Preparation and Characterization of Sustained release Antidepressant tablet using combination of wax

Abstract

Developing oral controlled release tablets for highly water soluble drugs with constant release rate has always been a challenge to the pharmaceutical technologist. Most of these highly water soluble drugs if not formulated properly, may readily release the drugs at faster rate, and are likely to produce the toxic concentrations of the drug on oral administration. Various waxes such as fatty acids, fatty alcohols, natural waxes and glycerides have been used, that melts at relatively low temperature and solidifies at room temperature to form solid dosage forms for decades. Drug release is decreased from the matrix with the increased molecular weight of the wax. When single wax is used as a binder, for sustained release, the concentration of wax needed is higher for obtaining required drug release profile. Venlafaxine Hydrochloride is a novel antidepressant which is highly water soluble. It is unique antidepressant that differs structurally from other currently available antidepressants. Venlafaxine and its active metabolite, O-desethyl venlafaxine (ODV), inhibits the neuronal uptake of norepinephrine, serotonin and to a lesser extent dopamine but have  no monoamine oxidase inhibitory activity and low affinity for brain muscarnic, cholinergic, histaminergic or alpha-adrenergic receptors. Hence it lacks the adverse cholinergic, sedative and cardiovascular effects of tricyclic antidepressants. Melt granulation was used as method of preparation. It is advantageous compared with an ordinary wet granulation process, since the liquid addition phase as well as drying phase of the process is eliminated. it can be concluded that sustained release wax matrix tablets were prepared successfully using the combination of carnauba wax and Hydrogenated castor oil for a highly water soluble drug, Venlafaxine Hydrochloride.