Effect of Magnesium Stearate and Fines on Delivery of Dry Powder for Inhalation using Sucrose as a Carrier

Abstract

Typically, lactose is utilised as carrier in Dry Powder Inhaler commercially. However, with the widening scope of DPI in therapeutic categories other than COPD and asthma, a need for the alternate carrier is arising. In this study, we used sucrose, a non-reducing sugar, as an alternate carrier. Effect of addition of fines and magnesium stearate was studied on powder flow properties and aerosolization performance. The air jet milling technique was used to generate sucrose fines. DSC and XRD studies showed no change in sucrose polymorph upon micronization. Levosalbutamol sulphate was used as a model drug, powder blends were prepared by low shear tumbling type blender. Powder formulations were studied for PSD, blend homogeneity, and flow properties. The percentage of particles smaller than 5 microns rose when fines were added as indicated by PSD data. SEM study revealed that the added fines get adsorbs on the coarse carrier, thus minimizing the adhesive interactions between drug and coarse carrier. In-vitro deposition was studied using low and high resistance devices on glass Twin Stage Impinger (TSI). Addition of fines and the magnesium stearate improves aerosolization performance showing higher Fine Particle Fraction (FPF) by almost 2 folds than the formulation containing coarse carrier alone.