Introduction to Pharmaceutical Analytical Chemistry

Stig Pedersen-Bjergaard, Bente Gammelgaard, Trine G. Halvorsen

• Publisher: Wiley
• Year: 2019
• ISBN:
  9781119362753
• Edition: 2
• Topic: Physical Sciences
• Subtopic: Analytic Chemistry

The definitive textbook on the chemical analysis of pharmaceutical drugs ­– fully revised and updated

Introduction to Pharmaceutical Analytical Chemistry enables students to gain fundamental knowledge of the vital concepts, techniques and applications of the chemical analysis of pharmaceutical ingredients, final pharmaceutical products and drug substances in biological fluids. A unique emphasis on pharmaceutical laboratory practices, such as sample preparation and separation techniques, provides an efficient and practical educational framework for undergraduate studies in areas such as pharmaceutical sciences, analytical chemistry and forensic analysis. Suitable for foundational courses, this essential undergraduate text introduces the common analytical methods used in quantitative and qualitative chemical analysis of pharmaceuticals.

This extensively revised second edition includes a new chapter on chemical analysis of biopharmaceuticals, which includes discussions on identification, purity testing and assay of peptide and protein-based formulations. Also new to this edition are improved colour illustrations and tables, a streamlined chapter structure and text revised for increased clarity and comprehension.

• Introduces the fundamental concepts of pharmaceutical analytical chemistry and statistics
• Presents a systematic investigation of pharmaceutical applications absent from other textbooks on the subject
• Examines various analytical techniques commonly used in pharmaceutical laboratories
• Provides practice problems, up-to-date practical examples and detailed illustrations
• Includes updated content aligned with the current European and United States Pharmacopeia regulations and guidelines

Covering the analytical techniques and concepts necessary for pharmaceutical analytical chemistry, Introduction to Pharmaceutical Analytical Chemistry is ideally suited for students of chemical and pharmaceutical sciences as well as analytical chemists transitioning into the field of pharmaceutical analytical chemistry.

1
Introduction to Pharmaceutical Analytical Chemistry

1. 1.1 Introduction
2. 1.2 Pharmaceutical Analytical Chemistry
   1. 1.2.1 A Brief Definition
   2. 1.2.2 Manufacture of Pharmaceuticals
   3. 1.2.3 Development of New Drugs
   4. 1.2.4 Use of Pharmaceuticals
3. 1.3 This Textbook

1.1 Introduction

In daily conversation, words like pills and drugs are typically in use. However, when entering the pharmaceutical world, wording becomes very important and correct terms should be used. A pharmaceutical preparation contains a substance that is pharmacologically active, which is called the active pharmaceutical ingredient (or active ingredient). The active pharmaceutical ingredient is often abbreviated to API. A large number of APIs exists and two examples are shown in Figure 1.1, namely paracetamol (acetaminophen), which is used against pain, and insulin aspart, which is used in the treatment of diabetes. Paracetamol is a small molecule API (or small molecule drug) produced by organic synthesis and with a molecular mass of 151 Da. Insulin aspart, on the other hand, is a two‐chain peptide produced by recombinant DNA technology. It is a large molecule drug with a molecular mass of 5826 Da and is termed a biopharmaceutical due to its biological origin.

Figure 1.1 Paracetamol (small molecule drug) and insulin aspart (biopharmaceutical)

An active ingredient is not given (administered) to the patient as a pure substance, but is combined with excipients (synonymous with inactive ingredients) into a dosage form in order to be able to give an exact dose to the patient. The excipients are not pharmacologically active. The dosage form can be a tablet, a capsule, or a syrup for oral administration, an injection for parenteral administration, or an ointment for topical administration. The excipients used in pharmaceutical preparations serve several functions, and these can be summarized as follows:

• Ensure that the dosage form has a shape and size that is easy to use for the patient.
• Ensure that the API is released and delivered to the patient in the correct amount.
• Ensure that the pharmaceutical preparation has an acceptable stability.
• Ensure that the pharmaceutical preparation does not have an unpleasant taste or odour.
• Facilitate production of the pharmaceutical preparation.

The excipients vary widely for different preparations. To exemplify this, Table 1.1 shows the excipients of tablets and syrup containing paracetamol as the active ingredient. Paracetamol has both an analgesic and an antipyretic effect, which means that it is used against pain and fever. Each paracetamol tablet has a total mass of 285 mg. Paracetamol constitutes 250 mg, while the remaining 35 mg is made up of excipients. The excipients include a disintegrating agent, a lubricant, a glidant, and a binder. Binders, lubricating agents, and gliding agents are added to facilitate manufacture. The disintegrating agent ensures rapid disintegration of the tablet in the stomach of the patient and rapid release of paracetamol.

Table 1.1 Excipients in paracetamol tablets and paracetamol syrup (example)

Content	Amount (mg)	Function
Tablet (mass 285 mg)
Paracetamol	250	Active ingredient
Hydroxypropyl cellulose		Binder
Maize starch		Disintegrant
Talcum		Glidant
Magnesium stearate		Lubricant
Syrup (volume 1 mL)
Paracetamol	24	Active ingredient
Sorbitol		Sweetener
Glycerol		Sweetener
Polyvinylpyrrolidone		Thickening agent
Saccharine sodium salt		Sweetener
Methylparaben		Preservative
Ethylparaben		Preservative
Propylparaben		Preservative
Sodium metabisulfite		Antioxidant
Citric acid		pH regulator
Sodium citrate		pH regulator
Strawberry aroma		Flavouring agent
Water		Solvent

Paracetamol syrup (liquid preparation) is a 24 mg/ mL solution of paracetamol in water. In addition, several excipients are added. Sweetening and fl...

Table of contents

• Table of Contents
• Preface to the Second Edition
• Abbreviations
• Symbols and Units
• 1 Introduction to Pharmaceutical Analytical Chemistry
• 2 Marketing Authorizations, Pharmaceutical Manufacturing, and International Pharmacopoeias
• 3 Fundamentals of Bases, Acids, Solubility, Polarity, Partition, and Stereochemistry
• 4 Fundamentals of Pharmaceutical Analytical Chemistry
• 5 Titration
• 6 Introduction to Spectroscopic Methods
• 7 UV‐Vis Spectrophotometry
• 8 IR Spectrophotometry
• 9 Atomic Spectrometry
• 10 Introduction to Chromatography
• 11 Separation Principles in Liquid Chromatography
• 12 High Performance Liquid Chromatography
• 13 Gas Chromatography
• 14 Electrophoretic Methods
• 15 Mass Spectrometry
• 16 Sample Preparation
• 17 Quality of Analytical Data and Validation
• 18 Chemical Analysis of Pharmaceutical Ingredients
• 19 Chemical Analysis of Pharmaceutical Preparations
• 20 Bioanalysis Chemical Analysis of Pharmaceuticals in Biological Fluids
• 21 Chemical Analysis of Biopharmaceuticals
• Index
• End User License Agreement