Phases in the temporal multiscale evolution of the drug release mechanism in IPN-type chitosan based hydrogels

Abstract

The study proposes modeling calcein release kinetics (considered as a hydrophilic drug model) from an interpenetrating network matrix of hydrogels, based on the combination of two polymers, of which chitosan is the most commonly used polymer. The release process is analyzed for different increasing time intervals, based on the evolution of the release kinetics. For each time interval, a dominant release mechanism was identified and quantitative analyses were performed, to probe the existence of four distinct stages during its evolution with each stage governed by a different kinetics model. An interesting and original aspect, which is analyzed through a novel approach, is that of drug release at longer time scales, which is often overlooked. It revealed that the system behaves as a complex one and its evolution can be described through a nonlinear theoretical model, which offers us new insights into its order-disorder evolution.

Coacervation of Interfacial Adhesive Proteins for Initial Mussel Adhesion to a Wet Surface

“…The first possible driving force is a salt‐bridge. Anions can cause electrostatic attraction and bridge between positively charged amino acids via ionic cross‐linking, such as chitosan hydrogels formed by ionic cross‐linking between sulfate and amine groups . The guanidinium moiety of arginine strongly interacts with dihydrogen sulfate, as well as phosphate and citrate, which are large negative salts.…”

Aspects Regarding the Pharmaceutical Waste Management in Romania

“…Due to the fact that sewerage systems are not properly equipped to eliminate medicines and their compounds in an efficient way, they can be released in water courses and then get into the drinking water supply system [14] (Figure 1). Medicines used in the treatment and prevention of diseases in humans and animals are extremely important healthcare tools for society, designed to exhibit specific biological effects in the human or animal body, whose evolution is still under research [15][16][17][18][19]. However, the effects of their interaction, in the environment, with non-target organisms, where they come in the form of metabolites excreted by human or animal organisms that consume them or by the inappropriate disposal of unused medicinal products, are very little understood or even unknown [20].…”

Possible Dynamics of Polymer Chains by Means of a Ricatti s Procedure - an Exploitation for Drug Release at Large Time Intervals

“…The statement becomes clearer if we put our system in its matrix form: (3) As long as M, R, K have constant values, this matrix equation, written in an equivalent form evidences the position of the energy and thus of the Hamiltonian. Indeed, from equation (3) we can obtain: (4) which proves that the energy in its quadratic form (the right part of equation (4)) is the variation rate of the physical action represented by the elementary area from the phase space. We would like to showcase here is the fact that the energy does not have to obey the conservation laws in order to act like a variation rate for the physical action.…”

“…Hydrogels based on polymers (high and medium molecular weight chitosan, poly(vinyl alcohol), glutaraldehyde), cross-linked with sodium sulphate or sodium tripolyphosphate were prepared following the method detailed in [4]. The hydrogels composition was modified in order to optimize of their properties, in terms of mechanical stability and drug release.…”

“…The hydrogels composition was modified in order to optimize of their properties, in terms of mechanical stability and drug release. The hydrogels were loaded with calcein and the amount of released drug was monitorized, observing for large time intervals a decrease of released calcein [4].…”