Electrospun poly(L-lactide) membranes containing a single drug or multiple drug system for antimicrobial wound dressings

Micro- and nanofibrous electrospun poly(L-lactide) (PLA) and PLA/poly(ethylene glycol) (PEG) membranes containing diclofenac sodium (DS), lidocaine hydrochloride (LHC), benzalkonium chloride (BC), or combinations thereof (DS/LHC and DS/LHC/BC) have been developed. The addition of low molecular weight organic salts to the spinning PLA and PLA/PEG solutions results in increased conductivity and contributes to the preparation of membranes composed of fibers that are well-aligned with the collector rotation direction. The water contact angle values of the PLA and PLA/PEG membranes are characteristic of hydrophobic surfaces. The incorporation of LHC in the fibers does not lead to membrane hydrophilization. In contrast to LHC, other drugs or combinations thereof have led to the preparation of hydrophilic fibrous materials. The hydrophilization is due to the presence of DS or BC fragments or functional groups on the fibrous membrane surfaces as verified by X-ray photoelectron spectroscopy (XPS). As evidenced by the differential scanning calorimetric study and X-ray diffraction analysis data, the drugs incorporated in the fibers are in the amorphous state. The release profiles of DS, LHC, and BC from the PLA/drug and PLA/PEG/drug fibrous membranes depend on the drug nature and, in the case of BC, on the composition of the polymer scaffold as well. The release of DS and LHC from the PLA/DS/LHC and PLA/PEG/DS/LHC membranes is slower compared to that of the single drug-loaded membranes. This phenomenon has been attributed to an ionic interaction between the two drugs. Microbiological studies have demonstrated that the PLA/DS, PLA/BC, PLA/DS/LHC, and PLA/DS/LHC/BC membranes exhibit antibacterial activity against Staphylococcus aureus.