Utilizing guar gum for development of "tabs in cap' system of losartan potassium for chronotherapeutics

The project was aimed to achieve biphasic pulsed drug release of losartan potassium by fabricating 'Tabs in cap' system wherein drug loaded tablets sandwiched the erodible guar gum time spacer tablet. The system was capsulated in non biodegradable body capped with water soluble cap. The system was investigated for in-vitro release and ex-vivo continuous dissolution-absorption and stability. The influence of spray dried lactose (SDL): guar gum ratio on lag time was investigated. In-vitro release capsule evidenced immediate release followed by delayed pulse (>90%) and a lag time 6h was achieved by maintaining an optimum ratio of SDL: guar gum in erodible guar gum tablet. Ex-vivo continuous dissolution-absorption study demonstrated two successive pulses for dissolution and indicated delay in absorption of drug. Histological study revealed viability of intestinal cells and the system had shelf- life of 15 months. Conclusively, using guar gum spacer tablet, biphasic pulsed drug release 'Tabs in Cap' system of losartan potassium was successfully developed that has potential for chronotherapeutics in hypertension.