Development and evaluation of liquid oral controlled release systems for Losartan potassium

Losartan potassium is a water soluble antihypertensive agent with short half-life. Controlling its release will improvepatient compliance. The benefit will be extended for geriatric patients if the developed system was liquid. The objectiveof this work was to develop controlled release oral liquid losartan potassium. This employed a combination of in situgelation and coating drug particles with pH-dependent polymer (Eudragit® L100). Solid dispersion (SD) prepared at1:1, 1:1.5, and 1:2 drug : polymer ratios, respectively. Sodium alginate solution was loaded with either pure drug orSD, in presence and absence of 1% w/v chitosan. These systems were evaluated for the drug release using continuouspH variation study. Alginate formulation with pure drug underwent in situ gelation in the gastric conditions but lost thegelling strength in the intestinal phase with burst drug release. Loading the formulation with SD resulted in controlleddrug release both in the gastric and intestinal phases. Increasing eudragit concentration in SD decreased the drugreleased with total release efficiency of 62.1%, 53.0%, and 41.7%. Incorporation of chitosan at reduced further drugrelease rate reaching 21% at the higher eudragit concentration. The study provided the formulator with a range of oralliquid formulations for controlled release of losartan potassium.