Prolonged zero‐order BSA release from pH‐sensitive hydrogels of poly(AAc‐co‐DMAPMA) having rich nano through micro scale morphology

Abstract

New variety of pH-sensitive hydrogels, having macroporous interior with honey-comb type architecture and continuous skin at the surface, have been developed by single step aqueous copolymerization of acrylic acid (AAc) and N-[3-(dimethylamino)propyl]-methacrylamide (DMAPMA) in different feed ratios at 41 AE 1 C. Interlocked nanogels of $ 300 nm were identified as the building blocks in all of these cylindrical poly(-AAc-co-DMAPMA) matrices (PDMAAc). The gels showed good compressive strength even at a swelling as high as 4330% (mass) at pH 7.0. Morphology of McCoy fibroblast cell line remained unchanged in direct contact with different PDMAAc gels, and cell viability (AESD) was recorded to be in the range of 105 (AE3)% to 87 (AE8)% after 72 h. Bovine serum albumin (BSA) loaded gels were prepared by means of equilibrium partitioning. Loading efficiency of PDMAAc gels has been found to be in the range of 210-277 mg/g dry gel. BSA release from PDMAAc gels at 37 C has been found to follow nonFickian diffusion mechanism in simulated gastric juice (pH 1.2), and Case II transport in simulated intestinal juice (pH 7.4). In vitro study showed that the gels are capable of retaining >95% of the loaded BSA in gastric medium through average gastric emptying period. Again, $ 56% BSA release was recorded in 24 h at pH 7.4, indicating prolonged BSA diffusion in intestinal condition. Constant rate of BSA diffusion was reflected from the release profiles at both the pH. Diffusion exponents also supported the same and indicated for absolute zero-order kinetics at pH 7.4.

Physically cross-linked pH-responsive hydrogels with tunable formulations for controlled drug delivery

“…In highly swellable gels the initial phase of volume variation follows zero-order swelling kinetics; hence Equation (3) is applied to derive the mechanism of volume variation at the initial phase (when the density of the device does not vary) of any polymerpenetrant system whatever the temperature and the penetrant activity. 22,47,54 Equation (3) is applicable for F ≤ 0.6 and the plots of ln(F) against ln(t) yield straight lines indicating up to almost 60% increase in the weight of the hydrogel. Equation (2) is termed as the Ritger-Peppas model and has been used frequently in literature.…”

“…calcium and zinc), which in turn affect the thermodynamic stability and the biological activity of calciumdependent proteolytic enzymes like trypsin and chymotrypsin. 47,48 A reduction in extracellular divalent ion concentration can also result in the opening of epithelial tight junctions, allowing paracellular drug transport across the intestinal epithelium. 48 Superabsorbent hydrogels of PAAc and its copolymers can swell tens to hundred times the original weight upon contact with the intestinal fluids, and can thereby tightly attach to the gut wall via mechanical fixation.…”

Solution properties of amphiphilic amino- and oligoethylene glycol-containing methacrylic copolymers

“…Часто для этого используются аминосодержащие N-диалкиламиноалкил(мет)акриламиды [6,7]. При этом в большинстве исследований получаемые полимеры рассматриваются в качестве pH-чувствительных материалов для доставки лекарственных средств [8,9]. Полимеры были синтезированы методом радикальной полимеризации в толуоле при 70°С.…”

pH‐responsive poly(DMAPMA‐co‐HEMA)‐based hydrogels for prolonged release of 5‐fluorouracil

“…Poly( N [‐3(dimethylamino)propyl] methacrylamide) (PDMAPMA), on the other hand, is believed to be temperature responsive in nature but mechanical properties of the gels are not good enough to be used in drug release formulations 22. Recently, a few reports have been published on PDMAPMA hydrogels for various drug and protein release applications 23–26…”