Numerical Simulation Of Swelling And Drug Release Processes Of Weak Polyelectrolyte Hydrogel In Acid-Salt Solution

Hydrogel is a kind of polymer with three-dimensional crosslinked network structure,which contains a large amount of solvent.They can absorb large amount of solvent to swell but insoluble in solvent.Besides,they can also collapse after lossing solvent.Weak polyelectrolyte hydrogel can respond quickly according to the variation of external pH value,the main mechanism is that carboxylic acid group(-COOH)are existed in this kind of hydrogels.When pH changed,these groups can ionize or recombine the hydrogen ions inside the system quickly,causing the exclusion or attract effects between macromolecular chains in hydrogels network,giving rise to the volume change of hydrogels.The fundamental purpose of drug delivery in biological body is to obtain effective and low-toxicity drug treatment,that is,the drug can be concentrated in the target area,and release certain amount and maintain a certain amount of time.Weak polyelectrolyte hydrogels can be applied to the carriers of drug release due to the unique biocompatibility,oxygen permeability,soft comfortability and can respond more quickly and sensitively contrapose the small changes in the environment.In recent years,the mathematical modeling of drugs has continuously improved its importance.With the development of computer science,using computer simulation technology can significantly reduce the experimental research in product development process,save product development time greatly and reduce production cost immensely.In addition,the potential biological phenomena can be quantitatively analyzed in the process of drug control release basing on the simulation results,thus the analysis results can be fed back to the release process of the drugs to elucidate the potential drug release mechanism.Therefore,it is necessary to build mathematical model and carry out numerical simulation of hydrogel swelling and drug release process of weak polyelectrolyte hydrogel,and then to study the mechanisms of weak polyelectrolyte hydrogel.In this work,basing on the triphase model,Langmuir isothermal adsorption equation and drug release equation was combinated to established complete model for weak polyelectrolyte hydrogel.By means of mathematical modeling and finite element method,the swelling and drug release of weak polyelectrolyte hydrogel in acid salt solution were simulated.Using finite element method,the influence of the material parameters on swelling and drug release in the case of drugs were homogeneously distributed within the weak polyelectrolyte hydrogels.;The mechanism of drugs released from weak polyelectrolyte hydrogels in different stages was also explored;Aiming at the inhomogeneous drugs dispersion in weak polyelectrolyte hydrogel,the effects of different distribution patterns of drugs on drug release were investigated,and then the impacts of drug distribution modes within the hydrogels which consist of homogeneous distribution and inhomogeneous distribution(sinusoidal distribution and cosine distribution)on swelling and drug release were comprehensively compared.Through the above research,the release mechanism of weak polyelectrolyte hydrogel was revealed,and the process of hydrogel release was predicted,which facilitated the application of hydrogels as drug carrier in the field of biomedicine.