Tetracycline Hydrate and Gentamicine Sulfate Containing Carboxymethylated Cotton Fabric Suitable for Moist Wound Healing Dressings: Properties and Evaluation

Abstract

In order to prepare moist healing wound dressings based on cotton gauze fabrics, the latter are carboxymethylated to carboxyl contents of 72, 170, and 220meq/100g. In contrast to the other two samples, the first sample showed no gelling in phosphate buffered saline (PBS) at 37°C. The carboxyl contents of the gelling samples are made in Ca/Na forms in 3% degree of neutralization (% DN), 10/90, 20/80, and 30/70), while that of the first is left in its Na form. To acquire them antibacterial activity, all samples are padded in 20/80 ethanol/water containing different concentrations (25—1000 mg/L) of either tetracycline hydrate (TCH, in presence of 50g/L polyvinyl pyrrolidone) or gentamicine sulfate and air dried. The samples are characterized by determining their contents of antibiotics, swelling, and shrinkage. Evaluation is achieved by assessing in vitro release of antibiotics in PBS at 37°C and antibacterial activity, expressed as inhibition clear zone (ICZ), towards Staphylococcus aureus (G +ve) and Pseudomonas aeruginosa (G -ve). It is found, for a given set of conditions, that: (a) TCH or gentamicine (G) content increased by increasing both of its concentration and carboxyl content, but decreased by increasing the% DN by Ca, (b) swelling and shrinkage slightly (or remarkably) decreased by increasing the content of TCH (or% DN by Ca), but noticeably increased by increasing the carboxyl content, (c) in vitro release is the highest on the first day, then decreased on prolonging the time up to the third day, and (d) in vitro release and ICZ (towards G+ve and G—ve bacteria) increased by increasing antibiotic and carboxyl contents, but decreased by increasing% DN by Ca. Properties of the TCH or G containing Ca/Na carboxymethylated samples make them suitable candidates as antibacterial moist wound healing dressings.