Abstract
Short half-life and low bioavailability of Venlafaxine hydrochloride (VF), an
antidepressant drug, necessitates the frequent administration of VF tablets in a
day in order to maintain adequate drug concentration in blood plasma. This
generates the need for the development of formulations which could prolong the
release of VF and reduce the multiple dosages. The present work explores the
combination of Montmorillonite (Mt) with Pluronic F-68 (PF-68) (OrganoMT) for
oral delivery of VF. The effect of various parameters including pH of aqueous
drug solution, contact time and initial drug concentration on drug loading
capacity of OrganoMT has been studied. The synthesized OrganoMT-VF complexes
were characterized by various suitable techniques. XRD studies indicated that
the VF molecules were intercalated within the OrganoMT layers. In vitro release
behavior of VF from OrganoMT-VF complexes shows an extended-release pattern for
a period of 30 h and reaches upto 70% and 60% compared
to pure VF having complete release time of 5.5 h and 3.5 h in
simulated gastric and intestinal fluid respectively. Various kinetic models were
employed to elucidate the drug release mechanism where the best fitting was
obtained with Korsmeyer Peppas model. The results suggest the possibility of
designing an oral extended controlled release formulation for VF to minimize its
administration frequency thereby increasing the effectiveness of drug. This
improves patient compliance by reducing the dose from 4 times in 24 h to
once in 24 h.
Key words
Pluronic F-68 - Venlafaxine hydrochloride - Oral extended release - Montmorillonite