Amorphous lactose solid dispersion co-spray-dried with magnesium stearate as a novel lactose carrier for dry powder inhalers

Abstract

Purpose

To overcome the strong inter-particulate interactions between the drug and carrier in dry powder inhalers (DPIs), an amorphous lactose solid dispersion (ALSD) was developed by co-spray drying lactose with magnesium stearate (MgSt) as a novel carrier for fluticasone propionate (FP).

Methods

To investigate the effects of carrier size, morphology, surface properties, and blending time on aerodynamic performance, the ALSD was compared with commercial references: rough-surfaced spherical lactose (SuperTab^® SD11), tomahawk-shaped lactose (Lactohale^® 200), and spherical spray-dried lactose, both with and without MgSt. A design of experiments (DoE) approach was employed to optimize the MgSt concentration and blending time.

Results

Based on the DoE results, the optimal MgSt amount was established at 0.2% (w/w), with a blending time design space ranging from 30 to 60 min. Remarkably, the optimized ALSD formulation achieved a fine particle fraction (FPF) of 59.62%. This performance substantially outperformed the reference carriers, exhibiting absolute increases of approximately 25.1 and 41.3% points compared with the FPFs of Lactohale^® 200 (34.53%) and SuperTab^® SD11 (18.30%) blended with 0.2% MgSt, respectively.

Conclusion

This study demonstrates that while carrier size is a contributing factor, morphology, surface properties, and blending time are critical determinants of aerosolization efficiency. Ultimately, the engineered ALSD successfully mitigates drug–carrier adhesion, markedly improving the aerodynamic performance of FP and representing a highly promising carrier for advanced DPI formulations.

Continue reading here

Kim, B., Kim, K., Yoon, Y.B. et al. Amorphous lactose solid dispersion co-spray-dried with magnesium stearate as a novel lactose carrier for dry powder inhalers. J. Pharm. Investig. (2026). https://doi.org/10.1007/s40005-026-00

Read also our introduction article on Magnesium Stearate here: