Characterisation of drug-release textiles

A variety of test methods are used to characterise drug-releasing textiles however, the main characteristics that are commonly determined are mechanical properties, morphology, degradation, chemical functionality, and of course drug-loading capacity and release kinetics. 

Infrared spectroscopy is used to identify and quantitatively analyse chemical compounds, mixtures, extent of reaction, and molecular stmcture. Various chemical compounds absorb infrared radiation at frequencies corresponding to their own molecular vibrational frequencies. Fourier transform infrared spectra of the textile surfaces is carried out to determine the functional groups and the extent of the reaction of the bioactive groups with the textile. 

The mechanical properties of both fibres and textile stmctures are important to determine the suitability of dmg-releasing textiles in various applications. Tensile strength and extension to break values can be determined using standard tensile testing equipment. These values provide a good indication of the mechanical durability of the textiles before and after treatment with bioactive agents. Kumar and co-workers have reported that the bioactive textiles used in regenerative medical applications 

To determine the antibacterial activity of the treated textile fabrics AATCC Test Method 147 is commonly used. In this method, an agar surface is inoculated by making a parallel streak. The sample is then pressed onto the plate, which is inoculated and incubated at 37 °C and the antibacterial activity is estimated by observing the decrease in growth of the organism from one end of each streak to the other end and from one streak to the next streak and by determining the size of the zone of inhibition. 

The agar diffusion method (Kirby—Bauer) is also sometimes used for the evaluation of antibacterial activity of textiles. This is a relatively quick and easily executed semiquantitative method to determine antibacterial activity of diffusible antimicrobial agents on treated textile material. The bacteria are grown in nutrient broth medium and after appropriate dilution (e.g., lOOx) from the culture, test organisms are swabbed over the surface of agar plates. Ten-millimetre-diameter disks of the test fabric and control fabric are then gently pressed onto the surface of the plate. The plates are then incubated at 37 °C for 18—24 h. The antibacterial activity of the fabrics is demonstrated by the diameter of the zone of inhibition in comparison to the control textile sample. 

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