The use of different sugars as fine and coarse carriers for aerosolised salbutamol sulphate

The aim of this study was to investigate the dispersion and deaggregation o f a model drug, salbutamol sulphate (SS), using lactose, mannitol or sorbit ol as coarse and fine carriers. Binary and tertiary formulations containing micronised salbutamol sulphate (SS) and sieved (63-90 mum) coarse sugar cr ystals or salbutamol sulphate (SS) with a mixture of coarse and fine sugar particles were prepared. Factorial design was employed to investigate the e ffects of three variables, i.e. the chemical entity of the coarse sugar car rier, the chemical entity of the fine sugar and the concentration of fine s ugar, on the dispersion and deaggregation of salbutamol sulphate after aero solisation at 60 l/min via a Rotahaler(R) into a twin stage liquid impinger (TSI), The binary formulations containing the different sugar entities pro duced differences in the fine (<6.4 <mu>m) particle fraction (FPF) of SS in a decreasing order of mannitol > sorbitol > lactose, but failed to produce efficient dispersion of SS since the FPF was < 10%. Adding fine sugar part icles and increasing their concentration to the binary mixtures generally r esulted in an increase in the FPF of salbutamol sulphate. The chemical natu re of the fine carriers was found to play a less important role in determin ing respirable fraction of the drug than the coarse carriers. In conclusion , other sugars such as mannitol or sorbitol, besides lactose, may be employ ed as coarse and/or fine carriers for incorporation into dry powder aerosol Formulations to increase FPF. (C) 2000 Published by Elsevier Science B.V.