Fasttrack Pharmaceutics

Pharmaceutics – Dosage Form and Design Pharmaceutics – Dosage Form and Design David Jones Chair of Biomaterial Science, School of Pharmacy, Queen’s University of Belfast, UK Pharmaceutical Press London ● Chicago Dedicated to my mother May, my late father Fred, my wife Linda and our children Dary and Holly. Published by the Pharmaceutical Press An imprint of RPS Publishing 1 Lambeth High Street, London SE1 7JN, UK 100 South Atkinson Road, Suite 206, Grayslake, IL 60030-7820, USA © Pharmaceutical Press 2008 is a trade mark of RPS Publishing RPS Publishing is the wholly owned publishing organisation of the Royal Pharmaceutical Society of Great Britain First published 2008 Typeset by J&L Composition Ltd, Filey, North Yorkshire Printed in Great Britain by TJ International, Padstow, Cornwall ISBN 978 0 85369 764 0 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the copyright holder. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. The right of David Jones to be identified as the author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act, 1988. A catalogue record for this book is available from the British Library. Contents Introduction to the FASTtrack series vii 4. Pharmaceutical disperse systems 3: Preface viii ointments, pastes, lotions, gels and related formulations. 75 About the author x Introduction 75 Advantages and disadvantages of 1. Pharmaceutical solutions for oral pharmaceutical ointments, pastes, administration . 1 lotions, liniments, collodions and gels 76 General description 1 Pharmaceutical ointments and pastes 77 Advantages and disadvantages of Pharmaceutical lotions, liniments, pharmaceutical solutions for oral collodions and paints 86 administration 2 Pharmaceutical gels 88 Drug solubility 2 Multiple choice questions 99 Excipients used in pharmaceutical solutions for oral administration 6 5. Parenteral formulations . 103 Types of pharmaceutical solutions 15 General description 103 Multiple choice questions 21 Routes of parenteral administration 103 Advantages and disadvantages of 2. Pharmaceutical disperse systems 1: parenteral formulations 106 suspensions – general principles and Formulation considerations for the formulation of suspensions for oral parenteral formulations 108 administration . 25 Surface-active agents 115 General description 25 Multiple choice questions 131 Advantages and disadvantages of pharmaceutical suspensions 26 6. Ocular, nasal and otic dosage forms. 135 The physical stability of pharmaceutical suspensions 27 Introduction 135 Formulation considerations for orally Advantages and disadvantages of administered suspension formulations 33 ocular dosage forms 136 Excipients used in the formulation of Administration of therapeutic agents suspensions for oral administration 35 to the eye 137 Multiple choice questions 42 Nasal formulations 150 Otic formulations 152 3. Pharmaceutical disperse systems 2: Multiple choice questions 154 emulsions and creams . 45 General description 45 7. Vaginal and rectal dosage forms . 157 Advantages and disadvantages of Introduction 157 pharmaceutical emulsions 46 Rectal dosage forms 157 Emulsion instability and theories of Vaginal dosage forms 174 emulsification 47 Multiple choice questions 177 Formulation of pharmaceutical emulsions 55 Excipients used in pharmaceutical 8. Respiratory dosage forms . 181 emulsions 65 Introduction 181 Manufacture of emulsions 70 Advantages and disadvantages of Multiple choice questions 70 respiratory drug delivery 181 v vi Contents Physiology of the respiratory tract 182 Coating of tablets 244 Factors affecting the deposition of Multiple choice questions 251 particles/droplets within the respiratory tract 184 Mechanisms of particle deposition 10. Solid-dosage forms 2: capsules . 255 within the respiratory tract 185 Introduction 255 Formulation of respiratory dosage forms 187 Advantages and disadvantages of Multiple choice questions 199 capsule formulations 256 Materials and manufacture of capsules 256 9. Solid-dosage forms 1: tablets . 203 Formulation considerations for hard Introduction 203 gelatin capsules 260 Advantages and disadvantages of Soft gelatin capsules 266 tablets as dosage forms 209 Multiple choice questions 270 Manufacture of tablets 210 Tablet defects 243 Postprocessing effects on tablet Multiple choice answers 273 properties 243 Index 276 Introduction to the series FASTtrack is a new series of study guides created for undergraduate pharmacy students. The books are intended to be used in conjunction with textbooks and reference books as an aid to revision to help guide students through their exams. They provide essential information required in each particular subject area. The books will also be useful for pre-registration trainees preparing for the Royal Pharmaceutical Society of Great Britain’s (RPSGB’s) registration examination, and to practising pharmacists as a quick reference text. The content of each title focuses on what pharmacy students really need to know in order to pass exams. Features include*: ■ concise bulleted information ■ key points ■ tips for the student ■ multiple choice questions (MCQs) and worked examples ■ case studies ■ simple diagrams. The titles in the FASTtrack series reflect the full spectrum of modules for the undergraduate pharmacy degree. Current and future titles include: Applied Pharmaceutical Practice Complementary and Alternative Medicines Pharmaceutical Compounding and Dispensing Pharmaceutics – Dosage Form and Design Pharmaceutics – Drug Delivery and Targeting Pharmacology Physical Pharmacy (based on Florence & Attwood’s Physicochemical Principles of Pharmacy) Managing Symptoms in the Pharmacy Therapeutics There is also an accompanying website which includes extra MCQs, further title information and sample content: www.fasttrackpharmacy.com. If you have any feedback regarding this series, please contact us at [email protected]. *Note: not all features are in every title in the series. vii Preface Pharmaceutical formulation involves the rational design and manufacture of dosage forms to ensure that the required biological and physical performances of the therapeutic agent are attained. The formulation scientist is therefore expected to have knowledge of several scientific disciplines, including physical pharmaceutics, pharmaceutical chemistry and biopharmaceutics. Pharmaceutical formulation may therefore be correctly viewed as an essential and unique component of the pharmaceutical sciences and, accordingly, the Pharmacy undergraduate degree. Due to the interdisciplinary nature, pharmaceutical formulation is often considered difficult by many students and challenging to all students. This textbook aims to ease the perceived difficulties of this subject and, hopefully, illustrate the significance of pharmaceutical formulation and the unique role of the pharmacist in the development of medicines. The contents of this text have been designed to cover the vast majority of dosage forms that graduate pharmacists will encounter when they enter professional practice. In particular, the text aims to deliver the essential information concerning the formulation of these dosage forms in a format that will hopefully aid the understanding and hence remove the complexities of the various topics. The reader will observe that, in addition to the required theoretical aspects, each chapter contains information regarding the types (and physicochemical properties) of excipients that are used in the formulation of dosage forms. It is the author’s opinion that this information is essential to ensure that the reader is able to traverse the information gap between the theory and practice of dosage form design. In understanding the physicochemical properties of excipients (and indeed therapeutic agents), the student will be able to optimise the prepared dosage form and, in addition, will be able to answer examination questions with the appropriate depth required to attain a high grade. Each chapter describes a category of dosage form and, whilst the exact details change, it may be observed that the format of the chapters is similar. This will assist students in understanding and recalling the required information. The formulations of liquids and suspensions for oral administration, including the required theoretical aspects, are presented in Chapters 1 and 2. In Chapters 3 and 4 the theoretical aspects and formulations of products that contain disperse phases are described. Whilst these products are mostly administered topically, the formulation of emulsions for oral administration is also described. Chapter 5 describes parenteral formulations and, in particular, illustrates strategies for the successful formulation of parenteral solutions, suspensions and emulsions (including the considerations of osmolality and sterility and methods to attain sterility). viii Preface ix The formulation of ocular (and related) dosage forms is described in Chapter 6. In addition to the description of ocular formulations, this chapter concisely describes the biological demands of these formulations and, in so doing, highlights the effects of formulation type on the biological performance of the preparation. Chapter 7 examines the formulation of suppositories

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