Aim: EPAS (evaporative precipitation into aqueous solution) was used in the current
studies to prepare azithromycin nanosuspensions and investigate the physicochemical characteristics
for the nanosuspension batches with the aim of enhancing the dissolution rate of the nanopreparation
to improve bioavailability.
Methods: EPAS method used in this study for preparing azithromycin nanosuspension was
achieved through developing an in-house instrumentation method. Particle size distribution was
measured using Zetasizer Nano S without sample dilution. Dissolved azithromycin nanosuspensions
were also compared with raw azithromycin powder and commercially available products.
The total drug content of nanosuspension batches was measured using an Ultra-Performance
Liquid Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent
was measured using Gas Chromatography (GC).
Results: The average particle size of azithromycin nanosuspension was 447.2 nm and total drug
content was measured to be 97.81% upon recovery. Dissolution study data showed a significant increase
in the dissolution rate for nanosuspension batch when compared to raw azithromycin and
commercial version (microsuspension). The residual solvent found for azithromycin nanosuspension
is 0.000098023 mg/mL or 98.023 ppb.
Conclusion: EPAS was successfully used to prepare azithromycin nanoparticles that exhibited a
significantly enhanced dissolution rate. Further studies are required to scale up the process and determine
long term stability of the nanoparticles.