Stability Testing of Pharmaceutical Dispersions

oct 05 2018

Pharmaceutical products comprise strictly controlled ratios of inert carrier media to biologically active ingredients (AIs). The carrier is designed to act as a delivery method for the active ingredient to facilitate the drug’s therapeutic action with enhanced locality. Solid phase pharmaceuticals such as capsules and tablets are basic in terms of their target specificity. These drugs must be ingested before the AIs can permeate through the blood barrier, often with significant delays before any therapeutic action occurs.

Pharmaceutical dispersions typically exhibit enhanced target specificity and can be integrated into more efficient drug delivery systems compared to solid products. The drawback of this arrangement is that dispersions are more likely to present physical instabilities than solid powders. Injectables, vaccines, lotions, and inhalants are therefore subject to stricter stability testing for quality control and quality assurance.

This blog post will explore the importance of stability testing for pharmaceutical dispersions.

Outlining Stability Testing

Stability testing of pharmaceutical colloids is carried out to determine the lifespan of a product and determine how its behavior changes over time. The chemical and mechanical characteristics of pharmaceutical dispersions are key for characterizing their tendency towards particle migration aggregation or other particle size evolution. These physical instabilities can irreversibly and drastically affect the efficacy of drugs in the dosage form.

Since the targetability of drug delivery systems is rapidly improving, emulsions and nanoparticle suspensions are now widely employed in therapeutic applications. Tissue-specific targeting and potentially cytotoxic drug-delivery systems have been explored in recent years, using novel emulsions and nanoparticle suspensions.

These new and emerging medicines must be characterized through robust stability testing to ensure that colloidal systems display suitable stability over time, for example, the particle remains in nanoscale during the lifespan of the dispersion.

Stability Testing with Formulaction

TURBISCAN® is a unique stability testing technology engineered to provide accelerated aging tests of pharmaceutical dispersions in unstressed states. This novel method uses static-multiple light scattering (S-MLS) to determine the long-term integrity of dispersions under accurately simulated conditions. Alternative technologies introduce thermal or mechanical stress (dilution or centrifugation) to accelerate the aging process of products under test, but this often causes instabilities that are not reflective of the end-products conditions.

The TURBISCAN® range of analyzers provides true stability testing for accurate analysis of pharmaceutical dispersions at rest, without dilution. Multiple light scattering provides ultra-precise detection of colloidal instability, providing quantitative data regarding distinct dispersive phenomena such as agglomeration, aggregation, and sedimentation. This can be performed at pressure to measure highly concentrated dispersions and vapor-phase inhalants.

The unique software provides a simple calculation of the dispersion’s stability as the Turbiscan Stability Index, providing rapid indexing of the colloid’s long-term mechanical behavior.

If you would like any more information about performing stability testing with Formulaction, please do not hesitate to contact us.

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