Study of wound dressing structure and hydration/dehydration properties

a b s t r a c tDiabetic foot ulcers (DFUs) are a chronic, non-healing complication of diabetes that lead to high hospital costs and, in extreme cases, to amputation. Diabetic neuropathy, peripheral vascular disease, abnormal cellular and cytokine/chemokine activity are among the main factors that hinder diabetic wound repair. DFUs represent a current and important challenge in the development of novel and efficient wound dressings. In general, an ideal wound dressing should provide a moist wound environment, offer protection from secondary infections, remove wound exudate and promote tissue regeneration. However, no existing dressing fulfills all the requirements associated with DFU treatment and the choice of the correct dressing depends on the wound type and stage, injury extension, patient condition and the tissues involved. Currently, there are different types of commercially available wound dressings that can be used for DFU treatment which differ on their application modes, materials, shape and on the methods employed for production. Dressing materials can include natural, modified and synthetic polymers, as well as their mixtures or combinations, processed in the form of films, foams, hydrocolloids and hydrogels. Moreover, wound dressings may be employed as medicated systems, through the delivery of healing enhancers and therapeutic substances (drugs, growth factors, peptides, stem cells and/or other bioactive substances). This work reviews the state of the art and the most recent advances in the development of wound dressings for DFU treatment. Special emphasis is given to systems employing new polymeric biomaterials, and to the latest and innovative therapeutic strategies and delivery approaches.

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“…This is mostly due to its water absorption and oxygen permeability properties [231,232]. PVP hydrogels can be produced at relatively low cost.…”

Section: Poly(vinyl Pyrrolidone) (Pvp)mentioning

confidence: 99%

Recent advances on the development of wound dressings for diabetic foot ulcer treatment—A review

et al. 2013

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“…The gel percent in the hydrogel was determined from the following equation:

G e l (%) = \frac{W E}{W g} \times 100, (1)

where

W E

and

W g

are dry hydrogel weights after and before extraction, respectively [18]. …”

Section: Methodsmentioning

confidence: 99%

Production of Prednisolone by Pseudomonas oleovorans Cells Incorporated Into PVP/PEO Radiation Crosslinked Hydrogels

El-Hady

El‐Rehim

2004

BioMed Research International

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In order to rise the yield of prednisolone from hydrocortisone, the Pseudomonas oleovorans cells were entrapped into radiation crosslinked poly (vinyl pyrrolidone)/poly(ethylene oxide) (PVP/PEO) hydrogel of different gel contents. The factors affecting the gel content and swelling behavior of the polymeric gel, such as polymer composition, polymer blend concentration, and irradiation doses, were investigated. The formation of gels having a good strength with the ability to retain a desirable amount of water in their three-dimensional network can be achieved by using PVP/PEO copolymer of composition (90 : 10) and concentration of 15% prepared at 20 kGy irradiation dose. At these conditions the prepared hydrogel is considered the most favorable one that gave the highest hydrocortisone bioconversion and prednisolone yield, 81% and 62.8%, respectively. The improvement of prednisolone yield was also achieved by increasing substrate concentration. Maximum hydrocortisone bioconversion (86.44) was obtained at 18 hours by using substrate concentration of 30 mg. Reusability of immobilized Pseudomonas oleovorans entrapped into PVP/PEO copolymer hydrogel was studied. The results indicated that the transformation capacity of hydrocortisone to prednisolone highly increased by the repeated use of copolymer for 4 times. This was accompanied by an increase in prednisolone yield to 89% and the bioconversion of hydrocortisone was 98.8%.

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“…Carrageenan is also successful in controlling discoloration, maintaining texture through shelf life, and providing antibacterial protection by coating on sliced lychee (Plotto, Narciso, Baldwin, & Rattanapanone, 2006), bananas (Bico, Rapaso, Morais, & Morais, 2009), and mangoes (Plotto et al, 2006). The use of blended PVP with agar in hydrogel dressings has also been reported (Lugao et al, 1998). The synthesis of agar-graftpolyvinylpyrrolidone (PVP) and κ-carrageenan-graft-PVP blends by a microwave irradiation method has been reported (Prasad et al, 2006).…”

Section: Carrageenanmentioning

confidence: 99%