Citation: Chandan Mohanty & KV Subrahmanyam. In-Vivo Pharmacokinetic Study of Matrix Tablets of Atenolol Prepared by Sintering Technique. Sch Acad J Pharm, 2021 Apr 10(4): 71-76. 71 Scholars Academic Journal of Pharmacy Abbreviated Key Title: Sch Acad J Pharm ISSN 2347-9531 (Print) | ISSN 2320-4206 (Online) Journal homepage: http://saspublishers.com In-vivo Pharmacokinetic Study of Matrix Tablets of Atenolol Prepared by Sintering Technique Chandan Mohanty 1* , KV Subrahmanyam 2 1 Guru Nanak Institutions Technical Campus-School of pharmacy, Ibrahimpatnam, Hyderabad-501506, Telangana, India 2 Siddhartha Institutions of Pharmacy, Narapally (V), Ghatkesar (M), Hyderabad-501506, Telangana, India DOI: 10.36347/sajp.2021.v10i04.003 | Received: 21.02.2021 | Accepted: 10.04.2021 | Published: 13.04.2021 *Corresponding author: Chandan Mohanty Abstract Original Research Article The present study involved in-vivo pharmacokinetic evaluation of sintered matrix tablets of Atenolol in comparison to Atenolol pure drug and unsintered matrix tablets of Atenolol. The objective of the present investigation was to study the effect of sintering technique in development of controlled release dosage form. The Atenolol pure drug solution, both formulated unsintered and sintered controlled release matrix tablets of Atenolol were tested for in-vivo pharmacokinetic study in healthy male New Zealand rabbits (n=3). The plasma concentrations of Atenolol drug were determined by a validated HPLC method. From the time versus plasma drug concentration data, various pharmacokinetic parameters (C max , T max , AUC, K E and t 1/2 ) were estimated. T max for pure drug, unsintered and sintered tablets was found to be 2h, 3hr and 4h with C max values of 751.00 ± 10.53 ng/ml, 639.33± 10.40 ng/ml and 518.00 ± 8.54 ng/ml respectively. Increase of T max values in sintered tablets as compared to the of pure drug and unsintered tablets suggested slow absorption of drug from the formulated sintered tablets and the availability of drug at a controlled manner. An increase of the elimination half- life (T 1/2 ) and decrease in elimination rate constant (K E ) of drug in sintered matrix tablet in comparison to the that of unsintered tablets and pure drug was also observed, indicating the prolonged and controlled systemic availability of drug in biological system. The investigated sintered matrix tablets exhibited a remarkable increase in bioavailability due to prolonged plasma residence and could maintain constant plasma level of atenolol up to 24 hr in rabbits. Key words: In-vivo, Sintering, Pharmacokinetic Parameters, Controlled release, Matrix Tablet, Atenolol. Copyright © 2021 The Author(s): This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY-NC 4.0) which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use provided the original author and source are credited. INTRODUCTION Atenolol (2-(4-{2-hydroxy-3-[(propan-2-yl) amino] propoxy} phenyl) acetamide) is a selective β1 receptor blocker, widely prescribed in hypertension, arrhythmias, angina pectoris, and myocardial infraction. Atenolol is included in class III category of BCS (biopharmaceutics classification system), that is high aqueous solubility and low gastrointestinal permeability [1]. The absorption of Atenolol after oral administration is rapid (peak plasma levels reaches in 2-4 hr) and consistent but incomplete [2]. Moreover, Atenolol has been reported to undergo extensive hepatic first-pass metabolism. Hence, oral bioavailability of Atenolol is only 50-60% and left behind being excreted unchanged in feces. In antihypertensive treatment, the oral dose of Atenolol is 50 mg in conventional release system, twice a daily. But administration of conventional release tablets of Atenolol has been reported to exhibit fluctuations in plasma concentration of the drug, resulting either in adverse effects due to systemic accumulation of drug like nausea, ischemic colitis, diarrhoea and mesenteric thrombosis or decrease in concentration of drug at the receptor site. This combined with low oral bioavailability of atenolol make it suitable drug for the design of sustained release formulation to maintain a proper blood level of drug for a long time without fluctuation [1, 3]. The concept of sintering in pharmaceutical sciences is relatively new, but the research interests related to this process have been growing continuously. In powder metallurgy, sintering is defined as bonding of adjacent particle surfaces in a mass of powder or in compact, by the application of heat. Conventional sintering technique involves the heating of compact at a temperature below the melting point of the solid constituent in controlled environment under atmospheric pressure [4, 5]. In the pharmaceutical science, sintering has been described as the mechanism Pharmacy