Textile dressing for drug delivery – ascorbic acid on cotton fabric

Abstract

Chronic venous leg ulcers are characterised by pain, infection, poor healing and high rates of re-occurrence, resulting in high healthcare costs and often a reduced quality of life for the patient. Common treatments include prescription of one or a combination of oral drugs, topically applied drugs, dressings and compression. The oral drug treatment for pain and infection can cause adverse side effects such as gastro-intestinal upsets, which result in a decrease in patient compliance. High levels of exudate require dressings to be changed frequently, which can re-irritate and weaken the wound. The use of a transdermal dressing reduces these side effects, hence the objectives of the study were to develop a method to apply ascorbic acid to a standard cotton fabric in a form that is stable for a period of time; to describe physical properties of the standard fabric; and to examine the presence of the ascorbic acid on/in the fibre, its concentration, and form. A plain woven cotton fabric meeting standard characteristics was washed and dried following a standard pre-treatment method and specimens were randomised for treatment and subsequent testing. Specimens were treated with water-based liposomes containing either 150g/L or 200g/L ascorbic acid. Standard textile test methods were used or adapted where appropriate throughout this work. The physical properties, mass per unit area, thickness, and permeability to water vapour and air were measured before and after treatment. Sett was calculated after pre-treatment but prior to liposome treatment. The mass and degradation of ascorbic acid over time was measured using Ballentine’s assay of ascorbic acid. The form of ascorbic acid was analysed using FTIR spectroscopy and XRPD, and the presence on the fibre surface was examined using SEM. The water-based liposomes provided an effective means of applying ascorbic acid to the plain woven cotton fabric and prevented significant degradation of the ascorbic acid over a one month period. The physical properties of the fabric affected by treatment were mass per unit area and permeability to air, while no differences in thickness and permeability to water vapour were identified. Mass per unit area differed between 150g/L and 200g/L treated and non-treated specimens. Permeability to air differed only between treated and non-treated not between treatment concentrations. FTIR spectroscopy and XRPD were valuable techniques to determine that the ascorbic acid on the fabric was crystalline. SEM at high magnification (1000x and 5000x) provided images of crystal-like structures on the fibre that were assumed to be ascorbic acid. The current work reports a method of successfully applying ascorbic acid to a standard cotton fabric which was intended to be used to treat chronic venous ulcers.