Investigation of antibiotic release from amoxicillin- and clindamycin-impregnated silk and Vicryl suture materials: an in vitro study

Abstract Background Systemic antibiotic administration requires repeated dosing to maintain therapeutic plasma concentrations. Controlled drug delivery systems reduce the need for continuous systemic antibiotic use by ensuring that the drug is released at the target site, at an effective dose, and for a specific period of time. In this study, amoxicillin and clindamycin were loaded onto silk and Vicryl sutures, which were surface-activated via non-thermal atmospheric plasma. The antibiotic binding capacities and controlled release profiles of these systems were subsequently evaluated. Methods Suture surfaces were modified using atmospheric plasma to enhance adhesion properties. Amoxicillin and clindamycin were loaded onto silk and Vicryl sutures via glutaraldehyde or chitosan cross-linkers to form eight experimental groups. Each experiment was conducted in triplicate. Samples were incubated in phosphate-buffered saline (PBS), and antibiotic release was quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) at 6, 12, 24, and 36 h. Results In vitro experiments revealed a clear influence of both the suture material and the type of cross-linking agent on antibiotic release, and this effect also depended on the antibiotic used (p < 0.001). Silk sutures treated with glutaraldehyde and loaded with clindamycin exhibited the highest release concentration (591.6 ng/mL), followed by the silk–chitosan–clindamycin group (190.21 ng/mL). Conversely, the lowest release was observed in the silk–glutaraldehyde–amoxicillin group (2.58 ng/mL). The comparative evaluation indicated that silk sutures released more antibiotic than Vicryl, glutaraldehyde provided higher release than chitosan, and clindamycin showed markedly greater release than amoxicillin (p < 0.001). Conclusion Surface modification with atmospheric plasma is an effective strategy to enhance the functional characteristics of antibiotic-releasing sutures. This study demonstrates that modified silk and Vicryl materials can achieve site-specific and time-regulated antibiotic delivery. Notably, the silk–glutaraldehyde–clindamycin formulation exhibited the highest release levels and the most robust antibacterial response. These findings suggest that antibiotic-loaded sutures serve as a safe and practical alternative for preventing surgical site infections, potentially reducing reliance on systemic antibiotics. Ultimately, this approach supports the development of next-generation biomaterials designed to mitigate antibiotic resistance and optimize local infection control.