(602i) Crosslinking Affects Antibiotic Release from Thiol-Ene Microparticles.

Drug delivery systems, such as microparticles, enhance treatment by improving therapeutic efficacy, reducing toxicity, and enabling new medical therapies. Microparticles made using thiol-ene polymerization are promising for use as local drug delivery systems. Thiol-ene polymerization has advantages such as fast reaction rates, high yields, eco-friendly products, and perfect crosslinking structures, making microparticles made using thiol-ene polymerization suitable for use as drug delivery systems. Crosslinking influences a polymer’s properties; hence, our study investigates the impact of increased crosslinking using pentaerythritol tetra(3-mercaptopropionate) (PETMP) on thiol-ene microparticle drug release behavior.

We increased the mole ratio of our crosslinking agent, PETMP, to the monomer used in the thiol-ene reaction (2-thiol) from 90:10 to 100:0 in two groups: F1 (90:10 alkene: surfactant ratio) and F2 (80:20 alkene: surfactant ratio). Both groups were pre-soaked in 20 and 50 mg/mL of a broad-spectrum antibiotic, doxycycline hyclate. Doxycycline release from the microparticles placed in PBS was measured using UV-vis spectroscopy for five days. Statistical analysis was performed using one-way ANOVA.

Increased crosslinking affected the drug release behavior of all formulations pre-soaked in 20 and 50 mg/mL doxycycline hyclate solution. The F1 group presoaked in 50 mg/mL doxycycline hyclate solution showed an increased amount of drug released only for the PETMP ratio of 0.94 and 0.98, where a 32% and 68% increase was observed, respectively, compared to the 0.90 PETMP control formulation. Other formulations showed lower drug release amounts than the control. In the F2 groups presoaked in 50 mg/mL doxycycline hyclate solution, increasing the PETMP ratio increased the amount of drug released compared to the control formulation of 0.90 PETMP for all the formulations in the group. All formulations in group F1 and F2 presoaked in 20 mg/mL doxycycline showed a decreased amount of drug release than the control formulations, 0.90 PETMP.

Drug release behavior depended on soaking concentration and crosslinking amount, indicating the potential for tunable drug delivery using thiol-ene microparticles in drug delivery applications.