Synthesis and Characterization of Acrylic Pressure-Sensitive Adhesive for Ibuprofen Release in Transdermal Drug Systems

Pressure-Sensitive Adhesives (PSAs) are promising for transdermal drug delivery, enabling controlled drug release and enhanced therapeutic efficacy. In this study, acrylate-based PSAs were synthesized via seeded semi-batch emulsion polymerization using two types of latex and functional monomers (EA, BA, ۲-EHA, AA, HEMA, VAc) in varying ratios. Ibuprofen (IBU) was incorporated to evaluate controlled-release performance. The PSAs were comprehensively characterized for physicochemical, mechanical, thermal, structural, and biological properties. Particle size ranged from ۱۸۰ to ۲۳۰ nm, with slight increases upon IBU loading, indicating stable polymer dispersions. Viscosity (۴,۳۰۰–۵,۹۵۰ cP) and gel content (۶۸–۷۹%) increased with HEMA and BA content, reflecting stronger intermolecular interactions. GPC analysis confirmed controlled molecular weight (Mw ۲۶۰–۳۴۵ kg/mol, PDI ۲.۳۳–۲.۵۵). DSC results showed that Tg increased with HEMA incorporation and drug loading, demonstrating enhanced thermal stability. X-Ray Diffraction (XRD) analysis revealed that all synthesized PSA formulations were predominantly amorphous, as indicated by the absence of sharp crystalline diffraction peaks. The lack of distinct crystalline reflections for ibuprofen in the drug-loaded systems suggested that IBU was molecularly dispersed within the polymer matrix rather than present in crystalline form. This amorphization is attributed to strong interactions between the drug and functional groups of the acrylate copolymers, particularly hydrogen bonding with HEMA-containing formulations, which further supports improved drug dispersion and controlled release behavior. Adhesive tests revealed that HEMA- and BA-rich formulations exhibited superior tack, ۱۸۰° peel adhesion, and shear strength. Drug release studies indicated slower IBU release from HEMA-rich PSAs due to hydrogen bonding and functional-group interactions. Importantly, in vitro MTT assays confirmed high biocompatibility (>۹۰% cell viability) for all formulations, demonstrating minimal cytotoxicity. These results highlight that systematic monomer selection and ratio optimization enable the development of PSAs with tailored mechanical properties, controlled drug release, thermal stability, amorphous drug dispersion, and excellent biocompatibility.

کلیدواژه ها:

Drug delivery systems ، Pressure-sensitive adhesive ، Acrylic-adhesive ، Ibuprofen