Phases in the temporal multiscale evolution of the drug release mechanism in IPN-type chitosan based hydrogels (original) (raw)
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Materiala Plastice, 2016
In order to analyze the effect induced by encapsulating the drug in liposomes, comparative studies were performed for control hydrogels and complex systems (the same hydrogels containing liposomes). The results showed that the use of liposomes entrapped within chitosan hydrogels allows a strong decrease of burst effect and, moreover, the mechanism of drug release is a complex Fickian diffusion, consisting of drug diffusion through the swollen hydrogel and/or water filled pores, being continuously fed by calcein loaded in liposomes.
Computational and Mathematical Methods in Medicine, 2019
Drug release is a complex phenomenon due to the large number of interdependent side effects that occur simultaneously, involving strong nonlinear dynamics. Therefore, since their theoretical description is difficult in the classical mathematics modelling, we have built a theoretical model based on logistic type laws, validated by the correlations with the experimental data, in a special case of drug release from hydrogels. The novelty of our approach is the implementation of multifractality in logistic type laws, situation in which any chaotic system, characterized by a small number of nonlinear interactions, gets memory and, implicitly, characterization through a large number of nonlinear interactions. In other words, the complex system polymer-drug matrix becomes “pseudo-intelligent.”
Liposome loaded chitosan hydrogels. A promising delayed release kinetics mechanism
Frontiers in Bioengineering and Biotechnology, 2016
In order to analyze the effect induced by encapsulating the drug in liposomes, comparative studies were performed for control hydrogels and complex systems (the same hydrogels containing liposomes). The results showed that the use of liposomes entrapped within chitosan hydrogels allows a strong decrease of burst effect and, moreover, the mechanism of drug release is a complex Fickian diffusion, consisting of drug diffusion through the swollen hydrogel and/or water filled pores, being continuously fed by calcein loaded in liposomes.
Modeling the Drug Release from Hydrogel-Based Matrices
Molecular Pharmaceutics, 2014
In this work the behavior of hydrogel-based matrices, the most widespread systems for oral controlled release of pharmaceuticals, has been mathematically described. In addition, the calculations of the model have been validated against a rich set of experimental data obtained working with tablets made of hydroxypropyl methylcellulose (a hydrogel) and theophylline (a model drug). The model takes into account water uptake, hydrogel swelling, drug release, and polymer erosion. The model was obtained as an improvement of a previous code, describing the diffusion in concentrated systems, and obtaining the erosion front (which is a moving boundary) from the polymer mass balance (in this way, the number of fitting parameters was also reduced by one). The proposed model was found able to describe all the observed phenomena, and then it can be considered a tool with predictive capabilities, useful in design and testing of new dosage systems based on hydrogels.
Journal of Controlled Release, 1994
Model calculations have been performed to account for the kinetics of drug release from polymeric matrices where both diffusion and desorption mechanisms control the overall release rate. The model incorporates both a desorption term, based on Langmuir kinetics, and a transient Fickian diffusion term and is solved for infinite sink boundary conditions. Solutions by both finite difference and finite element techniques indicate the effects of binding interaction strength, binding capacity, amount of drug loaded and rate of desorption on the release kinetics of drugs adsorbed to polymer matrices. Simulation results indicate that it is possible to modulate the net release rates of drugs over a wide range by altering the binding parameters enumerated above as well as drug diffusivities in the matrix.
Parametric simulation of drug release from hydrogel-based matrices
Journal of Pharmacy and Pharmacology, 2012
In this work a model recently proposed to describe the drug release from hydrogel-based matrices was applied to describe the fractional drug release from matrices based on hydroxypropylmethylcellulose (HPMC) and diclofenac. Methods The model, firstly proposed to describe the behaviour of systems based on HPMC and theophylline and a single set of preparation variables, is based on mass balances and transport phenomena evaluation and it was solved by an FEM-based numerical code. The experimental data on the HPMC-diclofenac matrices, taken from literature, have been obtained by varying the drug loading ratio, the compression force, the powder size of both the drug and the polymer. Key findings A good agreement between experimental data and model predictions, as calculated in the present work, was obtained without the use of any adjustable parameters. Conclusions The predictive nature of the model has been confirmed, even changing the drug molecule and other preparative parameters.
Journal of Polymer Research, 2020
Due to in-situ gelation, an injectable hydrogel drug carrier has advantages over other delivery systems. Atomic simulations help to study the structure-performance relationship of drug delivery systems (DDS) considering the interaction between components, which is focused in this study. Chitosan hydrogel network is constructed using three different crosslinking agents, soaked with water, and thermal cycles are applied to estimate the critical temperatures. Subsequently, three different drug molecules are incorporated into the models separately and the distributions are observed by analyzing the trajectories of the drug molecules obtained from the simulations performed with canonical ensembles, as the distributions will affect the drug discharge. Afterward, a proteinassociated with cancer is added to the supercell and the diffusion of the drug is observed in the presence of protein molecules. A better system consisting of the drug molecules and differently cross-linked hydrogels is recommended in this study in terms of the diffusivity of the drug molecules out of nine distinct systems.
Controlled Release of Drugs FromHydrogel Based Matrices Systems: Experiments and Modeling
2012
Hydrogels are materials largely used in the formulation of pharmaceuticals since, in principle, they could produce a release system of zero-order kinetics, which is of great therapeutic interest. In this paper, a model was proposed for the description of the main transport phenomena involved in the drug release process from hydrogel matrices (water diffusion, polymer swelling, drug diffusion and polymer dissolution); the model predictions are successfully compared with a large set of experimental data, obtained working with matrices systems based on HPMC (Hydroxy Propyl Methyl Cellulose). The proposed model was found able to reproduce main features of the observed phenomena, it can thus be adopted for prediction of the performances of drug release systems from hydrogel matrices.
Controlled drug release from hydrogel-based matrices: experiments and modeling
International journal of pharmaceutics, 2015
Controlled release by oral administration is mainly achieved by pharmaceuticals based on hydrogels. Once swallowed, a matrix made of hydrogels experiences water up-take, swelling, drug dissolution and diffusion, polymer erosion. The detailed understanding and quantification of such a complex behavior is a mandatory prerequisite to the design of novel pharmaceuticals for controlled oral delivery. In this work, the behavior of hydrogel-based matrices has been investigated by means of several experimental techniques previously pointed out (gravimetric, and based on texture analysis); and then all the observed features were mathematically described using a physical model, defined and recently improved by our research group (based on balance equations, rate equations and swelling predictions). The agreement between the huge set of experimental data and the detailed calculations by the model is good, confirming the validity of both the experimental and the theoretical approaches.