Cress seed mucilage based buccal mucoadhesive gel of venlafaxine: in vivo, in vitro evaluation Pankaj Padmakar Nerkar • Surendra Ganeshlal Gattani Received: 22 April 2011 / Accepted: 9 December 2011 / Published online: 28 December 2011 Ó Springer Science+Business Media, LLC 2011 Abstract Venlafaxine is a newer antipsychotic drug which shows first pass effect. Cress seed is also called as garden cress or green salad. This study examined the mechanical (gel strength, adhesiveness) and rheological properties of cress seed mucilage based gels that contain different ratios of carbopol 934 P (0.5–1.5%). In addition, diffusion of venlafaxine from gel formulations was evalu- ated. The selected formulation was further analyzed for pharmacokinetic parameters in rabbits. All formulations exhibited pseudoplastic flow with thixotropy. Formulation F5 showed the C max of 24.19 ± 0.72 ng/ml by buccal route of administration and 17.98 ± 1.15 ng/ml by oral route of administration. The bioavailability of F5 by buccal route was 54.44% and that of by oral route was 39.60%. A combination of the cress seed mucilage and carbopol 934 P resulted in a prolonged and higher venlafaxine delivery by buccal route of administration. 1 Introduction The properties of pure synthetic polymers and those of pure biological polymers alone are often inadequate to produce materials with good combination of chemical, mechanical, thermal and biological performance characteristics [1]. Therefore a new material has been prepared by blending of cress seed mucilage and carbopol 934 P. Cress is an annual, tall, glabrous herb with erect stem widely distributed in many countries of world. In India, China and far eastern countries the seeds are used for the cure of dysentery, asthma, piles, as diuretic, as aphrodisiac, in abdominal colic, pleurisy and dropsy. Cress seeds analysis showed that it consist of three fractions as whole meal, endosperm and bran. Chemically these fractions consist of amino acids (glutamic acid), essential amino acids and fatty acids (linolinic and erucic acid). Cress seeds are reported to consist of 15% of the mucilage [2, 3]. Carbopol 934 P is a carboxy polymethylene derivative, having excellent thickening, emulsifying and gelling property. It is the most bioadhesive synthetic polymer reported in buccal mucoadhesive dosage forms. Carbopol ionizes and acquires anionic charge. Therefore to study the synergistic effect of the carbopol and cress seed mucilage with minimum quantity is chosen. Gels and hydrogels find very important place in buccal mucoadhesive drug delivery system. Buccal mucoadhesive gels are having advantages such as it can be applied over larger surface area, can be easily removed and it can improve absorption by adhering to the buccal mucosa. Gels can be applied to all parts of buccal mucosa i.e., sublingual, buccal and palatal region due to the flexibility in its structure [4]. Venlafaxine is an antipsychotic drug. It is prescribed in schizophrenia, anxiety and depression etc. Venlafaxine is a unique antidepressant that differs structurally from other antidepressants. Venlafaxine and its active metabolite inhibit the neuronal uptake of norepinephrine serotonin and to a lesser extent dopamine but have no monoamine oxidase inhibitory activity and a low affinity for brain muscarinic, cholinergic, histaminergic or alpha adrenergic receptors. Venlafaxine is available as conventional tablet P. P. Nerkar Department of Pharmaceutics, R.C. Patel Institute of Pharmaceutical Education & Research, Karwand Naka, Dist-Dhule, Shirpur 425 405, Maharashtra, India e-mail: nerkarpankaj@rediffmail.com S. G. Gattani (&) S. R. T. M. University, Vishnupuri, Nanded, Maharashtra, India e-mail: sggattani@rediffmail.com 123 J Mater Sci: Mater Med (2012) 23:771–779 DOI 10.1007/s10856-011-4529-7