Inhalation Drug Stability Studies

As drug inhalation is growing in popularity for local and systemic therapies, laboratory testing of inhaled products is becoming increasingly valuable in determining their safety and efficacy. Stability studies play an important role in inhalation development, arguably more so than other delivery systems. As well as the chemical stability of the active drug(s), the effect of temperature and humidity can adversely affect both the size distribution of the delivered formulation (which can reduce the dosage at the target area of delivery) and the delivery of the drug from the device.

For nebulizers, pressurized metered-dose inhalers (pMDIs), and dry-powder inhalers (DPIs), measurement of particle / droplet size throughout a stability study is a key issue, as in addition to governing the target area of the delivery, it can also determine the rate of dissolution and bioavailability at the target site.

Normally, during early formulation development, accelerated feasibility studies will have been designed to ensure that any potential excipient compatibility issues have been identified quickly, however the effect of temperature and humidity on the performance of the formulation / device combination needs to be understood as early as possible.

Intertek has been working in the inhaled and nasal fields for over 25 years and has the necessary experience to help design, implement and support full development, stability and testing services that are designed to provide the right information at the right time.