Stability Testing

Demonstrating Stability

Broadly, pharmaceutical manufacturers must be primarily concerned with five general stability types.
1 of


All active ingredients, key additives, and excipients retain their chemical integrity and labeled potency within the specified limits.


Product retains its original physical properties, including appearance, palatability, uniformity, dissolution, and suspendability.


Product retains its sterility or resistance to microbial growth; any incorporated antimicrobial agents retain effectiveness within the specified limits.


The therapeutic effect is unchanged throughout the product’s specified life.


No significant increase in toxicity.

Stability Testing Guidance

Stability Testing Services

Storage Conditions

Standard: ICH Q1A(R2)

A drug substance must be evaluated under storage conditions to test its thermal stability and, if applicable, its sensitivity to moisture. The storage conditions and study lengths should be sufficient to cover the storage, shipment, and subsequent use. Generally, a long term storage study will be at least 12 months, and intermediate and accelerated studies, approximately six months.

Forced Degradation

Standard:  ICH Guideline Q1B

Forced degradation studies allow pharmaceutical developers and manufacturers to understand the degradation pathways of drug substances and products. These experiments expose the material(s) to external stressors like heat, light, acid, base, and oxidation to assess the stability of the components or end product.

Freeze-Thaw / Thermal Stress Testing

Standard: Referenced within ICH Q1F

Freeze-thaw studies inflict a series of extreme temperature changes on a drug product. The sample is then analyzed for impacts on its integrity and therapeutic effectiveness.


Standard: ICH Guideline Q1B

Photostability studies evaluate drug substances to ensure that exposure to light does not result in unacceptable product degradation or other unacceptable changes.

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