ANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF DEXMETHYLPHENIDATE AND SERDEXMETHYLPHENIDATE BY USING RP-HPLC IN BULK AND PHARMACEUTICAL DOSAGE FORM Original Article SUNIL RAYUDU 1 , M. MANORANJANI 2,* , D. RAMA SEKHARA REDDY 3 1,3 Department of Chemistry, Krishna University, Machilipatnam 521004, AP, India, 2 Department of Chemistry, PB Siddhartha College of Arts and Science, Vijayawada 520010, AP, India * Email: drmanoranjani@gmail.com Received: 03 Nov 2021, Revised and Accepted: 15 Dec 2021 ABSTRACT Objective: The current investigation was pointed at developing and progressively validating novel, simple, responsive and stable RP-HPLC method for the simultaneous measurement of active pharmaceutical ingredients of Dexmethylphenidate and Serdexmethylphenidate. Methods: A simple, selective, validated and well-defined stability that shows isocratic RP-HPLC methodology for the simultaneous determination of Dexmethylphenidate and Serdexmethylphenidate. The chromatographic strategy utilized inertsil ODS column of dimensions 250x4.6 mm, 5 µ, using isocratic elution with a mobile phase of acetonitrile and 0.1% orthophosphoric acid (70:30). A flow rate of 1 ml/min and a detector wavelength of 262 nm utilizing the PDA detector were given in the instrumental settings. Recovery, specificity, linearity, accuracy, robustness, ruggedness were determined as a part of method validation and the results were found to be within the acceptable range. Validation of the proposed method was carried out according to an international conference on harmonization (ICH) guidelines. Results: LOD and LOQ for the active ingredient were established with respect to test concentration. The calibration chart plotted was linear with a regression coefficient of R 2 >0.999, which means the linearity was within the limit. Conclusion: The proposed method to be fast, simple, feasible and affordable in assay condition. During stability tests, it can be used for routine analysis of production samples and to verify the quality of drug samples during stability studies. Keywords: Dexmethylphenidate, Serdexmethylphenidate, RP-HPLC, Development, Validation © 2022 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/) DOI: https://dx.doi.org/10.22159/ijap.2022v14i2.43515. Journal homepage: https://innovareacademics.in/journals/index.php/ijap INTRODUCTION Dexmethylphenidate, sold under the brand name Focalin among others, is a medication [1, 2] used to treat attention deficit hyperactivity disorder (ADHD) [3, 4] in those over the age of five years. If no benefit is seen after four weeks, it is reasonable to discontinue its use. It is taken by mouth [5]. The immediate-release formulation lasts up to five hours, while the extended-release formulation lasts up to twelve hours. Common side effects include abdominal pain [6, 7], loss of appetite [8], and fever [9, 10]. Serious side effects may include abuse [11], psychosis [12], sudden cardiac death [13, 14], mania [15], anaphylaxis [16], seizures [17], and dangerously prolonged erection. Safety during pregnancy and breastfeeding is unclear. Dexmethylphenidate is a central nervous system (CNS) stimulant [18]. How it works in ADHD is unclear. It is the more active enantiomer of methylphenidate. Serdexmethylphenidate (SDX) is a prodrug of dexmethylphenidate created by the pharmaceutical company KemPharm. The compound was first approved by the FDA as one of the active ingredients in Azstarys for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children, adolescents, and adults in March 2021. Co-formulation of SDX with dexmethylphenidate allows for a more rapid onset of action while still retaining up to 13 h of therapeutic efficacy. Due to the delayed onset and prolonged duration of effects following oral administration of SDX, several dosage forms containing SDX are currently under investigation for use as long-acting psychostimulant [19, 20] in the treatment of various CNS disorders [21], substance use disorder (SUD) [22, 23], and sleep disorders [24]. Under the developmental codename KP484, SDX is being investigated as part of a potential "super-extended duration" psychostimulant, with therapeutic efficacy lasting up to 16 h following oral administration. The aim of the study is to estimate the pharma ingredients Dexmethylphenidate and Serdexmethylphenidate by using RP-HPLC. H N O H O N O O O N + NH OH OH O O O Cl- A B Fig. 1: Structure of (A) Dexmethylphenidate and (B) Serdexmethylphenidate Till today there is only one HPLC method [25] was reported in the literature. Hence we developed a method for the quantification of Dexmethylphenidate and serdexmethylphenidate. The developed HPLC method was utilized for the estimation of the drug by in vitro method. MATERIALS AND METHODS Chemicals Acetonitrile (HPLC-grade), orthophosphoric acid, water were purchased from Merck India Ltd, Mumbai, India. APIs of International Journal of Applied Pharmaceutics ISSN- 0975-7058 Vol 14, Issue 2, 2022