SYNTHESIS AND EVALUATION OF PHTHALATE ANALOGUE OF DICLOFENAC AGAINST FREUND’S COMPLETE ADJUVANT INDUCED ARTHRITIS IN RAT Original Article P. MANIMEKALAI * , K. M. PREETU SHUKLA, P. SUDHAKAR, G. MURUGANANTHAN Swamy Vivekanandha College of Pharmacy, Thirunchengode 637205 Email: mekalaivel@gmail.com Received: 01 Sep 2019, Revised and Accepted: 16 Nov 2019 ABSTRACT Objective: The objective of the present study is to evaluate the effect of Phthalate analogues of diclofenac in Freund’s complete adjuvant (FCA) induced Arthritis in the rat. Methods: Twenty four female albino wistar rats were enrolled in this study and are divided into 4 groups (six each). The groups were designed as follows: Group I: vehicle control, Group II: arthritic control, Group III: diclofenac treated, Group IV: phthalate analogue of diclofenac treated. Various assessments such as anti-arthritic activity, biochemical estimations, haematological parameters, ulcerogenesis, radiological and histopathological studies were evaluated. Results: Arthritic control group exhibited significant increase in the level of paw volume, arthritic score (p<0.0001), Serum glutamic pyruvic transaminase (SGPT) (p<0.001), Serum glutamic oxaloacetic transaminase (SGOT) p<0.01), rheumatoid arthritis factor, C-reactive protein (CRP), White Blood Cells (WBC), Creatinine and uric acid and a significant decrease in Red Blood Cells (RBC). Increased swelling of joints, bony destruction and profound ulceration were observed in the Arthritic control group. All these conditions were reversed in diclofenac and phthalate analogue of diclofenac groups. Conclusion: We conclude that phthalate analogue of diclofenac shows potent anti-arthritic activity with milder ulceration when compared to diclofenac treatment. Keywords: Diclofenac, Freund’s Complete Adjuvant (FCA), Phthalate moiety, Rheumatoid arthritis © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open-access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) DOI: http://dx.doi.org/10.22159/ijpps.2019v11i12.32537 INTRODUCTION Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease with the main clinical manifestation of systemic complications including synovial inflammation, joint lesion and bone damage [1]. In RA, pannus is rich in secretion of activated macrophages and other inflammatory mediators, resulting in the destruction of tissues when compared to normal synovial fluid, which is essentially a cellular [2]. One of the most important groups of mediators in RA is cytokines. The most prominent of these include TNF, IL-1, and IL-6, which are released in the synovial microenvironment [3, 4]. Rheumatoid arthritis is also characterized by the presence of autoantibodies known as rheumatoid factors (RF) and anti-citrullinated peptide antibodies (ACPA). Therefore RA synovial fluid is abundant in neutrophils, macrophages, T lymphocytes, autoantibodies and dendritic cells. Chondrocytes secrete proteolytic enzymes that lead to destruction of articular cartilage causing bone deformity and loss of joint function. It is thought that costimulation of both humoral and cellular immunity may contribute to the pathology of the disease [5]. RA affects all the races, where the female population is affected three times more than the male population. The cause of RA is still a mystery. The management of RA includes Nonsteroidal anti- inflammatory Drugs (NSAIDs), Glucocorticoids, Disease-Modifying Anti-Rheumatic Drugs (DMARDs) and Biologic agents [6]. Among the most popular NSAIDs worth mentioning is diclofenac ranked 30th among the top 200 drugs with respect to new prescriptions. Diclofenac sodium has been demonstrated to have antipyretic activity and to be an effective analgesic in rats and mice and in therapeutic trials in patients with rheumatoid arthritis, osteoarthritis or pain of varying origin [7]. Despite the intensive research that has been aimed at the development of diclofenac, their clinical usefulness is still restricted by their gastrointestinal side effects like gastric irritation, ulceration, bleeding, perforation and also cardiovascular complications. Hence, the scope of the research widens for the newer, effective and safer alternative medicine. Gastrointestinal (GI) toxicity is attributed to direct contact of free carboxylic acid (–COOH) moiety present on diclofenac sodium with GI mucosal cells [7]. Hence as an alternative approach, in order to avoid major GI side effects, we have focused our research work on Synthetic derivatization based upon chemical modification of diclofenac structure. Therefore we have attempted to design phthalate analogue of diclofenac by replacing free acidic group on diclofenac structure by the most potent less acidic heterocyclic ligand–phthalate moiety. The latter showed negligible GI toxicity, due to very good selective interactive energies with cyclooxygenase-2 (COX-2) when compared to that of diclofenac sodium [8]. Hence the present study was therefore aimed to synthesize and evaluate phthalate analogue of diclofenac and was designed to investigate whether the synthesized compound exerts an ameliorative effect on arthritis in rats exposed to Freund’s complete adjuvant (FCA) and to ascertain its potential mechanism with less ulcerogenicity. MATERIALS AND METHODS Selection and synthetic scheme of the phthalate analogue of diclofenac Diclofenac sodium was hydrolyzed using concentrated sulphuric acid to convert salt to acid. The obtained intermediate was refluxed for 22 h with absolute alcohol and concentrated sulphuric acid. The obtained ethyl ester reaction mixture was sodium bicarbonate solution and recrystalised with methanol. The recrystalised ester was refluxed with hydrazine hydrate along with absolute alcohol for 22 h. Finally the precipitated mixture was filter dried and recrystalised from methanol. Yield: 87.44%, mp: 112 °C. Acute oral toxicity studies of phthalate analogue of diclofenac– OECD 423 guideline Acute oral toxicity studies were performed using a phthalate analogue of diclofenac at the dose level of 300 mg/kg orally in mice. Animals Healthy adult female Albino Wister Rats (150-200 g: 24 rats) were obtained from Swamy Vivekananda College of Pharmacy, Tiruchengodu. International Journal of Pharmacy and Pharmaceutical Sciences Print ISSN: 2656-0097 | Online ISSN: 0975-1491 Vol 11, Issue 12, 2019