Cadexomer-iodine in the treatment of venous leg ulcers: what is the evidence?

Absorptive supramolecular elastomer wound dressing based on polydimethylsiloxane–(polyethylene glycol)–polydimethylsiloxane copolymer: preparation and characterization

The introducing of polyethylene glycol block could effectively enhance the hydrophilicity, water-absorbing rate, ability of cohesion and water vapor permeating rate of ESESi film, and help to promoting the wound healing processing.

A critical review of modern and emerging absorbent dressings used to treat exuding wounds

Wound management has progressed significantly over the last five decades. This emanates from a greater understanding of wound healing, technological progression and improved clinical and scientific research. There are currently a plethora of absorbent dressings on the wound care market which claim to have the ability to manage exudates whilst encouraging healing. However, it is becoming clear, from analysing randomised controlled trials, that some of these absorbent dressings are not meeting their expectations when applied in a clinical setting. Many clinicians now feel that there should be more focus, not only on a dressing's ability to manage exudate efficiently, but on a dressing's ability to proactively encourage healing and thus exudate reduction will ensue. This paper proposes to critically review modern and emerging absorbent wound care dressings used to manage exuding wounds and discuses some advances in this area.

Influence of various treatments including povidone-iodine and healing stimulatory reagents in a rabbit ear wound model

Selecting an appropriate treatment for a given case of skin wound is crucial for inducing optimal healing. We used an animal model developed from normal rabbit ears in order to assess the efficacy of treatments for skin wounds with or without a wet dressing, anti microbial reagent or topical wound-stimulatory reagents. The degree of healing in each group was evaluated and compared using four histological parameters: (i) degree of reepithelialisation, (ii) amount of granulation tissue formation, and (iii) the number of capillary lumens and (iv) fibroblasts in the granulation tissue. Treatment using wet dressings resulted in an increase in capillary number compared with the open dry wound. Although the retention of povidone-iodine (PI) in wound tissue after application significantly inhibited reepithelialisation (P < 0.05), rinsing PI off with saline was comparable in effect to using only a wet dressing. The three topical reagents, namely, basic fibroblast growth factor, prostaglandin E1 and dibutyryl cyclic adenosine monophosphate, significantly improved reepithelialisation (P < 0.05). In conclusion, wounds should be kept hydrated by applying topical reagents. If there are any signs of bacterial infection, PI can be applied and rinsed later with saline in order to minimise its cytotoxic effects.

Critical evaluation of cadexomer-iodine ointment and povidone-iodine sugar ointment

Topical iodine forms are used for infected and necrotic pressure ulcers. Despite antimicrobial advantages several potential disadvantages were observed with controversial results. To clarify the controversy, the reactivity of povidone-iodine (PI) sugar ointment and cadexomer-iodine (CI) ointment toward biological components was investigated. L-Tyrosine as a component of proteins and egg lecithin as a component of lipid membranes were reacted with forms of iodine. Furthermore, water absorption abilities of ointments were investigated. The reactions of PI sugar ointment and CI ointment with L-tyrosine were reversely dependent on iodine concentrations. CI ointment reacted with lecithin in an iodine concentration dependent manner, while PI sugar ointment reacted with lecithin in an iodine concentration independent steady manner. However, at the clinically relevant iodine concentration (0.1, w/v%) PI sugar ointment reacted efficiently with L-tyrosine and less efficiently with lecithin, while CI ointment reacted efficiently with lecithin and less efficiently with L-tyrosine. Water absorption rate constant was 29.9 mg/cm(2)/min(0.5) for PI sugar ointment and 15.3 for CI ointment. Water absorption capacity per weight over 24 h was 26% forPI sugar ointment and 76% for CI ointment [corrected]. These results suggest that PI sugar ointment and CI ointment have different characteristics for iodine reactivity and water absorption.

Mixture of sugar and povidone-iodine stimulates healing of MRSA-infected skin ulcers on db/db mice

The topical application of a mixture of sugar and povidone-iodine (PI) has been reported to accelerate the healing of cutaneous wounds and ulcers by promoting reepithelialization and granulation tissue formation, as well as by having an anti-microbial effect. In order to clarify the efficacy of a 70% sugar and 3% PI paste (U-PASTA(SP) on infectious skin ulcers, we made a bacterial infection model using methicillin-resistant Staphylococcus aureus (MRSA) on the skin of diabetic db/db mice, and investigated the effect of the paste on the healing process of wounds. Full-thickness wounds were made on the backs of female diabetic mice, (C57BL/ksJ db/db) and inoculated with S. aureus. SP was applied to the closed wounds for 8 days. The degree of repair was evaluated using three histological parameters: The degree of reepithelialization was given a percentage value of 0-100%; the amount of granulation tissue was quantified by measuring the area of granulation (mm(2)); and the number of capillary lumens in the granulation tissue was counted in the complete wound cross-section at 100x magnification. In addition, the colony-forming units (CFU) of MRSA on the wounds were counted. Continuous MRSA infection in the wounds of db/db mice was demonstrated with macroscopic and histopathological images. Wounding and infection caused by MRSA on the back of the diabetic mice significantly induced delayed reepithelialization, granulation tissue formation with inflammatory cell infiltrate and increased CFU on wounds (P < 0.01, respectively) compared to those of the MRSA-infected normal mice. Application of SP significantly accelerated reepithelialization (P < 0.01) and decreased CFU (P < 0.05) of the ulcers in the MRSA-infected wounds, compared to the non-treated group. Histopathological evaluation and CFU on this animal model revealed no significant difference between Methicilin-sensitive Staphylococcus aureus and MRSA infection. These results indicate that wounding on db/db mice provides a useful animal model of bacterial skin infections, and that SP is an effective topical agent for the treatment of diabetic skin ulcers.

Mixture of sugar and povidone--iodine stimulates wound healing by activating keratinocytes and fibroblast functions

The topical application of a mixture of sugar and povidone--iodine (PI) has been reported to accelerate the healing of cutaneous wounds and ulcers by promoting re-epithelialization and granulation tissue formation as well as having an anti-microbial effect. To clarify the mechanisms accounting for the efficacy of a 70% sugar and 3% PI paste (U-PASTAtrade mark) (SP), various keratinocytes and fibroblasts functions, including proliferation, collagen synthesis, integrin expression, and cytokine and proteinase secretions in the presence of SP were investigated. Cultured human keratinocytes and fibroblasts were treated with various concentrations of SP, SU and PI. The secretion of urokinase-type plasminogen activator (u-PA), transforming growth factor (TGF)-alpha and interleukin-1alpha from keratinocytes, was detected by ELISA. Collagen synthesis of fibroblasts was examined by means of detecting proline uptake. Furthermore, integrin expressions of these cells were analyzed using a flow cytometer. SP and PI increased intra-cellular u-PA of keratinocytes and stimulated the secretion of u-PA and TGF-alpha. Sugar accelerated the extra-cellular u-PA level only. Both SP and sugar increased the collagen synthesis of fibroblasts. SP and PI also remarkably induced the expressions of extra-cellular matrix receptor integrins, alpha1, alpha2, alpha3, alpha4, alpha5 and beta1, on the surface of keratinocytes and fibroblasts. SP, the mixture of sugar and PI, is likely to act on wounds not only as an antibiotic agent, but also as a modulator for keratinocytes and fibroblasts.