The Exploration Of A Novel Biodegradable Drug-eluting Biliary Stent:Preliminary Work

OBJECTIVE To explore the degradation,drug release,and mechanical properties of the drug-loaded films made by different ratios of poly(lactic-co-glycolic acid)(PLGA)and different amounts of paclitaxel(PTX)for the subsequent fabrication of a novel biodegradable drug-eluting biliary stent.MATERIALS AND METHOD Different ratios of PLGA(50/50,70/30,80/20)were added to dichloromethane at a ratio of 1:25,and different volumes of PTX(0%,10%,20%,30%)were added to drug-loaded groups.After completely dissolving,the solution was poured evenly into a petri dish and let dry for 48 hours.The PLGA film was removed and cut into small pieces of 10 mm x 10 mm,20 mm x 20 mm,and 10 mm x 50 mm.The actual volume of drug loaded was detected by high performance liquid chromatography.Films were placed in phosphate buffered saline of pH 7.4 in a temperature-controlled shaker.Samples were taken randomly at corresponding time points to test the mechanical tensile strength,weight loss,pH value of the soaking solution,and drug release.The morphology of the films at different time points was observed under a scanning electron microscope.RESULTS The actual volumes of drug loaded matched the theoretical volume,indicating the good drug-loading ability of PLGA.As of the 10 th week of degradation,PLGA 80/20 can still withstand a tensile force of 9.7 N,while PLGA50/50 and 70/30 cracked spontaneously without bearing any force since day 4.At 11 weeks of degradation,the weight loss of PLGA 50/50,70/30,and 80/20 was 95.15%,82.32%,and 16.17%,respectively;and the lowest pH value of the soaking solution was 1.87,1.95,and 6.58,respectively.The rate of drug release of 10%,20%,and30% PTX groups were 3.52–4.48%,1.90–2.26%,and 1.44–2.06%,respectively.Scanning electron microscope showed smooth films;however,after the mechanical strength was lost,cracks could be seen on the surface of the films.CONCLUSION The degradation rate of PLGA can be controlled by adjusting the ratio of lactic acid and glycolic acid.Overall,the degradation rate of PLGA 50/50 and70/30 is significantly faster than 80/20.PLGA is proved a good drug carrier that PTX can be securely attached to,and these drug-loaded films are able to slowly release PTX as itself degrades over time.