Porosity and dielectric properties as tools to predict drug release trends from hydrogels

Abstract

Conventional studies on hydrogel properties such as viscosity, pH and swelling provide information without treating the components of hydrogel, viz., water and polymer individually. Water and hydrophilic polymers need to be studied individually to understand their relationship with each other to relate their influence on drug release. In this context, we have assigned the combination of porosity and dielectric properties as tools to explore the hydrogels. Porosity and dielectric properties have been analyzed using thermoporometry and alternative current impedance measurements, respectively. A well-known hydrogel genipin cross linked gelatin-chitosan (GC) composite, with catechin as model drug has been studied. The increasing concentration of chitosan in the hydrogel composites led to increase in bound water content and incorporation of charge entrapping moieties. Controlled and medium drug release are observed for GC1 whereas the native hydrogels and composites with lower ratio of chitosan yield immediate release and composites with higher ratio effects in slow release for limited duration (9 hours) of drug delivery process. This trend of drug release is in accordance with the results obtained from porosity and dielectric properties where reduction in pore radii to lower range and increase in relaxation time of polymeric components were observed at higher concentration of chitosan. Thus, these properties can be judiciously used for predicting drug release and designing biomaterials according to it.

Characterization of Tuna Gelatin-Based Hydrogels as a Matrix for Drug Delivery

“…The drug release profiles of tuna gelatin hydroge in PBS buffer at 30 °C exhibit similar triphasic behavior for both drugs with a significan burst release during the first 5 h (≈5%), probably related to the drug molecule encapsulated in the gelatin pores as observed by cryo-SEM (Figure 18). Thereafter, tw different pseudo-first-order release profiles were reached for both molecules, an initia faster release within the first 5 to 24 h and a slower release from 24 h onwards wit different release rates for both antitumoral that could be associated with the disruption o physically cross-linked gelatin network [63]. The burst release is similar for both drugs, i agreement with the physical trap within the porous network.…”

“…The measured SAXS profile intensity (I(q)) were adjusted to an interacting disk-like shape model [69] described by a structure factor of hard-disk mixtures resolved by an analytic theory resulting from a free-energy functional for the inhomogeneous hard-disk fluid [70]. The pores observed by cryo-SEM suggested a random uniform distribution that was previously modelled [71] with the hard-disk structure factor (Equations ( 2) and ( 3)) [63] to consider the scattering interference aroused from the different pores by interpolating the analytical solution of a two-dimensional mixture of inhomogeneous discs from the analytical cases of one and three dimensions and with the structure factor defined as:…”

Synthesis and characterization of a photocrosslinkable chitosan–gelatin hydrogel aimed for tissue regeneration

“…27,51 These ndings could be correlated with the content of bound water, which increases depending on the degree of crosslinking and with the composition of polymeric components as already described by Raja and Fathima. 59 Furthermore, this study also mentions that a higher amount of chitosan in the hydrogels increases bound water content as -NH 2 and -OH groups, located in each N-acetyl-glucosamine and glucosamine residues of the polymer backbone interact with water molecules via hydrogen bonding. In accordance with this evidence, Thein-Han and co-workers also concluded that chitosan scaffolds present a higher capacity to retain water than chitosan-gelatin scaffolds.…”

Application of Gelatin Derived from Waste Tilapia Scales to an Antibiotic Hydrogel Pad

“…The pore structure determined by SEM provides the information on surface related to biological properties such as permeability. Porosity can be used as a tool to predict drug release in biomaterial application [11]. Rough surface with hollow cells were observed from gelatin derived from using lime acid hydrolysis (Fig.…”