Sirdupla™i pressurised metered dose inhalers (pMDIs) (test products) have been developed to match the Seretide® Evohaler®ii mid and high strength pMDIs (reference products) containing 25 mcg/actuation of Salmeterol (as Salmeterol Xinafoate) and either 125 or 250 mcg/actuation of Fluticasone Propionate.
Following the completion of feasibility studies, the aerodynamic particle size distribution (APSD) for Sirdupla™ were closely matched with the reference products, for both drug substances, with the exception of throat deposition as measured by Andersen Cascade Impactor (ACI).
Optimisation studies were therefore performed to investigate the potential to reduce the throat deposition observed for the test products. Initial optimisation was performed on the mid strength test product using laboratory scale equipment. The APSD data confirmed that a reduction in throat deposition was observed for the optimised mid strength test product. Although a slight shift in the APSD distribution was noted on plates 3 and 5, the APSD match with the reference product was considered suitable for continued product development.
Following these optimisation studies, Sirdupla™ pMDI was scaled up to development scale equipment for both the mid and high strength test products, prior to the manufacture of the clinical and primary stability batches.