A novel drug delivery system based on kaemite/carvedilol composite for sustained release of carvedilol

a drug delivery system based on k anemite/carvedilo (Ka/CV) composite for sustained release of carvedilol (CV) has been constructed by protonation, intercalation, and ionic exchange process. Structure and compositional analyses revealed that the initial Na-kanemite (Na-Ka) was an orthorhombic structure with chemical formula of NaHSi 2 O 4 (OH) 2 ·2.52H 2 O. When the Na-Ka was protonated with HCl solution, the yielding H-kanemite (H-Ka) was also an orthorhombic structure with chemical formula of be H 2 Si 2 O 4 (OH) 2 ·0.60H 2 O. After the H-Ka was reacted with tetrabutylammonium hydroxide (TBAOH) solution, a colloid suspension consisting of TBA + and Ka (TBA-Ka) formed, and the TBA-Ka sediment exhibited amorphous state. Further, while the TBA-Ka colloid suspension was reacted with carvedilo hydrochloride solution, the Ka/CV composite formed, and its chemical formula was estimated to be H 1.08 [(C 24 H 27 N 2 O 4 ) + 0.92 ]·Si 2 O 4 (OH) 2 ·6.70H 2 O. The loading capacity of Ka/CV for CV was about 57.60%. Drug release revealed that the Ka/CV composite showed extremely slow and sustained release of CV in phosphate buffer solution (PBS, pH = 7.40), and the releasing percentages of CV were 4.09, 5.81, 7.06, 7.62, and 7.64% after 6, 12, 24, 48, and 96 h, respectively. This extremely slow and sustained release of CV may be important in maintaining effective drug concentrations in the bloodstream with a single administration, thereby enhancing therapeutic efficacy and improving drug availability.