The commercial and scientific success of a pharma product can only be ensured with the knowledge of the drug development process and the innumerable milestones and tasks that are essential to a complete development plan. To determine the potency, purity, and identity of these pharma products, stability testing is essential.

The stability of pharma products is the capability of a formulation in a specific environment and remain within its physical, therapeutic, microbiological, chemical, and toxicological specification. The stability studies of pharma products ensure the upkeep of product efficacy, safety, and quality throughout their life. Stability Testing is a complex process because of the involvement of several factors such as the interaction between active ingredients and excipients, type of dosage form, the stability of active ingredients, and container used for packaging.

Types of Stability Testing 

There are three major types of stability testing carried out at different stages of product development. Early-stage stability testing is carried out to determine the type of degradation products that may be found after long-term storage. Here are some of the common types:

  • Real-time Stability Testing: This is often carried out for a longer duration to allow major product degradation under suggested storage conditions. The test period depends on the stability of the product which must be long enough to specify clearly that no quantifiable degradation takes place and allows one to differentiate degradation from inter-assay variation.
  • Cyclic Temperature Stability Testing: Cyclic testing is not a routine method for marketed products. Here, the temperature tests are carried out based on the knowledge of the product to stimulate similar conditions in the marketplace where they will be kept. The maximum and minimum temperatures for stress testing must be chosen on a product-by-product basis and taking into consideration factors such as product storage temperatures and physical and chemical degradation of the product.
  • Accelerated Stability Testing: In this procedure, a product is stressed at multiple high temperatures and the heat input needed to cause product failure is established. This is carried out to subject the product to a condition that hastens degradation. The information gained is subsequently projected to forecast the shelf life or to compare the relative stability of alternate formulations.
  • Retained Sample/Ongoing Stability Testing: Retained stability testing is a practice for every marketed product for which stability data are needed.

Once a pharma product is registered, additional stability studies are needed if there are any variations. Such variations affect the stability of active pharmaceutical substances. Some of these variations include a change in the manufacturing process, immediate packaging, and the composition of the pharma product.

Need for Good Manufacturing Practices Stability Study

GMP Stability studies are needed because of the following reasons:

  • Safety point of view of patients
  • Determine container suitability
  • Ascertain recommended storage questions
  • Determine product shelf-life.
  • Offer proof as to how product quality fluctuates with time.

Stability Testing Guidelines

Stability testing guidelines consist of issues associated with stability data requirements for application dossier and the steps needed for execution. Such guidelines were issued in 1980. The World Health Organization (WHO), modified the guidelines set by the International Conference on Harmonization (ICH) as they did not address the climatic conditions found in several countries.

Stability guidelines offer storage conditions and times for intermediate, long-term, and accelerated stability studies. Some of the general storage conditions are as follows:

  • 40°C/75% Relative Humidity (RH)
  • 30°C/65% RH
  • 25°C/60% RH

Stability testing is the key practical component in the pharma development program for new drugs and formulation. Stability tests are done so that the proposed shelf life and storage conditions can be incorporated in the tag to guarantee that the drug is reliable and effective during its shelf life. Over time and with growing attention and experience, regulatory requirements are becoming increasingly stringent to accomplish the goals in all possible conditions.