Moist Wound Dressing Fabrications: Carboxymethylation of Antibacterial Cotton Gauze

Cotton gauze wound dressing materials were carboxymethylated in order to maintain moist conditions by increasing the carboxyl contents on their cellulose moieties. Also, to improve their antibacterial efficacy, two synergistic drugs were treated after carboxymethylation. Carboxymethylation of the fabrics was carried out using different concentrations of sodium hydroxide/mono chloro acetic acid (NaOH/MCA) to increase the carboxyl contents (85, 173, 246 mmol/100g). To acquire moist conditions of the fabrics, the carboxyl contents of the gelling samples were made in Ca/Na forms (Na ions was replaced by Ca ions) in three different forms of degree of neutralization (10/90, 20/80, and 30/70). The first non-gelling sample (85 mmol/100g) was left in its Na form to differentiate its chemical and biological properties from the other two samples. In order to fabricate the carboxymethylated (CM) cotton with antibacterial drugs, all the samples were padded in different concentrations (100, 500 and 1000 mg/L) of two synergistic drugs: ofloxacin and ornidazole. These samples were considered as carboxymethylated antimicrobial dressings (CM-AMD). The impact of antibacterial drug content on swelling, gelling, and shrinkage was determined along with the antibacterial activity. Both qualitative and quantitative antibacterial activity was measured for CM-AMD samples. Among the three samples, the first sample (85 mmol/100g) showed no gelling in phosphate buffered saline (PBS), whereas the other two samples (173 and 246 mmol/100g) showed gelling visually. In the present research, it was observed that swelling and shrinkage slightly decreased by increasing the concentrations of antibacterial drugs; and increased by increasing the carboxyl content. The antibacterial activity of CM-AMD when tested qualitatively showed that, the inhibition clear zone (ICZ) increased by increasing drug concentrations and carboxyl contents; but decreased by increasing the degree of neutralization. Quantitative bacterial reduction testing showed 100 % reduction of the test organisms (Staphylococcus aureus and Peptostreptococcus sp) The study concludes that carboxymethylated cotton gauzy fabrics containing more carboxyl contents (≥ 246 mmol/100g) with less degree of neutralization (10 %) treated with synergistic antibacterial drugs could be suitable for fabricating antibacterial wound dressing materials.