The aim of this study was to prepare lipid microparticles
(LMs) loaded with the polar bronchodilator agent salbutamol, and
designed for sustained release pulmonary delivery. The microparticles
were produced by melt emulsification followed by a sonication step,
using different biocompatible lipid carriers (tristearin, stearic acid
and glyceryl behenate) and phosphatidylcholine as the surfactant. The
use of salbutamol free base, rather than salbutamol sulphate, was
necessary to obtain the incorporation of the drug in the lipid particle
matrix. The prolonged release of salbutamol base was achieved only by
the glyceryl behenate microparticles (40.9% of encapsulated drug being
released after 8 h). The salbutamol loading was 4.2% ± 0.1 and the mass
median diameter, determined by laser diffraction, ranged from 4.8 to
5.4 µm. The sustained release of LMs were formulated as a carrier-free
dry powder for inhalation and exhibited a fine particle fraction of
17.3% ± 2.2, as measured by multi-stage liquid impinger.
