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. Total drug content of nanosuspension batches were measured using an Ultra-Performance Liquid
Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent was measured using gas
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 significant increase in 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 significantly enhanced
dissolution rate. Further studies are required to scale up the process and determine long term stability of the nanoparticles.