Drug Stability for Pharmaceutical Scientists


  • Thorsteinn Loftsson, MS Pharm, MSc, PhD, Faculty of Pharmaceutical Sciences, Professor of Physical Pharmacy, University of Iceland, Reykjavik, Iceland

Drug Stability for Pharmaceutical Scientists is a clear and easy-to-follow guide on drug degradation in pharmaceutical formulation. This book features valuable content on both aqueous and solid drug solutions, the stability of proteins and peptides, acid-base catalyzed and solvent catalyzed reactions, how drug formulation can influence drug stability, the influence of external factors on reaction rates and much more. Full of examples of real-life formulation problems and step-by-step calculations, this book is the ideal resource for graduate students, as well as scientists in the pharmaceutical and related industries.
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The book is intended for graduate students taking courses in physical pharmacy or drug stability as well as for pharmaceutical scientists in industry (drug formulators, drug registration etc.) and for individuals working in related fields (e.g. cosmetics).


Book information

  • Published: January 2013
  • ISBN: 978-0-12-411548-4

Table of Contents

I. Principles of drug degradation (the solution kinetics and mathematical treatment):
1. Zero, first, second and third order reactions
2. Complex reactions (e.g. reversible reactions, parallel reactions, consecutive reactions, steady state, enzyme kinetics etc.)
3. Effect of temperature (e.g. Arrhenius, Q10-values, Collision theory, Transition state theory, Eyring equation etc.)
4. Effect of pH (Specific acid/base catalysis, pH-rate profiles)
5. Effect of buffer salts (General acid/base catalysis or buffer catalysis)
6. Ionic strength
7. Solvent effects (e.g. dielectric constant)
8. Surface active compounds (micelle effect)
9. Effect of complexation (e.g. cyclodextrins, metal ions and carbohydrates)
10. Effect of light, oxygen and other catalytic compounds.
II. Degradation pathways
Selected examples of drug degradation with examples and mathematical calculations.
1. Hydrolysis (aspirin, procaine, procainamide, acetaminophen, β-lactam antibiotics, nitrogen mustards etc.)
2. Oxidation (morphine, epinephrine, vitamin C, vitamin A, hydrocortisone, polyunsaturated fatty acids (autoxidation) etc.; antioxidants)
3. Isomerization and racemization (ephedrine, tetracyclines, pilocarpine, vitamin A, thalidomide, etc.)
4. Photodegradation
5. Polymerization (β-lactam antibiotics etc.)
6. Decarboxylation and elimination (p-aminosalicylic acid)
7. Dehydration (prostaglandins etc.)
III. Drug degradation in semi-solid state
1. Ointments
2. Creams (o/w and w/o emulsions)
3. Gels
IV. Drug degradation in solid state
1. Physical stability of drugs (crystallization of amorphous drugs, polymorph transitions, crystal growth, moisture absorption and vapor absorption, nitroglycerine)
2. Chemical stability (hydrolysis (aspirin), etc.)
V. Stability of peptide and proteins
VI. Stability testing
1. Stability testing during preformulation studies.
2. Stability testing of the final product
3. Regulations of stability testing (including ICH guidelines)