Development and characterization of meropenem dry powder inhaler formulation for pulmonary drug delivery.

Meropenem (MPN), a broad spectrum β-lactam antibiotic, has been increasingly used in the treatment of moderate to severe bacterial infections. However, due to its short plasma half-life and chemical instability in solution form, it has been challenging to use in the intravenous formulation. This study aims to develop and characterize MPN dry powder inhaler (DPI) formulation for pulmonary delivery. The inhalable MPN particles (1-5 µm) were prepared by micronization. Lactose, L-leucine and magnesium stearate (MgSt) were used in the powder formulation as carriers and dispersibility enhancers. The formulations were characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman confocal microscopy, X-Ray powder diffraction analysis (PXRD), and differential scanning calorimetry (DSC) methods. The concentration of MPN was determined by using a validated HPLC method. The Fine Particle Fraction (FPF) of meropenem from powder mixtures was determined by a Twin Stage Impinger (TSI) at a flow rate of 60 L/min. The FPF of the original MPN was 1.91% which was significantly increased to 37.5% for the formulations with excipients. No physical interactions between the drug and the excipients observed. This study revealed the potential of a stable meropenem DPI formulation for pulmonary delivery.