Introduction

Chronic respiratory conditions place a substantial burden on global health, with chronic obstructive pulmonary disease (COPD) alone affecting approximately 4 % of the global population and ranking as third leading cause of death worldwide (NCD Alliance, 2024). These conditions, such as cystic fibrosis, emphysema and chronic bronchitis, are characterized by the overproduction of thick, viscous mucus within the airways. Impaired clearance of mucus obstructs airflow, promotes recurrent infections, and significantly reduces patients' quality of life. Effective mucolytic therapy is therefore important to managing these conditions and preventing disease progression.

To address this, our assignment focuses on the development and formulation of an Acetylcysteine 20 % w/v Nebulizing Solution, designed for direct delivery to the respiratory tract via inhalation. Acetylcysteine is an N-acetyl derivative of the amino acid L-cysteine, and its free thiol (-SH) group is responsible for its mucolytic action. It cleaves disulfide bonds that cross link mucoprotein stands in the respiratory mucus, reducing its viscosity and making it easier for patients to expectorate (Pfizer, 2023). To ensure the drug remains chemically stable in solution, our formulation incorporates excipients for pH control, tonicity and oxidation.

Solutions are a well-suited dosage form for nebulizing solutions as they form a homogenous, single-phase system that can reliably be aerosolised into a fine mist without the risk of dose non-uniformity that is seen with suspensions and emulsions. Our formulation is designed for direct nebulization, prioritising chemical stability, patient safety, and ease of administration.