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Drug stability


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Drug stability

  1. 1. Drug stability Under the guidance of RAMESH BABU.J M.Pharm,Sr.assiatant professor By WILWIN
  2. 2. CONTENTS 1) Definition 2) Adverse effects of drug instability 3) Factors affecting drug stability 4) Types of drug degradation 5) Types of stability studies 6) Methods of accelerated stability testing in dosage forms 7) Temperature and humidity control
  3. 3. Drug stabilty:It is the capacity of a drug product to remain with in specifications established to ensure its identity ,strength ,quality and purity. Adverse effects of instability of drugs  Loss of active drug (e.g. aspirin hydrolysis, oxidation of adrenaline).  Loss of vehicle (e.g. evaporation of water from o/w creams, evaporation of alcohol from alcoholic mixtures).  Loss of content uniformity (e.g. creaming of emulsions, impaction of suspensions).  Loss of elegance (e.g. fading of tablets and coloured solutions).  Reduction in bioavailability (e.g. ageing of tablets resulting in a change in dissolution profile).  Production of potential toxic materials (e.g. breakdown products from drug degradation).
  4. 4. Factors Affecting Stability Environmental factors Microbial contamination Containers and closure
  5. 5. Environmental factors Temperature light Moisture
  6. 6. Temperature  3 types of storage temperatures temperature 2.cold temperature 3.Freeze storage 1.Room temperature:  Upto 30/25o c 2.Cold temperature/Refrigerator storage:  Upto 2-8o c 3.Freeze storage:  Storage between -20 to -10o c
  7. 7. Light(photolysis)  the shorter the wavelength more the energy is absorbed per mole It means: decomposition by light  Various sources of light are sunlight, metal halide lamps, fluorescent lamps, or other indoor lighting sources.  These reactions can be induced by exposure to photolysis sources emitting in the 290–800 nm region.
  8. 8.  Relationship between wavelength and associated energy of various forms of light. Type of Wavelength radiation: board outers U.V. Visible I.r. Energy Kcal mol-1 50 – 400 400 – 750 750 – 10,000 287 – 72 36 - 1
  9. 9. Photolysis is prevented by:  Suitable packing in amber couloured bottles  Card board outers  Aluminum foil wrappers MOISTURE  It enhances the hydrolytic degradation  Packing materials such as Glass and Plastic are usually chosen to prevent exposure of drug product to high humid conditions
  10. 10. Microbial Instability Sources of microbial contamination Water gram-negative groups: Pseudomonas, Xanthamonas, Flavobacterium Air Mould spores: Penicillium, Aspergillus Bacterial spores: Bacillus spp. Yeasts Raw materials Starches Pigments Micrococci Coliforms Salmonella
  11. 11. Sources of Microbial Contamination Gums Animal products Actinomyces Salmonella, Coliforms Personnel Coliforms, Staphylococci, Sterptococci
  12. 12. Packaging And Stability 1.Glass  Glass is resistant to chemical and physical change and is the most commonly used material. Limitations 1. Its alkaline surface Overcome use of Borosilicate glass 2. Ions may precipitate the use of buffers insoluble crystals from the glass 3- Permits the transmission of light which may accelerate decomposition. Amber coloured glass
  13. 13. Packing and Stability 2.PLASTICS The problems with plastic are:  Migration of the drug through the plastic into the environment.  Transfer of environmental moisture, oxygen, and other elements into the pharmaceutical product.  Leaching of container ingredients into the drug.  Adsorption of the active drug or excipients by the plastic.
  14. 14. Packing and Stability 3.Metals  Various alloys and aluminum tubes may be utilized as containers for emulsions, ointments, creams and pastes.  Limitation: They may cause corrosion and precipitation in the drug product.  Overcome: Coating the tubes with polymers may reduce these tendencies.
  15. 15. Packing and Stability Rubber  Rubber also has the problems of extraction of drug ingredients and leaching of container ingredients.  The pretreatment of rubber vial stoppers and closures with water and steam reduces potential leaching.
  16. 16. Types of degradations Chemical Physical Biological
  17. 17. Chemical Degradation 1- Hydrolysis: Hydrolysis means “splitting by water’’
  18. 18. Some functional groups subject to Hydrolysis Drug type Examples Esters Aspirin, alkaloids Dexmethasne sodium phosphate Nitroglycerin Lactones Pilocarpine Spironolactone Amides Chloramphenicol Imides Glutethimide Malonic ureas Barbiturates
  19. 19. Chemical Stability 2- Oxidation Oxidation of inorganic and organic compounds is explained by a loss of electrons and the loss of a molecule of hydrogen. 3-Photolysis
  20. 20. Physical Stability Physical stability implies that:  The formulation is totally unchanged throughout its shelf life and has not suffered any changes by way of appearance, organoleptic brittleness, particle size etc.  It is significant as it affects: 1.pharmaceutical elegance 2.drug content uniformity 3.drug release rate. properties, hardness,
  21. 21. Physical Stability Formulation Likely physical instability problems Oral solutions 1- Loss of flavor 2- Change in taste 3- Presence of off flavors due to interaction with plastic bottle 4- Loss of dye 5- Precipitation 6- discoloration Effects Change in smell or feel or taste
  22. 22. Formulation Parenteral solutions Likely physical instability problems 1. Discoloration due to photo chemical reaction or oxidation 2. Presence of precipitate due to interaction with container or stopper 3. Presence of “whiskers” 4. Clouds due to: (i) Chemical changes (ii) The original preparation of a supersaturated Effects Change in appearance and in bio-availability
  23. 23. Physical stability Formulation Suspensions Likely physical instability problems 1- settling 2- caking 3- crystal growth Effects 1-Loss of drug content uniformity in different doses from the bottle 2- loss of elegance.
  24. 24. Physical stability Formulation Emulsions Likely physical Effects instability problems 1- Creaming 1- Loss of drug 2- coalescence content uniformity in different doses from the bottle 2- loss of elegance
  25. 25. Physical stability
  26. 26. Physical stability Formulation Semisolids (Ointments and suppositories) Likely physical Effects instability problems 1. Changes in: 1-Loss of drug a) Particle size content uniformity b) Consistency 2. Caking or coalescence 2- loss of elegance 3. Bleeding 3-change in drug release rate.
  27. 27. Physical stability Formulation Tablets Likely physical instability problems Effects Change in: Change in drug release a) Disintegration time b) Dissolution profile c) Hardness d) Appearance (soft and ugly or become very hard)
  28. 28. Physical stability Formulation Capsules Likely physical instability problems Change in: a) Appearance b) Dissolution c) Strength Effects Change in drug release
  29. 29. Types of Stability Studies 1.Long-Term (Real-Time) Stability Testing  Stability evaluation of the physical, chemical, biological and microbiological characteristics of a drug product  duration of the shelf life
  30. 30. Accelerated stability Testing  Studies designed to increase the rate of chemical degradation or physical change(s) of a drug product by using exaggerated storage conditions with the purpose of monitoring degradation reactions.  To evaluate the impact of short term excursions and predicting the shelf-life under normal storage studies may include conditions.  The design of accelerated elevated temperature, high humidity and intense light.
  31. 31. Methods Of Accelerated Stability Testing In Dosage forms  Freeze Thaw test  Centrifugal Test  Shaking test  Elevated Temperature test
  32. 32. Temperature and humidity control General storage conditions study Storage Conditions Minimum Time Period at Submission Long term 25 ± 2°C / 60% RH ± 5% Zone I,II. 30 ± 2°C / 35% RH ± 5% Zone III. 30 ± 2°C / 60% RH ± 5% Zone IV. 6 Months 6 Months 6 Months Intermediate 30 ± 2°C / 60% RH ± 5% 6 Months Accelerated 40 ± 2°C / 75 % RH ± 5% 6 Months
  33. 33. Products packed in semipermeable containers. Study Storage Conditions Minimum Time Period at Submission Long term 25 ± 2°C / 40% RH ± 5% zone I,II 6 Months Long term 30 ± 2 ºC/ 60% RH ± 5% zone III,IV 6 Months Intermediate 30 ± 2°C / 60% RH ± 5% 6 Months Accelerated 40 ± 2°C / NMT 25% RH 6 Months
  34. 34. Products intended for storage in a Refrigerator Study Storage Conditions Minimum Time Period at Submission Long term 5 ± 3°C 6 Months Accelerated 25 ± 2°C / 60% RH ± 5% 6 Months
  35. 35. Products intended for storage in a freezer Study Storage Conditions Minimum Time Period at Submission Long term -20 ± 5°C 12 Months