Evaluation of Respirable Fraction by using Next Generation Impactor of Levosalbutamol Sulphate and Ipratropium...

A lung condition in which the passage of air into the lungs is obstructed, is treated using a combination pharmaceutical aerosol (Pressurised Metered dosage Inhaler) dosage form, such as Levosalbutamol Sulphate (LS) and Ipratropium Bromide (IB) pressurized inhalation, which contains 50 μg and 20 μg, respectively. Aerodynamic particle size distribution (APSD) aids in comprehending the likelihood of particle deposition in the lungs. In addition to being crucial for the efficacy and safety of medications, the respirable fraction is a significant critical quality attribute (CQA) for nasal and orally inhaled medicinal formulations.

The evaluation of in-vitro respirable fraction utilizing Next Generator Impactor (NGI) simulates drug particle deposition in the patient's lungs. The current study used a sensitive highpressure liquid chromatography technique to assess the deposited respirable fraction through APSD from NGI, as aerodynamic properties of the delivered dosage.

The samples are subjected to NGI and analyzed on an X-bridge C18 (50 x 4.6), 3.5 μm with 35°C column oven, volume of injection 100 μL, and 0.5 mL per min flow rate using a mobile phase that is a 75:25% v/v combination of Heptane sulphonic acid sodium salt buffer and Acetonitrile in high-pressure liquid chromatography. The designed approach was validated for its anticipated function and determined the respirable fraction of the delivered dose.

The respirable fraction (fine particle dose) in μg for Levosalbutamol sulfate and Ipratropium bromide were observed 27.644 ± 1.9 and 11.045 ± 1.8, respectively. The fine particle fraction in percentage for Levosalbutamol sulfate and Ipratropium bromide were observed 55 ± 1.8 and 56 ± 1.8, respectively. There is no method reported for the determination of Levosalbutamol sulphate and Ipratropium bromide from respirable fraction.

The reliable results generated by novel combined in-vitro evaluation of LS and IB respirable fractions - correspond to lung deposition in a clinical study, which is about ≤ 5μm particle size in given doses of LS and IB inhalers.