Drug Release Behavior Of Hydrogels Research Articles

Dual effect of procaine-loaded pectin hydrogels: pain management and in vitro wound healing

This study aims to develop procaine-loaded pectin hydrogels for both local anesthetic delivery and wound healing. We investigated the effects of initial drug concentration, pH of initial drug solution, and drying temperature of hydrogel on the drug release behavior of hydrogels. Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy were used for their characterization. Their swelling percentage, drug loading, and drug release behaviors were determined. Toxic effects of selected hydrogels on the wound healing ability of PCS-201-012 human dermal fibroblast cells and wound dressing properties were also investigated. According to our results, the hydrogels did not affect cell migration. Initial drug concentration, pH of initial drug solution, and drying temperature of hydrogels are crucial on procaine release behavior of pectin-based hydrogels.

Effects of cellulose nanocrystal polymorphs and initial state of hydrogels on swelling and drug release behavior of alginate-based hydrogels

In this work, composite hydrogels composed of sodium alginate (SA) and two crystal structures of cellulose nanocrystals (CNCs) I and II were prepared, respectively. Impacts of CNC polymorphs and initial state of the hydrogels on the swelling kinetics were analyzed on the basis of power law and Schott’s second-order kinetic equation. It was found that the swelling ratio of SA/1 CNC II was the largest, and it showed the non-Fickian diffusion behavior, while SA and SA/1 CNC I exhibited the Fickian diffusion behavior. And the swelling ratio of soaked hydrogels was great larger than that of the rinsed ones, but the swelling mechanism of the two situations was almost the same, that is, the Fickian diffusion behavior. In addition, drug release tests were performed in deionized water using chloramphenicol as a model drug. The results indicated that for the soaked hydrogels, the drug loading was high, while the release rate was slow. The reason for the higher loading but slower release rate was also discussed based on the morphology of hydrogels. On the other hand, the addition of CNC II into SA brought the high drug loading and slow release rate. It resulted from the strong hydrophilicity of CNC II and the strong interaction between drug and SA/CNC II hydrogels. This work could give a new promise for tuning the swelling and drug release behavior of hydrogels by varying the initial state of hydrogels or the crystal form of CNCs.

Injectable in situ dual-crosslinking hyaluronic acid and sodium alginate based hydrogels for drug release

A series of injectable in situ dual-crosslinking hydrogels (HA/ALG) based on oxidized sodium alginate (oxi-ALG) and hyaluronic acid modified with thiol and hydrazide (HA-SH/CDH) were prepared via hydrazone bonds and disulfide bonds. The chemical structures, morphologies, rheological properties, gelling time, swelling ratio, degradation rate and drug release behavior of hydrogels were investigated. HA/ALG hydrogels exhibited tunable gelling time, rheological properties, swelling ratio and degradation rate with varying precursor concentrations. The gelling time of HA/ALG hydrogels ranged from 157 s to 955 s, the values of yield stress of HA2/ALG2, HA3/ALG3 and HA4/ALG4 hydrogels were 1724, 4349 and 5306 Pa, and the degradation percentage of HA2/ALG2, HA3/ALG3 and HA4/ALG4 hydrogels were about 64%, 51% and 42% after incubating 35 days, respectively. Bovine serum albumin (BSA) was used as a model drug to investigate the drug controlled release properties, and the in vitro cumulative release percentage of BSA from HA2/ALG2, HA3/ALG3 and HA4/ALG4 drug-loaded hydrogels were about 79%, 72% and 69% after 20 days. The series of injectable in situ dual-crosslinking HA/ALG hydrogels could be an attractive candidate for drug delivery system, tissue engineering and regenerative medicine.

Magnetic nano carboxymethyl cellulose-alginate/chitosan hydrogel beads as biodegradable devices for controlled drug delivery

For the first time, nano carboxymethyl cellulose (NCMC) was synthesized via cellulose nanocrystal carboxymethylation. This nanomaterial was magnetized and used in bilayer alginate-chitosan hydrogel beads formulation to develop eco-friendly, smart, and magnetic sensitive hydrogel beads for the controlled pH-sensitive release of dexamethasone as a model drug. Water-soluble nanocrystalline cellulose (NCMC) and bilayer hydrogel beads were characterized in terms of size, surface morphology, surface modification, crystallinity, drug loading content, and in vitro drug release profile using various technics. Furthermore, the swelling behavior of hydrogels was examined and reported in three buffer media. The NCMCs improved drug loading capacity and swelling properties and also regulated drug release behavior of hydrogels. The hydrogel beads swelling specification exhibited a higher index in phosphate buffer at pH 5.8 than at pH 1.2 and 7.4. Besides, in vitro release of beads revealed excellent pH-sensitive drug release profiles and prevented release in the gastrointestinal tract. The beads showed high pH sensitivity for dexamethasone drug in pH 5.8 in compared to other pH media. The obtained results could introduce hydrogel beads as a high potential drug delivery system.

Influence of sonication treatment on supramolecular cellulose microfibril-based hydrogels induced by ionic interaction

This study investigated effects of sonication treatment on characteristics and drug release behavior of hydrogels prepared by supramolecular cellulose microfibrils (CMFs) isolated by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation which made carboxylate negative charge available on the CMFs’ surface. The hydrogels were fabricated by inducing ionic interactions between negatively charged CMFs and a positive metal ion (Al3+). The sonication time showed no influence on the carboxylate content of CMFs, but it greatly influenced characteristics and drug release behavior of the hydrogels. These results indicate that the sonication time has an impact on hydrogels’ characteristics and drug release behavior.

Polysaccharide based hydrogels as controlled drug delivery system for GIT cancer

Keeping in view the anticancer nature of psyllium and methotrexate, psyllium, if suitably tailored to prepare the hydrogels, can act as the potential candidate for the slow drug delivery systems for GI tract. Therefore, the present study is an attempt to modify the psyllium for developing the hydrogels meant for delivery of methotrexate in controlled and sustained manner. The present article discusses the synthesis and characterization of the psy-cl-poly(AAm-co-AAc) hydrogels prepared by chemical crosslinking methods. These hydrogels have been characterized with SEMs, FTIR, TGA, XRD and swelling studies. The swelling and drug release behavior of hydrogels has been determined in solution of different pH. The results indicate that the drug release from the polymeric matrix follows Fickian diffusion mechanism in pH 7.4 buffer.

Synthesis of Starch-g-poly (acrylic Acid-co-2-hydroxy Ethyl Methacrylate) as Potential pH-sensitive Hydrogel-based Drug Delivery System

The present work focused on the design of drug delivery system (DDS) based on a pH-sensitive hydrogel. The hydrogels were prepared via graft copolymerization of mixtures of acrylic acid (AA) and 2-hydroxy ethyl methacrylate (HEMA) onto starch backbones by a free radical polymerization technique. Sodium bicarbonate (NaHCO3) was added to function as a foaming agent under acidic conditions, rendering the hydrogels to be porous. Porous structure of hydrogel was essential in this system to yield a large surface area so that 5-fluorouracil (5-FU) release could be facilitated. The hydrogel thus prepared possessed a porous structure as determined by scanning electron microscopy. Due to the reversible swelling behavior of the hydrogels, the synthesized networks can sense the environmental pH change and achieve an oscillatory release pattern. Using drug 5-FU as a model molecule, the in vitro controlled drugrelease behaviors of these hydrogels were investigated. The results indicate that the main parameter affecting the drug-release behavior of hydrogels is the pH of the solution. The release rate of 5-FU from hydrogel at pH 7.4 was faster than that at pH 1.2 due to the shrinkage of the hydrogel at pH 1.2.These results suggest that a porous hydrogel could potentially be a useful local delivery system to release drugs primarily at a specific site of body.

Novel physically crosslinked hydrogels of carboxymethyl chitosan and cellulose ethers: Structure and controlled drug release behavior

AbstractNovel hydrogels, physically crosslinked by hydrogen bonding of component polymers, were obtained by mixing aqueous solutions of carboxymethylchitosan (CMCS) with cellulose ethers including hydroxyethylcellulose (HEC) and methylcellulose (MC). The hydrogels were characterized by IR, XPS, WAXD, and SEM. The swelling and controlled drug release behaviors of hydrogels were also studied. The results indicate that intermacromolecular hydrogen bonding in CMCS/HEC is stronger than that in CMCS/MC. The swelling and drug release rate of hydrogels decrease as the interaction of component polymers increases. Both the swelling and drug release from hydrogels can be controlled by component polymer ratio. The hydrogels may be potential candidates for biomedical applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Radiation synthesis of poly[(dimethylaminoethyl methacrylate)-co-(ethyleneglycol dimethacrylate)] hydrogels and its application as a carrier for anticancer delivery

The use of hydrogels as carriers for anticancer delivery has been a subject of significant recent research. In our recent work, we have shown that diffusion-controlled delivery of flutamide from hydrogels containing poly (dimethylaminoethyl methacrylate (DMAEMA)/ethyleneglycol dimethacrylate (EGDMA)) can be possible and controlled by the three-dimensional structure. Hydrogels based essentially on dimethylaminoethyl methacrylate and different ratios of ethyleneglycol dimethacrylate monomers were synthesized using gamma radiation copolymerization. The influence of copolymer composition and pH value of the surrounding medium on swelling behavior into the glassy polymer were discussed. The results showed that the ratio of EGDMA in the comonomer feeding solution has a great effect on the gel fraction and water content in the final hydrogel. In this regard, it was observed that the increase of EGDMA ratio decreased these properties. The ability of the prepared copolymer to be used as drug carrier for anticancer drug-delivery system was estimated using flutamide as a model drug. In vitro drug-release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and DMAEMA content of hydrogel.

Adsorption and controlled release of Chlortetracycline HCl by using multifunctional polymeric hydrogels

Adsorption and controlled release of Chlortetracycline HCl to and from multifunctional polymeric materials (HEMA/MAA) hydrogels were investigated. P(HEMA/MAA) hydrogels were synthesized by gamma radiation-induced copolymerization of 2-hydroxyethylmethacrylate (HEMA) and methacrylic acid (MAA) in aqueous solution. The influence of copolymer composition and pH value of the surrounding medium on the type of water diffusion into the glassy polymer were discussed. Drug, Chlortetracycline HCl containing hydrogels, with different drug concentration to polymer ratios, was loaded by direct adsorption method. The influence of MAA content in the gel on the adsorption capacities of hydrogel was studied. Chlortetracycline HCl adsorption capacity of hydrogels was found to increase from 8 to 138 mg Chlortetracycline HCl per gram dry gel with increasing amount of MAA in the gel system and drug concentration. The effect of pH on the releasing behavior of Chlortetracycline HCl from gel matrix was investigated. In vitro drug release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and MAA content of hydrogel.

Preparation of poly( N-isopropylacrylamide/itaconic acid) copolymeric hydrogels and their drug release behavior

N-isopropylacrylamide/itaconic acid copolymeric hydrogels were prepared by irradiation of the ternary mixtures of N-isopropylacrylamide/itaconic acid/water by γ-rays at ambient temperature. The effect of comonomer concentration, irradiation dose and pH on the swelling equilibria were studied. Lidocaine was used as a model drug for the investigation of drug release behaviour of hydrogels. Lidocaine adsorption capacity of the hydrogels were found to increase from 3.6 to 862.1 (mg lidocaine/g dry gel) with increasing amount of itaconic acid in the gel structure. Adsorption and release processes were followed at 4 and 37 °C, respectively. The release studies showed that the basic parameters affecting the drug release behaviour of the hydrogels were pH and temperature of the solution and cross-link density of the gels.

Controlled release of terbinafine hydrochloride from pH sensitive poly(acrylamide/maleic acid) hydrogels

Adsorption and controlled release of terbinafine hydrochloride (TER-HCl) to and from pH sensitive poly(acrylamide/maleic acid) (P(AAm/MA)) hydrogels were investigated. P(AAm/MA) hydrogels were prepared by irradiating the ternary mixtures of AAm/MA/and water by γ-rays at ambient temperature. Antifungal drug, TER-HCl containing hydrogels, at different drug to polymer ratios, was prepared by direct adsorption method. The influence of MA content in the gel on the adsorption capacities of hydrogel and the effect of pH on the releasing behavior of TER-HCl from gel matrix were investigated. Terbinafine adsorption capacity of hydrogels are found to increase from 2 to 38 mg TER-HCl per g dry gel with increasing amount of MA in the gel system. In vitro drug release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and MA content of hydrogel.

Radiation synthesis of poly(N-vinyl 2-pyrrolidone/itaconic acid) hydrogels and their controlled release behaviours

N-vinyl 2-pyrrolidone/itaconic acid copolymeric hydrogels were prepared by irradiating the ternary mixtures of N -vinyl 2-pyrrolidone/itaconic acid/water by γ-rays at ambient temperature. For the characterization of network structure of these hydrogels, swelling properties in phosphate buffer solutions and molecular weight between crosslinks were investigated. Methylene Blue was used as a model drug for the investigation of controlled release behaviour of hydrogels. Specific Methylene Blue adsorption capacity of hydrogels are found to increase from 0.36 to 47.7 (mg MB/g gel) with increasing amount of itaconic acid in the gel system. The influence of molecular weight between cross-links, the concentration of ionizable groups, ionization and concentration of MB in the hydrogel were examined. The release studies show that one of the basic parameters affecting the drug release behaviour of hydrogels is the pH of the solution.