Lysozyme-Based Microspherical Particles for Delivery of Nalidixic Acid: Preparation, Composition Optimization, and Solubility Study

Abstract The development of effective delivery systems for poorly soluble pharmaceuticals remains a critical challenge in modern pharmaceuticals. This study explores the use of lysozyme, a biopolymer with unique immunological and stabilizing properties, as a matrix for creating amorphous solid dispersions of nalidixic acid, a model hydrophobic antibiotic. By optimizing the composition using differential scanning calorimetry and X-ray powder diffractometry, a range of ratios of protein matrix and active pharmaceutical ingredient was determined in which amorphous solid dispersions are formed. Spray drying was used to produce microspherical particles suitable for inhalation therapy, resulting in particles predominantly 2–5 μm in size, suitable for alveolar deposition. This work demonstrates the potential of protein carriers such as lysozyme not only to enhance solubility and bioavailability but also to provide a synergistic therapeutic effect. The developed strategy for creating a dosage form is promising for improving the pulmonary delivery of other poorly water-soluble drugs while simultaneously reducing the required doses and minimizing side effects.