Construction and in vitro/ in vivo evaluations of pulse sustained release of verapamil hydrochloride delivery system.

To prepare a porous cation exchange resin excipient and a verapamil hydrochloride (VH) pulse sustained release suspension and to evaluate its in vitro release and in vivo pharmacokinetics. Porous cation exchange resin was prepared using suspension polymerization and sulfonation reaction. A drug-resin complex was formed via impregnation and coating, then formulated into a suspension. In vitro release profiles and pharmacokinetics in Sprague-Dawley rats were investigated. The custom-made resin complied with the relevant requirements of the United States Pharmacopeia, with a 2.6-fold higher surface area and 1.5-fold greater exchange capacity than IRP69. Compared with a conventional VH tablet (Tmax 2 h, t1/2 1.407 h), the suspension delayed Tmax to 5 h and extended t1/2 to 4.191 h, exhibiting both enteric dissolution and sustained release characteristics. The findings showed that a verapamil hydrochloride pulsatile release suspension prepared with custom-made porous cation exchange resin achieved controlled and sustained release, potentially improving adherence in cardiovascular therapy by better aligning with disease progression. It is also likely to reduce dosing frequency and plasma concentration fluctuations, offering significant clinical value in the personalized management of conditions such as hypertension and angina.