_____________________________________________________________________________________________________ *Corresponding author: E-mail: jaswanthkumar877@gmail.com; Journal of Pharmaceutical Research International 33(20B): 11-20, 2021; Article no.JPRI.67200 ISSN: 2456-9119 (Past name: British Journal of Pharmaceutical Research, Past ISSN: 2231-2919, NLM ID: 101631759) Application of RP-HPLC for the Estimation of Allopurinol and Its Related Substances in Bulk and Tablet Dosage Form Ch. Jaswanth Kumar 1* , Prachet Pinnamaneni 1 , Siva Prasad Morla 1 , K. N. Rajini Kanth 1 and Rama Rao Nadendla 1 1 Chalapathi Institute of Pharmaceutical Sciences, Lam, Guntur-522034, Andhra Pradesh, India. Authors’ contributions This work was carried out in collaboration among all authors. Author CJK’ designed the study, performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript. Authors PP and SPM managed the analyses of the study. Authors KNRK and RRN managed the literature searches. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JPRI/2021/v33i20B31354 Editor(s): (1) Dr. Mohamed Fathy, Assiut University, Egypt. Reviewers: (1) Ralitsa Balkanska, Institute of Animal Science, Bugaria. (2) D. Santhi Krupa, Vijaya Institute of Pharmaceutical Sciences for Women, India. (3) Naheed Akhter, Government College University, Faisalabad, Pakistan. Complete Peer review History: http://www.sdiarticle4.com/review-history/67200 Received 03 February 2021 Accepted 30 March 2021 Published 05 April 2021 ABSTRACT Aims: The main aim of the present study was to develop and validate a simple and cost- effective method for the estimation of allopurinol and its related substances by using RP-HPLC. Study Design: Estimation of Allopurinol and its related substance in bulk and tablet dosage forms by RP-HPLC. Place and Duration of Study: Chalapathi Drug Testing Laboratory, Chalapathi Institute of Pharmaceutical Sciences, Chalapathi Nagar, Lam, Guntur-522034 between October 2020 to January 2021. Methodology: Method development was carried out by using Schimadzu, Prominence-i series LC 3D-Plus autosampler embedded with lab solutions software, equipped with PDA detector using YMC column (150 mm X 4.6 mm, 3 μm) and 0.1M Ammonium acetate buffer as a mobile phase in the ratio of 100% at a flow rate of 1.0 ml/min at a wavelength of 255nm. The developed method was validated according to ICH guidelines. Original Research Article