Child Alberta Idealised Throat shown to deliver better IVIVRs

New experimental studies using the Child Alberta Idealised Throat (C-AIT) from Copley Scientific confirm that it provides data more representative of in vivo throat deposition than the standard USP/Ph. Eur. induction port used for routine inhaler testing. The results echo those observed with the Adult AIT (A-AIT) and indicate that both accessories have an important role to play in generating measurements that can be used to improve and/or target drug delivery by ensuring better in vitro in vivo relationships (IVIVRs). Better representation of deposition in the throat is recognised as a major concern in inhaled product testing, as evidenced by recent of FDA funding to support the experimental assessment of different mouth-throat models.

A stronger relationship between in vitro measurements and in vivo behaviour enhances the value of test data in an R&D setting, most especially when applying a quality by design approach. The standard USP/Ph.Eur. induction port is specified in the pharmacopoeias for cascade impaction testing to measure the aerodynamic particle size distribution (APSD) of the active ingredient in all inhaled drug formulations. However, it is known to under estimate the amount of drug that deposits in the throat.

Improving the realism and relevance of mouth-throat models for inhaled product testing’ details back-to-back studies with both the C-AIT and A-AIT, and the USP/Ph.Eur. induction port. Tests were carried out with two commercially available inhalers — one metered dose, the other dry powder. In all instances, the AIT accessories captured more of the emitted dose than the USP/Ph.Eur. induction port, most especially capturing a greater proportion of larger particles. These accessories therefore provide a more realistic measurement of both delivered dose and the particle size of that dose, a parameter that influences deposition behaviour in the lung.

The A-AIT and C-AIT are precision manufactured to extremely close tolerances and designed to interface with a wide range of cascade impactors.  Manufactured in metal, they have a highly reproducible, human-like geometry which delivers performance that is validated against clinical data across a broad range of flow rates. The C-AIT, which was introduced following successful trials with the A-AIT, is specifically for testing products for paediatric use and has a geometry based on measurements of the upper airway from nine children aged six to 14 years.