Available online at www.scholarsresearchlibrary.com Scholars Research Library Der Pharmacia Lettre, 2011: 3 (4) 227-240 (http://scholarsresearchlibrary.com/archive.html) ISSN 0974-248X USA CODEN: DPLEB4 227 Scholar Research Library Studies in formulation development of chronotherapeutics dosage of model drug Kinjal T. Patel, Ashok N. Mahajan, Dushyant A. Shah A.P.M.C. College of Pharmaceutical Education and Research, Motipura, Himatnagar ______________________________________________________________________________ ABSTRACT The objective of the present work is to develop hollow calcium pectinate beads for floating pulsatile release of aceclofenac intended for chronopharmacotherapy. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release in alkaline medium. To overcome limitations of various approaches for peparation of buoyance, hollow and porous beads were simple process of acid-base reaction during ionotropic cross linking was adopted. Formulations where studied for swelling properties, in-vitro release characteristics and swelling–erosion properties. As increased in concentration of oil, increases floating time but decreases drug release after optimized concentration. The dissolution Tests were carried out in a USP paddle dissolution apparatus. The formulation was optimized by 3 2 factorial design. The optimized batch obtained had porous, hollow with a bulk density <1 and had a floating time of > 20 hrs. It also showed highest % of drug release with 99.805 % entrapment efficiency. It showed lowest swelling ratio in 0.1 N HCl and highest swelling ratio in pH 6.8 phosphate buffer. The floating beads showed a two-phase release pattern with initial lag phase during floating in an acidic medium followed by rapid pulse in phosphate buffer pH 6.8. The approach indicates the use of hollow calcium pectinate beads as a promising floating pulsatile drug delivery system for site- and time-specific release of drug acting as per chronotherapy. Keywords: Chronopharmacotherapy, Pulsatile drug delivery, Aceclofenac, Oil-entrapped beads. ______________________________________________________________________________ INTRODUCTION In the field of modified release, there has been a growing interest in time specific oral delivery, which generally refers to the pre-programmed release of drugs following administration to achieve improved therapeutic efficacy. These systems constitute a relatively new class of devices, the importance of which is especially connected with the recent advances in chronopharmacology [1]. Particular rhythms in the onset and extent of symptoms were observed in diseases such as, bronchial asthma, myocardial infarction, angina pectoris, rheumatic disease, ulcer, diabetes, attention deficit syndrome, hypercholesterolemia and hypertension [2]. Natural biodegradable polysaccharides like pectin, guar gum, chitosan, carrageenans, sodium alginate,