the weight loss rates or the biodegradation rates of ACRY/LMWPHB increased with the LMWPHB content, they were also much smaller than those of pHEMA/LMWPHB and changed less drastically during the testing period, especially in the first 15 days. The results indicate that the biodegradation properties of various acrylate/LMWPHB copolymers could be modified and controlled by changes in the hydrophilic properties of the acrylic constituents and could generate many diversified applications, such as artificial skin manufacturing/dressings, marrow/spinal cord cell regeneration, drug delivery, scaffolds for cell adhesion and artificial cartilage production, and bone cements, as mentioned previously . The studied materials with the combined mechanical and biodegradation properties not only could result in bioactive and biodegradable second‐generation biomaterials but could also further result in third‐generation materials capable of stimulating specific cellular responses at the molecular level for new biomedical applications …”

“…In this study, the detailed chemical characterization of the prepared LMWPHB via the thermal treatment of PHB in a solvent and the use of LMWPHB to prepare different photopolymerized polyacrylates (hydrophobic and hydrophilic) were demonstrated. Polyacrylates are common materials that are popularly used in coatings, inks, commodity products, optical lenses [e. g., hydrophilic poly(hydroxyethyl methacrylate) (pHEMA) hydrogels for disposable contact lenses and treated hydrophobic pHEMA for traditional long‐wearing contact lenses], biomedical products [e.g., pHEMA used for artificial skin manufacturing/dressings, marrow/spinal cord cell regeneration, drug delivery, scaffolds for cell adhesion and artificial cartilage production and poly(methyl methacrylate) (PMMA) for bone cements], and so on . In general, polyacrylates may have biocompatibility, but they are not biodegradable.…”

Sustained release of potassium diclofenac from a pH‐responsive hydrogel based on gum arabic conjugates into simulated intestinal fluid

“…Over the last years, there is an increased interest on controlled release systems, owing to development of more potent drugs with high degree of specificity. New approaches on release systems are of essential importance because they provide relevant information both to build strategic synthesis of more advanced materials and to understand their properties, such as transport behavior of drug and water and interaction parameters.…”