Gallic acid loaded disulfide cross-linked biocompatible polymeric nanogels as controlled release system: synthesis, characterization, and antioxidant activity

Abstract

In this article, a sustained release formulation of the antioxidant gallic acid (GA) is presented in the form of glutathione responsive disulfide cross-linked poly(ethylene glycol)-based nanogels synthesized via aqueous inverse miniemulsion using atom transfer radical polymerization. The particle size was found to be in the range from 227 ± 51.78 to 573.3 ± 207.2 nm at three drug loading levels achieved i.e. 6.6, 14.26, and 18.29 wt.% of the nanogels with loading efficiency in the range of 60-70%. The release profile of the GA studied at three drug loading levels suggested a controlled release and the nanogels were capable of scavenging radicals and retained the antioxidant activity. The GA-loaded nanogels were found to be biocompatible on human cervical cancer cell lines (HeLa). DCFH-DA (2,7-dichlorofluorescin diacetate) assay evidenced that the nanogels were capable of scavenging the reactive oxygen species in cellular environment.

Synthesis and Characterization of Poly(2-hydroxyethylmethacrylate) Contact Lenses Containing Chitosan Nanoparticles as an Ocular Delivery System for Dexamethasone Sodium Phosphate

“…A linear relationship was also obtained in the case of the Higuchi and Hixson-Crowell equations and hence, drug release kinetics of this type may be governed by a mechanism involving erosion/diffusion, a change in surface area and diameter of the nanoparticles, as well as a change in diffusion path length during the release process. The applicability of all these equations further reveal that more than one mechanism is involved for the release of DXP from chitosan nanoparticles, as also indicated by the diffusion exponent value (n~0.8) from the Korsmeyer-Peppas equation [34]. Similar release behaviour has been observed previously by other groups on different systems, where the KorsmeyerPeppas equation has been applied along with other mathematical models to confirm the anomalous release mechanism from the value of the diffusion exponent 'n' [42,[45][46][47][48].…”

“…35 days. This may be attributed to the higher initial concentration of the DXP inside the particles maintaining a higher diffusion gradient, which gradually decreased with time [34]. The release rate was found to increase with an increase in initial drug loading from 20 to 50 wt%, corresponding to 4.19 and 10.65% loading capacities, respectively.…”

“…However this increasing trend in release rate was not observed in nanoparticles with higher initial drug loading of 100 wt%, corresponding to 43.06% loading capacity, where nearly 65% release was observed in 20 days. The increasing trend of release rate with increase in loading capacity is a common phenomenon [35,36] and could be due to the increasing concentration gradient of drug between the nanoparticles and the release medium [34]. As well as this, release rate has also been reported to depend on cross-linker concentration [31], polymer molecular weight and particle size [30,37].…”

A Comprehensive Outlook of Synthetic Strategies and Applications of Redox‐Responsive Nanogels in Drug Delivery

“…Results obtained from cytotoxicity assay on HeLa cells indicated that DOX‐loaded nanogels were nontoxic before the addition of GSH till 48 h but significantly inhibited the cell growth after the addition of GSH in next 72 and 96 h due to the release of DOX from nanogel matrix following degradation. The nanogels have also been utilized for the delivery of antioxidants gallic acid, ellagic acid, and chlorin e6 (Ce6) mediated photodynamic therapy . Both gallic acid and ellagic acid were capable of scavenging ROS in the cellular environment.…”

Preparation of camphor oil/latex dispersion for the control of camphor oil release

“…During the process of polymerization, particle nucleation occurs primarily within monomer droplets which are stabilized against coalescence and diffusion degradation by emulsifiers and co-stabilizers, and as such reduces the size of the monomer droplet in a range of 50-200 nm with shear forces [8,9,[11][12][13][14][15][16]. However, emulsifiers commonly used in miniemulsion polymerization are problematic for producing stable dispersions because they are easily desorbed from the surface of the particle, especially at high temperatures [16][17][18][19][20].…”