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.     

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.     

Effect of sodium carboxymethylcellulose and fucidic acid on the gel characterization of polyvinylalcohol-based wound dressing

The purpose of this study was to investigate the effect of sodium carboxymethylcellulose (Na-CMC) and fucidic acid on the gel characterization for the development of sodium fucidate-loaded wound dressing. The cross-linked hydrogel films were prepared with polyvinyl alcohol (PVA) and sodium carboxymethylcellulose (Na-CMC) using the freeze-thawing method. Their gel properties such as gel fraction, swelling, water vapor transmission test, morphology, tensile strength and thermal property were investigated. In vitro protein adsorption test and release were performed. Na-CMC decreased the gel fraction and tensile strength of the hydrogels, but increased the swelling ability, water vapor transmission rate, elasticity and porosity of hydrogels. Thus, the wound dressing developed with PVA and Na-CMC was more swellable, flexible and elastic than that with only PVA because of its cross-linking interaction with PVA. However, the drug had a negative effect on the gel properties of hydrogels but there were no significant differences. In particular, the hydrogel composed of 2.5% PVA, 1.125% Na-CMC and 0.2% drug might give an adequate level of moisture and build up the exudates on the wound area. Thus, this sodium fucidate-loaded hydrogel could be a potential candidate for wound dressing with excellent forming.     

Neomycin-loaded poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA)/polyvinyl alcohol (PVA) ion exchange nanofibers for wound dressing materials

In this study, poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA) blended with polyvinyl alcohol (PVA) was electrospun and then subjected to thermal crosslinking to produce PSSA-MA/PVA ion exchange nanofiber mats. The cationic drug neomycin (0.001, 0.01, and 0.1%, w/v) was loaded onto the cationic exchange fibers. The amount of neomycin loaded and released and the cytotoxicity of the fiber mats were analyzed. In vivo wound healing tests were also performed in Wistar rats. The results indicated that the diameters of the fibers were on the nanoscale (250 ± 21 nm). The ion exchange capacity (IEC) value and the percentage of water uptake were 2.19 ± 0.1 mequiv./g-dry fibers and 268 ± 15%, respectively. The loading capacity was increased upon increasing the neomycin concentration. An initial concentration of 0.1% (w/v) neomycin (F3) showed the highest loading capacity (65.7 mg/g-dry fibers). The neomycin-loaded nanofiber mats demonstrated satisfactory antibacterial activity against both Gram-positive and Gram-negative bacteria, and an in vivo wound healing test revealed that these mats performed better than gauze and blank nanofiber mats in decreasing acute wound size during the first week after tissue damage. In conclusion, the antibacterial neomycin-loaded PSSA-MA/PVA cationic exchange nanofiber mats have the potential for use as wound dressing materials.     

Development of a novel antimicrobial seaweed extract-based hydrogel wound dressing

The objective of this study was to develop a novel antimicrobial seaweed wound dressing. The seaweed extract was active against nine clinically-relevant wound pathogens. A hydrogel formulation was prepared using polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), followed by addition of 1% seaweed extract. The antimicrobial properties of the novel dressing were tested using agar diffusion assays, with release-profiles examined using gel leaching and gel transfer assays. The dressing was found to be effective against the same microbial strains as the seaweed extract, with similar efficacy to the commonly used silver-based dressing, Acticoat^®. Antimicrobial release-profile assays revealed that the dressing was effective in inhibiting 70–90% of the bacterial population within the first 30 min, followed by a long, sustained released up to 97 h, without leaving a residue following five subsequent transfers of the dressing. Antimicrobial activity was stable for up to 6 months of storage at 4 °C, but activity was reduced slightly after 15 weeks. Following autoclave sterilization, the dressing displayed a slower release profile compared to a non-autoclaved counterpart. Hence, the seaweed dressing may have commercial applications, potentially competing with silver-based dressings at a lower cost per-application. This is the first report of development of a seaweed-based antimicrobial dressing.     

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。     

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.     

Controlled Release of Chitosan and Sericin from the Microspheres-Embedded Wound Dressing for the Prolonged Anti-microbial and Wound Healing Efficacy

One approach in wound dressing development is to incorporate active molecules or drugs in the dressing. In order to reduce the frequency of dressing changes as well as to prolong wound healing efficacy, wound dressings that can sustain the release of the active molecules should be developed. In our previous work, we developed chitosan/sericin (CH/SS) microspheres that released sericin in a controlled rate. However, the difficulty of applying the microspheres that easily diffuse and quickly degrade onto the wound was its limitations. In this study, we aimed to develop wound dressing materials which are easier to apply and to provide extended release of sericin. Different amounts of CH/SS microspheres were embedded into various compositions of polyvinyl alcohol/gelatin (PVA/G) scaffolds and fabricated using freeze-drying and glutaraldehyde crosslinking techniques. The obtained CH/SS microspheres-embedded scaffolds with appropriate design and formulation were introduced as a wound dressing material. Sericin was released from the microspheres and the scaffolds in a sustained manner. Furthermore, an optimized formation of the microspheres-embedded scaffolds (2PVA2G+2CHSS) was shown to possess an effective antimicrobial activity against both gram-positive and gram-negative bacteria. These microspheres-embedded scaffolds were not toxic to L929 mouse fibroblast cells, and they did not irritate the tissue when applied to the wound. Finally, probably by the sustained release of sericin, these microspheres-embedded scaffolds could promote wound healing as well as or slightly better than a clinically used wound dressing (Allevyn®) in a mouse model. The antimicrobial CH/SS microspheres-embedded PVA/G scaffolds with sustained release of sericin would appear to be a promising candidate for wound dressing application.     

Design and characterization of mucoadhesive buccal patches containing cetylpyridinium chloride

Mucoadhesive patches for delivery of cetylpyridinium chloride (CPC) were prepared using polyvinyl alcohol (PVA), hydroxyethyl cellulose (HEC) and chitosan. Swelling and bioadhesive characteristics were determined for both plain and medicated patches. The results showed a remarkable increase in radial swelling (S(D)) after addition of the water-soluble drug (CPC) to the plain formulae. A decrease in the residence time was observed for PVA and chitosan-containing formulae. Higher drug release was obtained from PVA patches compared to HEC ones, while both are non-ionic polymers. A considerable drop in release was observed for chitosan formulae after the addition of water-soluble additives, polyvinyl pyrrolidone (PVP) and gelatin. Ageing was done on PVA formulae; the results showed there was no influence on the chemical stability of CPC, as reflected from the drug content data. Physical characteristics of the studied patches showed an increase in the residence time with storage accompanied with a decrease in drug release. This may be due to changes in the crystal habit of the drug as well as to slight agglomeration of the polymer particles.     

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.     

A novel electrospun membrane based on moxifloxacin hydrochloride/poly(vinyl alcohol)/sodium alginate for antibacterial wound dressings in practical application

This study reports on the performance of sodium alginate (SA)/poly(vinyl alcohol) (PVA)/moxifloxacin hydrochloride (MH) nanofibrous membranes (NFM) capable of providing antibacterial agent delivery for wound-dressing applications. The aim of this work was to prepare antibacterial NFM with good permeability properties by employing PVA and SA as carriers. A group of 12% PVA/2% SA solutions blended in various ratios (8:2, 7:3, 6:4, 5:5 and 4:6, v/v) and containing 0.5, 1, 2 or 4 wt% MH were studied for electrospinning into nanoscale fibermats. The optimum ratio found to form smooth fibers with uniform fibrous features was 6:4. The drug release behavior of the electrospun, the antibacterial effects on Pseudomonas aeruginosa and Staphylococcus aureus and the animal wound dressing capabilities were also investigated. As much as 80% of the MH was released from the electrospun after 10?h of incubation at 37?°C. In addition, the NFM with 0.5 MH exhibited less activity, whereas those with higher concentrations of MH exhibited greater antibacterial effect. Furthermore, the MH-loaded electrospun accelerated the rate of wound dressing compared to other groups. The results of the in vitro and in vivo experiments suggest that MH/PVA/SA nanofibers might be an interesting bioactive wound dressing for clinical applications.     

Physical solid-state properties and dissolution of sustained-release matrices of polyvinylacetate.

Solid-state compatibility and in vitro dissolution of direct-compressed sustained-release matrices of polyvinylacetate (PVAc) and polyvinylpyrrolidone (PVP) containing ibuprofen as a model drug were studied. Polyvinylalcohol (PVA) was used as an alternative water-soluble polymer to PVP. Differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) were used for characterizing solid-state polymer-polymer and drug-polymer interactions. The mechanical treatment for preparing physical mixtures of polyvinyl polymers and the drug (i.e. simple blending or stressed cogrinding) was shown not to affect the physical state of the drug and the polymers. With the drug-polymer mixtures the endothermic effect due to drug melting was always evident, but a considerable modification of the melting point of the drug in physical binary mixtures (drug:PVP) was observed, suggesting some interaction between the two. On the other hand, the lack of a significant shift of the melting endothermic peak of the drug in physical tertiary drug-polymer mixtures revealed no evidence of solid-state interaction between the drug and the present polymers. Sustained-release dissolution profiles were achieved from the direct-compressed matrices made from powder mixtures of the drug and PVAc combined with PVP, and the proportion of PVAc in the mixture clearly altered the drug release profiles in vitro. The drug release from the present matrix systems is controlled by both diffusion of the drug through the hydrate matrix and the erosion of the matrix itself.     

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.     

Effects of formulation and process variables on the release of a weakly basic drug from single unit extended release formulations.

A new commercially available extended release matrix material, Kollidon SR, composed of polyvinylacetate (PVA) and polyvinylpyrrolidone (PVP), was evaluated with respect to its ability to modulate the in vitro release of the weakly basic drug ZK 811 752. The effect of different formulation and process parameters on the release kinetics of ZK 811 752 from PVA/PVP based matrix tablets was investigated as a function of the (i) nature of excipient added to the drug-polymer mixtures, (ii) method of manufacturing (direct compression versus wet granulation), and (iii) effect of a post-compression curing step. ZK 811 752 containing extended release matrix tablets were successfully prepared by using Kollidon SR. The drug release from the matrix tablets increased by the addition of excipients such as maize starch, lactose and calcium phosphate. Addition of the highly swellable maize starch and the water-soluble lactose accelerated the drug release in a more pronounced manner compared to the water-insoluble calcium phosphate. Compound release from matrix tablets prepared by wet granulation was faster compared to the drug release from tablets prepared by direct compression. Post compression curing did not influence the drug release rate from drug-lactose-Kollidon SR formulations. Stability studies demonstrated no degradation of the drug substance and reproducible drug release patterns for matrix tablets stored at 25 degrees C/60% RH and 30 degrees C/70% RH for up to 6 months.     

Preparation and properties of a pH sensitive carrier based on three kinds of polymer blend to control the release of 5-amino salicylic acid

Abstract

Context: High concentration of 5-amino salicylic acid (5-ASA) in the distal ileum and colon is necessary for the treatment of inflammatory bowel disease (IBD). The control of small molecules, drugs, released from a polymeric matrix remains a great challenge.

Objective: To study the preparation and properties of a pH-sensitive carrier for targeting delivery of 5-ASA.

Materials and methods: The carrier was prepared by ternary blends method based on polyvinyl alcohol (PVA), sodium alginate (SA) and polylactic acid. It was characterized by infrared spectrometry and scanning electronic microscopy. The adsorption and release of 5-ASA in different pH media were investigated.

Results: We found out the best ratio of the materials for synthetic carrier. The vector exhibited good performance by the controlled release of the target drug experiment. The adsorption capacity of the carrier for 5-ASA was 70.34% in phosphate buffer saline at pH 1.00, and the release rate was 100.49% in phosphate buffer solution at pH 6.80.

Discussion and conclusion: PVA is vector backbone of the carrier, and SA plays key role in its pH performance. It is a promising material to effectively deliver 5-ASA to the specific sites of IBD.     

Mucoadhesive patches of Salbutamol sulphate for unidirectional buccal drug delivery: development and evaluation

Mucoadhesive buccal patches of Salbutamol Sulphate were prepared using five different polymers (polyvinylpyrrolidone [PVP]), polyvinyl alcohol [PVA], water soluble chitosan [CH(WS)], acid soluble chitosan [CH(AS)], hydroxypropyl methyl cellulose [HPMC])in various proportions and combinations (CH(WS)/PVP/HPMC, CH(WS)/PVA/HPMC, CH(AS)/PVP/HPMC, and CH(AS)/PVA/HPMC). A 3(2) full factorial design was used to design the experiments. A total of 72 patches were prepared. Thickness of the patches ranged between 0.3±0.003 and 0.6±0.009 mm. Mass of the patches were in the range of 68.12±4.6 to 95.02±7.2 mg. Patches showed increased mass whenever PEG -400 was used as plasticizer. The surface pH of patches were acidic to neutral (pH 4-pH 7). Patches showed satisfactory drug loading efficiency (85%to 97%). Eight formulations(C9, C18, C27, C36, D9, D18, D27, and D36)-which showed high folding endurance- were selected for further characterization. Patches with PEG -400 showed higher swelling index when compared to PG. The residence time of the patches ranged between 115 min and 120 min. Formulation C18 showed the maximum in vitro drug release of 101.4 % over a period of 120 min. Formulations D36 and C36 were best fitted to Higuchi model. The remaining formulations were best fitted to the Korsmeyer-Peppas model. Drug permeation was fast and showed the similar profile as that of the in vitro drug release. Patches were stable, during and at the end of the accelerated stability study.     

Cerium oxide nanoparticle-loaded polyvinyl alcohol nanogels delivery for wound healing care systems on surgery

This study was designed to establish the composition of wound bandages based on Cerium nanoparticle (CeNP)-loaded polyvinyl alcohol (PVA) nanogels. The CeNP nanogel (Ce-nGel) was fabricated by the fructose-mediated reduction of Cerium oxide solutions within the PVA matrix. The influences of different experimental limitations on PVA nanogel formations were examined. The nanogel particle sizes were evaluated by transmission electron microscopy and determined to range from ∼10 to 50 nm. Additionally, glycerol was added to the Ce-nGels, and the resulting compositions (Ce-nGel-Glu) were coated on cotton fabrics to generate the wound bandaging composite. The cumulative drug release profile of the Cerium from the bandage was found to be ∼38% of the total loading after two days. Additionally, antibacterial efficacy was developed for Gam positive and negative microorganisms. Moreover, we examined in vivo healing of skin wounds formed in mouse models over 24 days. In contrast to the untreated wounds, rapid healing was perceived in the Ce-nGel-Glu-treated wound with less damage. These findings indicate that Ce-nGel-Glu-based bandaging materials could be a potential candidate for wound healing applications in the future.     

Development of Meloxicam-Loaded Electrospun Polyvinyl Alcohol Mats as a Transdermal Therapeutic Agent

This study reports on the use of electrospun polyvinyl alcohol (PVA) nanofiber mats loaded with meloxicam (MX) as a transdermal drug delivery system. The amounts of MX loaded in the base PVA solution (10% w/v solution) were 2.5, 5, 10 and 20% weight, based on the dry weight of PVA (% wt). The average diameters of these fibers ranged from 121–185 nm. In all concentrations of MX loaded in spun PVA fiber mats, an amorphous nanodispersion of MX with PVA was obtained. Both the degree of swelling and the weight loss of the electrospun PVA mats were greater than those of the as-cast PVA films. The tensile strength of the as-spun fiber mats was lower than that of the as-cast PVA films, but the strain at the maximum of the as-spun fiber mats was about six times higher than that of the as-cast PVA films. The skin permeation flux of the MX permeated from MX-loaded as-spun PVA were significantly higher than from MX-loaded as-cast PVA films, and increased when the MX content in both MX-loaded as-spun PVA and MX-loaded as-cast PVA films was increased. Our research suggests a potential use for MX-loaded electrospun PVA mats as a transdermal drug delivery system.     

PVP magnetic nanospheres: biocompatibility, in vitro and in vivo bleomycin release

PURPOSE: To synthesize and characterize a magnetic micromolecular delivery system based on PVP hydrogel with polyvinyl alcohol (PVA) as the crosslinker. METHODS: The microparticles were successfully prepared using 25 kGy Co-60 gamma-ray irradiation and characterized. Biocompatibility, in vitro and in vivo drug release tests were carried out. RESULTS AND DISCUSSION: Bleomycin was quantitatively released with in slightly over 8 h (hours) from the nanospheres containing 1mg bleomycin while the time was longer for those containing 5 mg. On the other hand free bleomycin quantitatively passed through the dialysis baffle with in only 3.5 h. For both 5 and 1 mg of bound bleomycin, it took up to 2 h to reach peak concentration compared to 30 min for the free drug. CONCLUSION: The PVP hydrogel magnetic nanospheres exhibited passive drug release that could be exploited to enhance therapeutic efficacy. The present results indicate that PVP hydrogel based magnetic nanospheres have potential as drug carriers in magnetic guided chemotherapeutic drug delivery.     

Fabrication and properties of capsicum extract-loaded PVA and CA nanofiber patches

The aim of this study was to prepare, characterize and evaluate electrospun polyvinyl alcohol (PVA) and cellulose acetate (CA) nanofibers loaded with capsicum extract (CE) for use in topical skin treatments. CE, 0.5, 1 or 2 wt %, was loaded into PVA and CA electrospun fiber mats. Various properties of the CE-loaded fiber mats as well as release and skin permeation were investigated. The average diameters of these fibers ranged from 251–368?nm. The release rate of capsaicin from CE-loaded as-spun PVA was faster than that of the CA fiber mats and increased as the CE content in CE-loaded as-spun PVA and CA increased. The release kinetics of the CA and PVA fibers followed the Higuchi equation. The percentages of CE that permeated the shed snake skin with PVA and CA fiber mats containing 2 wt % CE after 24?h were 60% and 20%, respectively. The results suggest a potential use of PVA and CA nanofibers being used to control skin permeation of capsicum extract. Our research suggests the potential application of CE-loaded PVA electrospun mats as transdermal drug delivery systems.