| Styrene-isoprene-styrene (SIS) based HMPSAs have many advantages, such as strong cohesion and high drug loading. However, since SIS is very hydrophobic, HMPSAs prepared with SIS can only be applied for lipophilic drugs and usually lead to skin irritation, which greatly restricts their application in TDDS.Based on the blend of styrene-isoprene-styrene (SIS) thermoplastic elastomer and acrylic resin Eudragit EPO, amphiphilic hot-melt pressure sensitive adhesives (HMPSAs) were fabricated. Compatibility and micromorphology of SIS/EPO blends (SEBs) were analyzed with differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results showed that when the mass ratio of SIS to EPO was1:1-1:2, bicontinuous structure was formed. Following the addition of an appropriate amount of polyethylene glycol (PEG), mineral oil and C5resin, the amphiphilic HMPSAs were prepared. Becauce of the compatibility between SIS and EPO, as well as the hydrogen bond interaction between EPO and PEG, amphiphilic HMPSAs showed good thermostability. The adhesive performance of HMPSAs were measured with180°peeling strength and holding power. Geniposide and oleanolic acid were used as model drugs to investigate drug release behavior. When PEG6000was used and the mass ratio of PEG to SEB was13:30～16:30, the HMPSAs could maintain good adhesion performance and achieve continual release of both hydrophilic and lipophilic drugs. In weakly acidic conditions, the HMPSAs exhibited good hygroscopicity and release profile due to the protonation of EPO, it was shown that pH sensitive amphiphilic HMPSAs were more suitable for transdermal drug delivery system(TDDS). |
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