Abstract:
The Aim of present investigation was to develop microbeads of Labetalol hydrochloride
using chitosan-gellan gum polymer to increase the gastric retention of the dosage form to
avoid precipitation of drug in the intestine. Labetalol Hydrochloride is a non-selective α,
β-adrenoreceptor antagonist is used in the treatment of hypertension. It is appreciably
soluble in lower and higher pH solutions with minimum solubility between pH 6 to 10.
The main objective was attempt to increase the gastric retention of drug from dosage
form for beneficial in the drug absorption in favour of preventing precipitation of drug in
alkaline pH. The microbeads were prepared by Ionotropic gelation method, using
polymers like gellan gum and chitosan. The prepared microbeads were optimized on the
basis of entrapment efficiency, floating buoyancy, mucoadhesion. The optimized
microbeads were further evaluated for floating time, percentage yield, percentage drug
loading, micromeritic properties, in vitro drug release studies and surface morphology by
SEM. The formulated microbeads were free flowing and SEM studies indicated that the microbeads were porous, irregular having rough and dense surface with microscopic
cracks and wrinkles on the surface. The Optimized formulation which had a composition
of 2% gellan gum, 0.5% of chitosan, 0.4% of NaHCo3. The microbeads showed percentage
drug entrapment of 89.34%, percentage floating buoyancy of 76.59% and percentage
mucoadhesion 78%. In vitro drug release studies showed a sustained release of drug up to
12 hrs. The mechanism of drug release from microbeads was observed to follow zero order
kinetics on the basis of R2 value (Regression Coefficient) of various mathematical kinetic
models. The data obtained in this study thus suggests that a micro particulate microbeads
form of Labetalol Hydrochloride can be successfully designed to give sustained drug
delivery.
