Floating molecularly imprinted polymers based on liquid crystalline and polyhedral oligomeric silsesquioxanes for capecitabine sustained release.

Molecularly imprinted polymers (MIPs) have drawn extensive attention as carriers on drug delivery. However, most of MIPs suffer from insufficient drug loading capacity, burst release of drugs and/or low bioavailability. To solve the issues, this study designed an imprinted material with superior floating nature for oral drug delivery system of capecitabine (CAP) rationally. The MIPs was synthesized in the presence of 4-methylphenyl dicyclohexyl ethylene (liquid crystalline, LC) and polyhedral oligomeric silsesquioxanes (POSS) via polymerization reaction. The LC-POSS MIPs had extended release of the template molecules over 13.4 h with entrapment efficiency of 20.53%, diffusion coefficient of 2.83 × 10 ^-11  cm ²  s ^-1 , and diffusion exponent of 0.84. Pharmacokinetic studies further revealed the prolong release and high relative bioavailability of CAP in vivo of rats, showing the effective floating effect of the LC-POSS MIPs. The in vivo images revealed visually that the gastroretentive time of the LC-POSS MIPs was longer than non-LC-POSS imprinted polymers. The physical characteristics of the polymers were also characterized by nitrogen adsorption experiment, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry analysis. As a conclusion, the LC-POSS MIPs can be used as an eligible CAP carrier and might hold great potential in clinical applications for sustained release drug.
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