Wound healing evaluation of sodium fucidate-loaded polyvinylalcohol/sodium carboxymethylcellulose-based wound dressing

The cross-linked hydrogel films containing sodium fucidate were previously reported to be prepared polyvinyl alcohol (PVA) and sodium carboxymethylcellulose (Na-CMC) using the freeze-thawing method and their physicochemical property was investigated. For the development of novel sodium fucidate-loaded wound dressing, here its in vivo wound healing test and histopathology were performed compared with the conventional ointment product. In wound healing test, the sodium fucidate-loaded composed of 2.5% PVA, 1.125% Na-CMC and 0.2% drug showed faster healing of the wound made in rat dorsum than the hydrogel without drug, indicating the potential healing effect of sodium fucidate. Furthermore, from the histological examination, the healing effect of sodium fucidate-loaded hydrogel was greater than that of the conventional ointment product and hydrogel without drug, since it might gave an adequate level of moisture and build up the exudates on the wound area. Thus, the sodium fucidate-loaded wound dressing composed of 5% PVA, 1.125% Na-CMC and 0.2% drug is a potential wound dressing with excellent wound healing.     

PVA-PEG physically cross-linked hydrogel film as a wound dressing: experimental design and optimization

The development of hydrogel films as wound healing dressings is of a great interest owing to their biological tissue-like nature. Polyvinyl alcohol/polyethylene glycol (PVA/PEG) hydrogels loaded with asiaticoside, a standardized rich fraction of Centella asiatica, were successfully developed using the freeze–thaw method. Response surface methodology with Box–Behnken experimental design was employed to optimize the hydrogels. The hydrogels were characterized and optimized by gel fraction, swelling behavior, water vapor transmission rate and mechanical strength. The formulation with 8% PVA, 5% PEG 400 and five consecutive freeze–thaw cycles was selected as the optimized formulation and was further characterized by its drug release, rheological study, morphology, cytotoxicity and microbial studies. The optimized formulation showed more than 90% drug release at 12?hours. The rheological properties exhibited that the formulation has viscoelastic behavior and remains stable upon storage. Cell culture studies confirmed the biocompatible nature of the optimized hydrogel formulation. In the microbial limit tests, the optimized hydrogel showed no microbial growth. The developed optimized PVA/PEG hydrogel using freeze–thaw method was swellable, elastic, safe, and it can be considered as a promising new wound dressing formulation.     

Development of polyvinyl alcohol-sodium alginate gel-matrix-based wound dressing system containing nitrofurazone

Polyvinyl alcohol (PVA)/sodium alginate (SA) hydrogel matrix-based wound dressing systems containing nitrofurazone (NFZ), a topical anti-infective drug, were developed using freeze-thawing method. Aqueous solutions of nitrofurazone and PVA/SA mixtures in different weight ratios were mixed homogeneously, placed in petri dishes, freezed at -20 degrees C for 18h and thawed at room temperature for 6h, for three consecutive cycles, and evaluated for swelling ratio, tensile strength, elongation and thermal stability of the hydrogel. Furthermore, the drug release from this nitrofurazone-loaded hydrogel, in vitro protein adsorption test and in vivo wound healing observations in rats were performed. Increased SA concentration decreased the gelation%, maximum strength and break elongation, but it resulted into an increment in the swelling ability, elasticity and thermal stability of hydrogel film. However, SA had insignificant effect on the release of nitrofurazone. The amounts of proteins adsorbed on hydrogel were increased with increasing sodium alginate ratio, indicating the reduced blood compatibility. In vivo experiments showed that this hydrogel improved the healing rate of artificial wounds in rats. Thus, PVA/SA hydrogel matrix based wound dressing systems containing nitrofurazone could be a novel approach in wound care.     

Accelerated wound healing and anti-inflammatory effects of physically cross linked polyvinyl alcohol–chitosan hydrogel containing honey bee venom in diabetic rats

Diabetes is one of the leading causes of impaired wound healing. The objective of this study was to develop a bee venom-loaded wound dressing with an enhanced healing and anti-inflammatory effects to be examined in diabetic rats. Different preparations of polyvinyl alcohol (PVA), chitosan (Chit) hydrogel matrix-based wound dressing containing bee venom (BV) were developed using freeze–thawing method. The mechanical properties such as gel fraction, swelling ratio, tensile strength, percentage of elongation and surface pH were determined. The pharmacological activities including wound healing and anti-inflammatory effects in addition to primary skin irritation and microbial penetration tests were evaluated. Moreover, hydroxyproline, glutathione and IL-6 levels were measured in the wound tissues of diabetic rats. The bee venom-loaded wound dressing composed of 10 % PVA, 0.6 % Chit and 4 % BV was more swellable, flexible and elastic than other formulations. Pharmacologically, the bee venom-loaded wound dressing that has the same pervious composition showed accelerated healing of wounds made in diabetic rats compared to the control. Moreover, this bee venom-loaded wound dressing exhibited anti-inflammatory effect that is comparable to that of diclofenac gel, the standard anti-inflammatory drug. Simultaneously, wound tissues covered with this preparation displayed higher hydroxyproline and glutathione levels and lower IL-6 levels compared to control. Thus, the bee venom-loaded hydrogel composed of 10 % PVA, 0.6 % Chit and 4 % BV is a promising wound dressing with excellent forming and enhanced wound healing as well as anti-inflammatory activities.     

Synthesis and Charactersiation of Chitosan conjugate; Design and Evaluation of Membrane Moderated Type Transdermal Drug Delivery System

The purpose of the present research investigation was to synthesis, characterisation of chitosan conjugates and its effect on drug permeation from transdermal rate controlling membrane. Chitosan conjugate was synthesised by conjugation with thioglycolic acid. The prepared chitosan conjugate was characterised by determining the charring point, Fourier transmission-infrared and differential scanning calorimetric analysis. The rate controlling membranes were prepared by various proportions of chitosan and chitosan conjugate, to moderate drug permeation through rate controlling membrane. The membrane moderated transdermal system consists of reservoir to hold the drug gel was prepared by 20% w/v ethylcellulose with a cavity in its center. An impermeable backing layer was prepared by 2% w/v ethylcellulose. Gel consists of carvedilol was prepared by sodium alginate and sodium carboxymethylcellulose in ethanol:water solvent system The rate controlling membranes prepared were evaluated by various parameters like thickness, folding endurance, swelling index, moisture content, moisture uptake, water vapor transmission rate, tensile strength test, measurement of gel strength, in vitro permeation study, ex vivo permeation study, compatibility study using differential scanning calorimetry and stability studies. All physical parameters evident that prepared membranes have good folding endurance and sufficient tensile strength. As the proportion of chitosan conjugate increases in membrane swelling index, moisture content, moisture uptake and permeability coefficient increases. The gel strength of chitosan conjugate was considerable less compared with chitosan.     

Novel neomycin sulfate-loaded hydrogel dressing with enhanced physical dressing properties and wound-curing effect

To develop a novel neomycin sulfate-loaded hydrogel dressing (HD), numerous neomycin sulfate-loaded HDs were prepared with various amounts of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and sodium alginate (SA) using freeze-thawing technique, and their physical dressing properties, drug release, in vivo wound curing and histopathology in diabetic-induced rats were assessed. SA had a positive effect on a swelling capacity, but a negative effect on the physical dressing properties and drug release of HD. However, PVP did the opposite. In particular, the neomycin sulfate-loaded HD composed of drug, PVA, PVP and SA at the weight ratio of 1/10/0.8/0.8 had excellent swelling and bioadhesive capacity, good elasticity and fast drug release. Moreover, this HD gave more improved wound curing effect compared to the commercial product, ensured the disappearance of granulation tissue and recovered the wound tissue to normal. Therefore, this novel neomycin sulfate-loaded HD could be an effective pharmaceutical product for the treatment of wounds.     

基于壳聚糖/海藻酸钠-聚乙烯醇的双层复合水凝胶膜伤口敷料研究

目的 制备聚乙烯醇（PVA）/海藻酸钠（SA）-聚乙烯醇（PVA）/壳聚糖（CS）双层（PAPCS）水凝胶膜伤口敷料，并进行质量评价。方法 将PVA与SA以质量比2∶1混合，配制PVA/SA混合溶液；将PVA与CS分别以质量比1∶1、2∶1、3∶1、4∶1、5∶1混合，配制不同质量比的PVA/CS混合溶液；采用涂布法制备PAPCS双层水凝胶膜伤口敷料。通过水蒸气透过率、溶胀性能、保水性、力学性能、体外凝血性能和血液相容性考察对水凝胶膜的性能进行评价、筛选PVA与CS质量比；通过傅里叶变换红外光谱检测（FTIR）和扫描电子显微镜（SEM）对PAPCS水凝胶膜的结构和形貌进行表征；通过抑菌实验比较PAPCS以及PAPCS复合载碘交联环糊精金属有机骨架（I₂@COF@PAPCS）的体外抗菌性能。结果 PVA与CS质量比为2∶1时，PAPCS水凝胶膜综合性能较好。PAPCS水凝胶膜为多孔结构，具有良好的溶胀性能、保水性以及力学性能；PAPCS水凝胶膜的水蒸气透过率为（2 643.76±91.62）g·m^-2·d^-1，接近理想范围；与PVA/SA相比，PAPCS的凝血指数显著降低（P＜0.01），为（72.93±3.58）%，溶血率小于5%，具有促进血液凝固的能力且血液相容性良好；与PVA/SA相比，PAPCS对于金黄色葡萄球菌、大肠埃希菌均有明显抑制作用，抑菌圈直径分别为（11.89±0.22）、（12.28±0.25） mm；I₂@COF@PAPCS对金黄色葡萄球菌、大肠埃希菌的抑菌圈直径分别为（21.95±1.47）、（18.89±0.81）mm，抑菌效果显著优于PAPCS（P＜0.001）。结论 采用涂布法可成功制备双层PAPCS水凝胶膜敷料，其各项性能指标良好，具有明显的凝血、抑菌效果，与I₂@COF复合使用，抑菌作用进一步增强。     

Controlled release of dexamethasone from poly(vinyl alcohol) hydrogel

This study investigated a chemically crosslinked poly(vinyl alcohol) (PVA) hydrogel controlled drug delivery system to deliver the anti-inflammatory drug dexamethasone (DEX). The PVA hydrogels, with different crosslinking densities, were characterized by swelling studies, electron scanning microscopy, viscosity, Fourier transform infrared spectroscopy (FTIR) and in vitro release assessment. Increasing crosslinking density slowed and decreased swelling and water absorption. FTIR analysis suggested DEX has possible interactions with the crosslinker and the PVA polymer. In vitro release of DEX from PVA hydrogels was sustained for 33 days and appeared to fit the Higuchi and Korsmeyer–Peppas models. This work indicates the likelihood of PVA hydrogel as a controlled drug release system for DEX for anti-inflammatory uses.     

Drug release behaviors of a pH sensitive semi-interpenetrating polymer network hydrogel composed of poly(vinyl alcohol) and star poly[2-(dimethylamino)ethyl methacrylate

A series of pH sensitive semi-interpenetrating polymer network (semi-IPN) structural hydrogels composed of poly(vinyl alcohol) (PVA) and 21-arm star poly[2-(dimethylamino)ethyl methacrylate] (star PDMAEMA) with different molecular weight were prepared. Riboflavin was used as a model drug to evaluate the drug loading capacities and drug release behaviors of the semi-IPN structural hydrogels. The molecular weight of the star PDMAEMA polymers was calculated by GPC, and the formation of semi-IPN structure was confirmed by FTIR and SEM. It was found that the molecular weight of star PDMAEMA has significant effect on the structure, swelling ratio and drug release behaviors of the semi-IPN hydrogel at different pH conditions. The results suggested that the PVA/star PDMAEMA-50,000 hydrogel exhibited highest swelling ratio and drug loading capacity. The pH-sensitive semi-IPN hydrogel based on star PDMAEMA could be a promising drug delivery system due to the controllable porous structure.     

Evaluation of glucan/poly(vinyl alcohol) blend wound dressing using rat models

Aqueous mixture of beta-glucan and poly(vinyl alcohol) (PVA) was cast into films and dried at 110 degrees C without chemical crosslinking. The content of glucan in the film varied from 7% to 50%. The hydrophilicity of the resulting films was evaluated with swelling tests, wet area diffusion tests, and water vapor transmission tests. The swelling ratio, the wetting ratio, and the water vapor transmission rate increased with the glucan content. When contacting water, glucan was released, and the percent release of glucan increased with the glucan content. The addition of glucan made the film more ductile than pure PVA. The results of hemocompatibility test showed no significant effect on the activated partial thromboplastin time (APTT) and thrombin time (TT) and minor adsorption of human serum albumin (HSA). On observing the wound healing of rat skin, the healing time was shortened by 48% using PVA/glucan film comparing to cotton gauze. Therefore, a wound dressing made of PVA/glucan can greatly accelerate the healing without causing irritation.     

Electrically controlled release of sulfosalicylic acid from crosslinked poly(vinyl alcohol) hydrogel

Electrically controlled drug delivery using poly(vinyl alcohol) (PVA) hydrogels as the matrix/carriers for a model drug was investigated. The drug-loaded PVA hydrogels were prepared by solution-casting using sulfosalicylic acid as the model drug and glutaraldehyde as the crosslinking agent. The average molecular weight between crosslinks, the crosslinking density, and the mesh size of the PVA hydrogels were determined from the equilibrium swelling theory as developed by Peppas and Merril, and the latter data were compared with those obtained from scanning electron microscopy. The release mechanisms and the diffusion coefficients of the hydrogels were studied using modified Franz-Diffusion cells in an acetate buffer with pH 5.5 and temperature 37 degrees C during a period of 48 h, in order to determine the effects of crosslinking ratio, electric field strength, and electrode polarity. The amounts of drug released were analyzed by UV-vis spectrophotometry. The amounts of drug released vary linearly with square root of time. The diffusion coefficients of drug-loaded PVA hydrogels decrease with increasing crosslink ratio. Moreover, the diffusion coefficients of the charged drug in the PVA hydrogels depend critically on the electric field strength between 0 and 5 V as well as on the electrode polarity. Thus, the release rate of sulfosalicylic acid can be altered and controlled precisely through electric field stimulation.     

Development and Characterization of a Novel,Antimicrobial, Sterile Hydrogel Dressing for Burn Wounds: Single‐Step Production with Gamma Irradiation Creates Silver Nanoparticles and Radical Polymerization

Patients with burn wounds are susceptible to wound infection and sepsis. This research introduces a novel burn wound dressing that contains silver nanoparticles (SNPs) to treat infection in a 2‐acrylamido‐2‐methylpropane sulfonic acid sodium salt (AMPS‐Na⁺) hydrogel. Silver nitrate was dissolved in AMPS‐Na⁺ solution and then exposed to gamma irradiation to form SNP‐infused hydrogels. The gamma irradiation results in a cross‐linked polymeric network of sterile hydrogel dressing and a reduction of silver ions to form SNPs infused in the hydrogel in a one‐step process. About 80% of the total silver was released from the hydrogels after 72 h immersion in simulated body fluid solution; therefore, they could be used on wounds for up to 3 days. All the hydrogels were found to be nontoxic to normal human dermal fibroblast cells. The silver‐loaded hydrogels had good inhibitory action against Pseudomonas aeruginosa and methicillin‐resistant Staphylococcus aureus. Results from a pilot study on a porcine burn model showed that the 5‐mM silver hydrogel was efficient at preventing bacterial colonization of wounds, and the results were comparable to the commercially available silver dressings (Acticoat^TM, PolyMem Silver®). These results support its use as a potential burn wound dressing. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3244–3253, 2014     

Effect of Peptide Loading and Surfactant Concentration on the Characteristics of Physically Crosslinked Hydrogel

The purpose of this study was to investigate the effect of varying drug load and concentration of a surfactant (sodium lauryl sulfate [SLS]) on the release characteristics of a model peptide (bovine serum albumin [BSA]), and study the net effects of the swelling properties of the hydrogel matrix [poly(vinyl alcohol) (PVA)]. The PVA hydrogel was prepared by a freeze-thaw process in the absence of a chemical crosslinking agent. The effect of protein loading on drug release was examined at three levels (0.65, 1.3, and 2%), whereas the effect of SLS was studied at four levels (0, 0.07, 0.13, and 0.26%). The baseline time for reaching equilibrium swelling was 48 hr for the hydrogel containing 0.65% BSA, and the equilibrium swelling time decreased significantly as the protein load was increased to 2%. The net effect of increased BSA concentrations resulted in faster BSA dissolution from the hydrogel matrix. The equilibrium-swelling ratio decreased from 21 to 10% when SLS was added to the PVA solution, which resulted in a reduction in the extent of equilibrium swelling; however, the time to reach equilibrium swelling was increased. The investigation provided a mechanistic basis toward the development of a hydrogel formulation by altering the concentration of two fundamental components, i.e., drug and surfactant, within the delivery system.     

Characterisation of the interactive properties of microcrystalline cellulose-carboxymethyl cellulose hydrogels

Combinations of microcrystalline cellulose (MCC) and sodium carboxymethyl cellulose (Na-CMC) are commonly used as stabilising agents and suspending agents in pharmaceutical formulations. This paper is based on a study of the interactions that take place during the process of hydrogel formation, break down, and recovery. Also considered is the binding that occurs between the MCC and the Na-CMC. Avicel RC 591, a processed mixture of MCC and Na-CMC, is one of the more commonly used commercial suspending agents for aqueous compositions. Avicel RC 591 is used as an effective, blended stabilising agent. In this study, the contributions made by each of the components of Avicel RC 591 have been rationalised by monitoring the behaviour of the individual components in Avicel RC 591 suspensions or solutions. The hydrogels that are formed by Avicel RC 591 and by their laboratory formulated equivalent, which is spray dried (MCC+Na-CMC), have been characterised by confocal microscopy scanning electron microscopy and by dynamic light scattering. A 3D network structure that is formed by the MCC, in Avicel RC 591 is visualised. This network is supported by hydrogen bonding and by ionic interactions among and between the MCC, the Na-CMC and water. The strength of the network determines the physical properties of the hydrogel system, as seen in the rheological behaviour.     

Cyclodextrin modified hydrogels of PVP/PEG for sustained drug release

Hydrogels are water swollen networks of polymers and especially hydrogels consisting of poly vinylpyrrolidone/poly ethyleneglycol-dimethacrylate (PVP/PEG-DMA) blends show promising wound care properties. Enhanced functionality of the hydrogels can be achieved by incorporating drugs and other substances that may assist wound healing into the gel matrix. Controlling the release of active compounds from the hydrogels may be possible by carefully modifying the polymer matrix. For this purpose, cyclodextrins (CD) were grafted to the polymer matrix in 4–5 w/w% in an attempt to retard the release of water-soluble drugs. Ibuprofenate (IBU) was chosen as model drug and loaded in IBU/CD ratios of 0.6, 1.2, and 2.5. Vinyl derivatives of α-, β- and γ-CD were produced, added to the prepolymer blend and cured by UV-light. During this curing process the CD derivatives were covalently incorporated into the hydrogel matrix. The modified hydrogels were loaded with ibuprofenate by swelling. The release of the model drug from CD modified hydrogels show that especially covalently bonded β-cyclodextrin can change both the release rate and the release profile of ibuprofen.     

Effect of ethylene glycol dimethacrylate on swelling and on metformin hydrochloride release behavior of chemically crosslinked pH–sensitive acrylic acid–polyvinyl alcohol hydrogel

Background

The present work objective was to prepare and to observe the effect of ethylene glycol dimethacrylate on swelling and on drug release behavior of pH-sensitive acrylic acid–polyvinyl alcohol hydrogel.

Methods

In the present work, pH sensitive acrylic acid–polyvinyl alcohol hydrogels have been prepared by free radical polymerization technique in the presence of benzoyl peroxide as an initiator. Different crosslinker contents were used to observe its effect on swelling and on drug release. Dynamic and equilibrium swelling studies of prepared hydrogels were investigated in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strengths. Hydrogels were evaluated for polymer volume fraction, solvent interaction parameter, molecular weight between crosslinks, number of links per polymer chain, diffusion coefficient, sol–gel fraction and porosity. To demonstrate the release pattern of the drug, zero-order, first-order, higuchi and korsmeyer-peppas models were applied. Quality and consistency of hydrogels was examined by FTIR and surface morphology of hydrogels was examined by SEM.

Results

Decrease in swelling and in drug release was seen by increasing content of ethylene glycol dimethacrylate. A remarkable high swelling was observed at high pH indicating the potential of this hydrogel for delivery of drugs to intestine. By increasing the concentration of ethylene glycol dimethacrylate, porosity decreased. Order of release was observed first order in all cases and the mechanism was non–fickian diffusion. FTIR confirmed the formation of network. SEM results showed the incorporation of drug.

Conclusion

The prepared hydrogels can be suitably used for targeted drug delivery to the intestine.     

Physical characterisation and component release of poly(vinyl alcohol)-tetrahydroxyborate hydrogels and their applicability as potential topical drug delivery systems

Poly(vinyl alcohol)-tetrahydroxyborate (PVA-THB) hydrogels are dilatant formulations with potential for topical wound management. To support this contention, the physical properties, rheological behaviour and component release of candidate formulations were investigated. Oscillatory rheometry and texture profile analysis were used at room temperature and 37 °C. Results showed that it was possible to control the rheological and textural properties by altering component concentration and modifying the type of PVA polymer used. Hydrogels made using PVA grades with higher degrees of hydrolysis displayed favourable characteristics from a wound healing perspective. In vitro release of borate and PVA were assessed in order to evaluate potential clinical dosing of free species originating from the hydrogel structure. Component diffusion was influenced by both concentration and molecular weight, where relevant, with up to 5% free PVA cumulative release observed after 30 min. The results of this study demonstrated the importance of poly(vinyl alcohol) selection for ensuring appropriate gel formation in PVA-THB hydrogels. The benefits of higher degrees of hydrolysis, in particular, included lower excipient release and reduced bioadhesion. The unique physical characteristics of these hydrogels make them an appealing delivery vehicle for chronic and acute wound management purposes.     

Sustained Release of Diltiazem Hydrochloride from Cross-linked Biodegradable IPN Hydrogel Beads of Pectin and Modified Xanthan Gum

Interpenetrating polymer network hydrogel beads of pectin and sodium carboxymethyl xanthan were prepared by ionotropic gelation with Al⁺³ ions and covalent cross-linking with glutaraldehyde for sustained delivery of diltiazem hydrochloride. Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning colorimetry and scanning electron microscopy were used to characterise the hydrogel beads. The swelling of the hydrogel and the release of drug were relatively low in pH 1.2 buffer solutions. However, higher swelling and drug release were observed in pH 6.8 buffer solutions. The carboxyl functional groups of hydrogels undergo ionisation and the osmotic pressure inside the beads increases resulting in higher swelling and drug release in higher pH. The release of drug depends on concentration of polymer, amount and exposure time of cross-linker and drug content in the hydrogel matrices. The present study indicated that the hydrogel beads minimised the drug release in pH 1.2 buffer solutions and to prolong the drug release in pH 6.8 buffer solutions.     

A photo-crosslinked poly(vinyl alcohol) hydrogel growth factor release vehicle for wound healing applications

The objective of this study was to develop and evaluate a hydrogel vehicle for sustained release of growth factors for wound healing applications. Hydrogels were fabricated using ultraviolet photo-crosslinking of acrylamide-functionalized nondegradable poly(vinyl alcohol) (PVA). Protein permeability was initially assessed using trypsin inhibitor (TI), a 21 000 MW model protein drug. TI permeability was altered by changing the solids content of the gel and by adding hydrophilic PVA fillers. As the PVA content increased from 10% to 20%, protein flux decreased, with no TI permeating through 20% PVA hydrogels. Further increase in model drug release was achieved by incorporating hydrophilic PVA fillers into the hydrogel. As filler molecular weight increased, TI flux increased. The mechanism for this is most likely an alteration in protein/gel interactions and transient variations in water content. The percent protein released was also altered by varying protein loading concentration. Release studies conducted using growth factor in vehicles with hydrophilic filler showed sustained release of platelet-derived growth factor (PDGF-β,β) for up to 3 days compared with less than 24 hours in the controls. In vitro bioactivity was demonstrated by doubling of normal human dermal fibroblas numbers when exposed to growth factor-loaded vehicle compared to control. The release vehicle developed in this study uses a rapid and simple fabrication method, and protein release can be tailored by modifying solid content, incorporating biocompatible hydrophilic fillers, and varying protein loading concentration.     

Matrices containing NaCMC and HPMC 2. Swelling and release mechanism study

The aim of the present study is an investigation of the swelling behaviour of matrix systems containing a mixture of hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) with a model soluble drug to find the correlation between the morphological behaviour and the drug release performance. The swelling study was conducted on tablets containing only the drug and the two polymers mixture (MB) and on reference tablets containing each polymer and the same drug, at three different pHs. MB matrices show a similar swelling trend at pH 4.5 and 6.8, while they have different behaviour in acidic fluid. At pH 1 the gel layer formed by NaCMC is characterized by a rigid structure of a partially chemically crosslinked hydrogel while HPMC and MB matrices form a physical not crosslinked gel. At pH 4.5 and 6.8, all the systems show the typical morphological behaviour of a swellable matrix in which the macromolecular chains in the gel network are held together by weak bondings (physical gel). In these buffers, MB systems maintain a constant drug release rate coupling diffusion and erosion mechanism: the gel and infiltrated layers thicknesses are maintained constant and a zero-order release kinetics can be achieved.