MINISTRY OF HEALTH HANOI UNIVERSITY OF PHARMACY VU THI DIEM QUYNH DEVELOPMENT OF A DISSOLUTION TESTING METHOD FOR EBASTINE DISPERSIBLE TABLETS PHARMACIST GRADUATION THESIS HANOI – 2025 MINISTRY OF HEALTH HANOI UNIVERSITY OF PHARMACY VU THI DIEM QUYNH Student ID: 2001519 DEVELOPMENT OF A DISSOLUTION TESTING METHOD FOR EBASTINE DISPERSIBLE TABLETS PHARMACIST GRADUATION THESIS Supervisors: Assoc. Nguyen Thi Thuan Site of implementation: Department of Pharmaceutical Chemistry - Faculty of Pharmaceutical Chemistry and Technology, Hanoi University of Pharmacy HANOI – 2025 ACKNOWLEDGEMENTS Before presenting the contents of my thesis, I would like to express my sincere gratitude to all those who have consistently accompanied, supported and encouraged me throughout my conducting research time at the Department of Pharmaceutical Chemistry – Hanoi University of Pharmacy. First and foremost, I would like to extend my deep and heartfelt thanks to Assoc. Nguyen Thi Thuan – Lecturer at the Department of Pharmaceutical Chemistry, Hanoi University of Pharmacy, who has dedicatedly guided, supported, and provided optimal conditions for me during the research process and the completion of my graduation thesis.
I would also like to express my gratitude to all the lecturers and technicians at the Department of Pharmaceutical Chemistry, Hanoi University of Pharmacy, who have always assisted and facilitated my graduation research. Special thanks to Mr. Duong Tien Anh, Ms. Hoang Thi Loan, Ms.
Tran Thu Hang, Ms. Chu Thi Trang, Mr. Bui Van Quan, Ms. Nguyen Tuyet Mai, and the students of K76, H1K2 in my laboratory, for their constant companionship and support throughout the research process in the department.
Moreover, I would like to extend my appreciation to my wonderful friends from Group 14 A1K75 and Group 6 M1K75, who have shared every joy and sorrow with me, created the most supportive and understanding environment, offered encouragement as well as feedback in both academic and daily life, helping me overcome the past years at Hanoi University of Pharmacy. Most importantly, I would like to dedicate my deepest gratitude to my family, who have always stood by, assisted, and motivated me from my earliest days. Finally, I would like to sincerely thank myself for the relentless efforts, enduring the countless exhausting days and nights, to reach this day. Hanoi, May 10th, 2025 Student Vu Thi Diem Quynh TABLE OF CONTENTS LIST OF SYMBOLS AND ABBREVIATIONS LIST OF TABLES LIST OF FIGURES AND CHARTS STATEMENT OF THE PROBLEM.
Overview of Ebastine. Chemical structure and physicochemical properties. Pharmacological and pharmacokinetic properties. Quantitative Methods for Ebastine.
Overview of dissolution testing for solid oral dosage forms. Dissolution test for solid dosage forms. Commonly used dissolution media. Significance of dissolution testing.
11 CHAPTER 2: MATERIALS AND METHODS. Materials, equipment and study samples. Materials, solvents, and chemicals. Equipment and instruments.
Development and validation of the dissolution test method for Ebastine dispersible tablets. Development and validation of the dissolution test method for Ebastine dispersible tablets. Data processing method .18 CHAPTER 3: RESULTS AND DISCUSSION. Development and validation of the dissolution test method for Ebastine dispersible tablets.
Preliminary investigation and method selection. Investigation and development of the analytical method. Analytical method validation. Dissolution test procedure for Ebastine 5 mg dispersible tablets.
On the selection of conditions and requirements for the dissolution test. On the selection of the analytical method for the post-dissolution samples 35 3. On the selection of the analytical mobile phase. On method validation .37 CHAPTER 4: CONCLUSIONS AND RECOMMENDATIONS.
39 REFERENCES APPENDICES LIST OF SYMBOLS AND ABBREVIATIONS Symbols/Abbreviations Full term ACN Acetonitrile AOAC Association of Official Analytical Chemists Apeak Peak area API(s) Active pharmaceutical ingredient(s) BP British Pharmacopoeia DAG Diacylglycerol DM Dissolution medium EP European Pharmacopoeia H1R(s) H1 Receptor(s) H3PO4 Phosphoric acid HCl Hydrochloric acid HPLC High-performance Liquid Chromatography IP3 Inositol 1,4,5-triphosphate IVIVC In Vitro-In Vivo Correlation JP Japanese Pharmacopoeia KH2PO4 Kali dihydrophosphate LogP Octanol-water partition coefficient MeOH Methanol MP Mobile phase Na2HPO4 Disodium hydrophosphate Na3PO4.12H2O Trisodium phosphate dodecahydrate NaCl Sodium chloride NaH2PO4 Sodium dihydrogen phosphate No. Number NTP Number of theoretical plates pKa Acid dissociation constant PLC Phospholipase C Ref. References RSD Relative standard deviation SDS or SLS Sodium dodecyl sulfate or Sodium lauryl sulfate Tf Tailing factor tR Retention time USP United States Pharmacopeia VP Vietnamese Pharmacopoeia LIST OF TABLES Table 1. Analytical methods related to the quantification of Ebastine.
Type and amount of enzyme for specific dissolution medium in USP. Dissolution medium described in JP. Dissolution medium described in BP, EP and VP. Components of Ebastine 5 mg dispersible tablet.
Preparation of Calibration Standards. Specificity Test Results of the UV-VIS Spectrophotometric Method. System suitability results. Calibration data of Ebastine.
Results of Repeatability and Intermediate Precision. Stability Investigation of Standard and Spiked Samples over 24 Hours. Results with changes in column temperature (40°C and 37°C). Dissolution Test Results of Ebastine 5 mg Dispersible Tablets .34 LIST OF FIGURES AND CHARTS Figure 1.
Structure of Ebastine. Metabolism of Ebastine to Carebastine. Mechanism of allergy. Simplified two-state model of H1 receptor.
Dissolution basket apparatus (a) and paddle apparatus (b). Simplified module of flow through cell apparatus. UV spectrum of Ebastine standard solution (a) and filtered placebo solution (b) in DM. UV spectrum of Ebastine standard solution in DM:MeOH 50:50.
Chromatogram of using MeOH:Water 80:20 as mobile phase. Chromatogram of using MeOH:Water 70:30 as mobile phase. Chromatogram of using MeOH:Water 65:35 as mobile phase. Chromatogram of using ACN:Water 70:30 as mobile phase.
Chromatogram of using ACN:Water 60:40 as mobile phase. Chromatogram of using ACN:Water 50:50 as mobile phase. Chromatogram of using ACN:Phosphate buffer (pH 3.5 as mobile phase. Chromatograms at flow rate 1.5 mL/min for the standard sample (a) and spiked sample (b).
Chromatograms of standard sample (a) and spiked sample (b) in 60 minutes analysis time. Chromatogram for specificity validation. UV spectrum of Ebastine in standard sample (a) and spiked sample (b). Overlay of UV spectrum of Ebastine in the standard and spiked samples.
The linear correlation between peak areas and Ebastine concentration. Comparison of the chromatograms of placebo and standard samples .36 STATEMENT OF THE PROBLEM In recent years, the issue of climate change, particularly the increase in emissions and fine dust, has led to a global rise in the incidence of allergic and hypersensitivity disorders. These conditions negatively impact on patients’ physical and mental health, consequently diminishing their quality of life as well as that of their families and the entire society [1]. This situation has created an urgent need for safe and effective antihistamine drugs.
Among them, Ebastine has demonstrated comparable efficacy with fewer adverse effects compared to other second-generation antihistamines, allowing patients to maintain daily activities [2], [3], [4]. As of 2024, the Vietnamese pharmaceutical market has issued registration certificates for 55 drugs and active pharmaceutical ingredients containing Ebastine, with 22 registrations of those granted in 2024 alone [5]. This increase underscores the necessity for improved quality control and safety monitoring of Ebastine-containing pharmaceutical products. Dispersible tablets offer high stability, accurate dose uniformity, and ease of administration, particularly for patients who have difficulty swallowing or who require rapid onset of therapeutic action [6].
Like other solid dosage forms, one crucial criteria for dispersible tablets is the evaluation of active pharmaceutical ingredient (API) release through dissolution testing, especially when the formulation contains APIs with poor water solubility characteristics like Ebastine. However, differences in materials and manufacturing processes among products can introduce variability in analytical outcomes. Therefore, the development of an appropriate dissolution testing method is essential to ensure accuracy and reliability in drug quality control. Establishing a standardized testing method plays an important role in ensuring consistency and quality among pharmaceutical products, thereby protecting public health and enhancing consumer confidence in domestically manufactured drugs.
Based on these practical needs and the importance of drug quality control, this thesis was conducted with the title “Development of a Dissolution Testing Method for Ebastine Dispersible Tablets”, with the following objectives: 1. To develop and validate a dissolution testing method for Ebastine dispersible tablets. To apply the developed method on Ebastine 5 mg dispersible tablets produced by the National Institute of Pharmaceutical Technology. Overview of Ebastine 1.
Chemical structure and physicochemical properties 1. Chemical structure Figure 1. Structure of Ebastine IUPAC name: 4-(4-benzhydryloxypiperidin-1-yl)-1-(4-tert-butylphenyl) butan-1-one ATC code: R06AX22 Molecular formula: C32H39NO2 Molecular weight: 469. Physicochemical properties Ebastine is white to almost white, crystalline powder, practically insoluble in water, sparingly soluble in methanol and chloroform.
Ebastine has the melting point of about 80-82°C, and its predicted boiling point is approximately 596.89 and pKa values in the range of 8. Pharmacological and pharmacokinetic properties 1. Mechanism and pharmacological effects Ebastine is a second-generation antihistamine with high selectivity for the H1 receptor (H1R). Once absorbed inside the body, Ebastine is metabolized into Carebastine – an active metabolite that blocks the action of histamine on H1Rs [9], [10].
Metabolism of Ebastine to Carebastine H1Rs are G-protein-coupled-receptors which activate signaling pathways upon coupling with Gq/11 proteins. This activation leads to an increased production of inositol 1,4,5-triphosphate (IP3) and diacylglycerol (DAG), resulting in several typical symptoms of allergic reactions, such as itching, smooth muscle spasm. Mechanism of allergy 3 Under normal conditions, H1Rs exist in an equilibrium between active and inactive states (a). In the presence of an agonist like histamine, it combines H1Rs, stabilizing them in their active conformation, thereby shifting the equilibrium towards the active state, which enhances allergic responses (b).
Conversely, in the presence of an inverse agonist, such as H1-antihistamines, the equilibrium shifts towards the inactive state, thereby inhibiting the production of allergic mediators (c) [11]. Simplified two-state model of H1 receptor 1. Pharmacokinetic properties Absorption: Ebastine is rapidly absorbed and undergoes first-pass metabolism immediately after oral administration to its active metabolite, Carebastine. Distribution: Peak plasma concentrations of Carebastine are reached approximately 3-6 hours after a single oral dose of Ebastine.
Steady-state concentrations are achieved after approximately 3-5 days with multiple-dose regimens, and the bioavailability of Carebastine is increased when Ebastine is administered with food. Carebastine is approximately 98% bound to plasma proteins and has a large volume of distribution (90-140 L). Metabolism: Ebastine is metabolized to Carebastine predominantly via cytochrome P450 isoenzymes such as CYP3A4, CYP2J2, and CYP4F12. Excretion: Carebastine is primarily excreted in the urine as conjugated metabolites (approximately 66%) and has an elimination half-life of approximately 13- 16 hours.
Hepatic or renal impairment significantly increases the biological half-life but 4 does not significantly affect bioavailability. Concomitant use with drugs metabolized by CYP3A4 may slow down its metabolism and reduce its excretion [9], [10]. Indications, Contraindications Indications: Ebastine is indicated for the symptomatic treatment of seasonal or perennial allergic rhinitis, allergic conjunctivitis, or chronic idiopathic urticaria. Precautions: Caution should be exercised in patients with abnormal electrocardiogram (ECG) findings, prolonged QT interval, or hypokalemia; patients using inhibitors of CYP450 (2J2, 4F12, 3A4) such as ketoconazole and macrolide antibiotics; patients with severe hepatic impairment; and in co-administration with imidazole antifungal agents, macrolide antibiotics, or rifampicin.
Contraindications: Ebastine is contraindicated in patients with hypersensitivity to any component of the drug product and in children under 12 years old, as its safety and efficacy in this age group have not yet been established. Quantitative Methods for Ebastine Table 1. Analytical methods related to the quantification of Ebastine Analytical No. Analytical purpose Operating conditions Ref.
method 1 Dissolution test of UV-VIS Spectro- Analytical wavelength: [12] Ebastine fast- photometry 252 nm disintegrating tablets 2 Dissolution test of UV-VIS Spectro- Analytical wavelength: [13] Ebastine fast- photometry 254 nm disintegrating tablets 3 Dissolution test of UV-VIS Spectro- Analytical wavelength: [14] Ebastine tablets photometry 257 nm 4 Dissolution test of UV-VIS Spectro- Analytical wavelength: [15], Ebastine tablets and photometry 258 nm [16] Ebastine Orally Disintegrating Tablets 5 Quantification of High Performance Column: 150 mm × 4.
