stability and packaging

Understanding Stability in Medicines

  • Definition of Stability:

    • Relative concept depending on:

    • Inherent stability of the active pharmaceutical ingredient (API)

    • Stability of excipients

    • Dosage form structure

    • Protectiveness of container closure system

    • Recommended storage conditions

    • Sources: Aulton & Taylor, Pharmaceutics 5th edition

  • Factors Influencing Stability:

    • API: Characteristic stability

    • Excipients: Functionality in formulations

    • Processing: Techniques impacting drug formulation

    • Packaging: Container material properties

    • Storage Conditions: Environmental factors affecting stability

Types of Chemical Instability

  • Oxidation: Breakdown due to reactions with oxygen

  • Hydrolysis: Breakdown due to reactions with water

  • Photodegradation: Decomposition due to light exposure

  • Isomerisation/Polymerisation: Structural rearrangement and combining molecules

  • Formation of Adducts and Complexes: Unintended connections affecting efficacy

  • Polymorphic Changes: Transition between different forms affecting solubility

Types of Physical Instability

  • Suspension Redispersibility/Resuspension: Stability issues in liquid forms

  • Appearance and Dissolution: Visual characteristics affecting acceptability

  • Precipitation and Particle Size: Solid phase separation impacting dosage uniformity

  • Rheology: Flow properties affecting dosage form

  • Water Content: Moisture levels affecting solubility and stability

Other Instabilities Related to Packaging

  • Adsorption: Components adhering to package interior

  • Absorption: Materials being absorbed from the package

  • Leaching: Leaching of package materials into the product

  • Microbiological Issues: Contamination risks if not properly preserved

Assessing Stability During Development

  • Preformulation Studies: Initial assessments of active stability

  • Stress Testing: Assessing under extreme conditions to identify degradation paths

  • Formulation Development: Creation of optimal drug combinations for increased stability

  • Post-Authorization Studies: Long-term stability monitoring after market release

Guidelines for Stability Testing

  • International guidelines (ICH):

    • Q1A (R2): Stability testing of New Drug substances and products

    • Q1B: Photostability Testing

    • Q1C: Stability Testing for New Dosage Forms

    • Q1E: Evaluation of Stability Data

    • Q5C: Stability Testing of Biotechnological/Biological Products

Creating Expiry Dates

  • Shelf-life Requirements: Must contain ≥ 95% of label claim at expiry

  • Overages: Limited ability to account for degradation in formulations

  • Temperature Stability Data: Transformed using the Arrhenius Equation to anticipate shelf life

Reasons for Packaging Medicinal Products

  • Product Identity: Ensuring the right product is delivered

  • Protection: Shielding from environmental factors

  • Patient Compliance: Ease of use and accessibility

  • Presentation: Clear information and instructions for use

  • Tamper Protection: Ensuring consumer safety

Types of Primary and Secondary Packaging

  • Primary Packaging: Directly contains the drug

    • Examples: Bottles (glass, plastic), tubes, jars

    • Material Types: Glass (moisture resistance), metal (light protection), plastics (flexibility)

  • Secondary Packaging: Outer cartons for protection during transport

    • Includes patient information leaflets and additional labeling.

Sealing and Filling Methods

  • Sealing Techniques: Screw caps, push-on lids, heat seals for ampoules

  • Filling Methods:

    • Volumetric Filling: Using pumps or cylinders

    • Weigh Filling: Ensuring accurate dosing by weight

Integrity Testing and Common Problems

  • Integrity Testing: Regular checks during the manufacturing process for leaks or contamination

  • Common Issues:

    • Banana shaping due to material stress

    • Distortion in blisters leading to product damage

Labelling: Methods and Types

  • Variable Data Printing: Batch numbers, expiry dates

  • Labelling Methods: Roll-on, pick-and-place for precise application

  • Types of Labels: Partial or total wraparound, panel labels for larger containers therefore ensuring thorough information transfer to consumers.

Quality Assessment in Packaging

  • Ensuring compliance with quality control measures including:

    • Labeling accuracy

    • Sterility in sterile products

    • Correct quantity and absence of particulates or damage

  • Continuous monitoring of the packaging process to ensure a high standard at all times.