Advanced Particle Size Characterization of Famotidine Oral Suspension Using Laser Diffraction Technology

Abstract

Famotidine Oral Suspension USP, 40 mg/5 mL, is a widely used liquid dosage form for the treatment of acid-related gastrointestinal disorders, particularly in pediatric and geriatric patients who experience difficulty swallowing solid dosage forms. Particle size distribution (PSD) is a critical quality attribute of suspension formulations because it significantly influences physical stability, sedimentation behavior, dispersibility, dissolution characteristics, content uniformity, and overall product performance. The present study aimed to develop and validate a reliable particle size distribution method for Famotidine Oral Suspension USP, 40 mg/5 mL, using a Malvern Mastersizer 3000 laser diffraction analyzer. Method optimization was performed by evaluating critical analytical parameters, including dispersant selection, obscuration level, agitation rate, refractive index, and measurement conditions. Water was selected as the dispersing medium, and optimized analytical conditions were established to achieve consistent particle dispersion and reproducible results. The developed method was evaluated for precision, intermediate precision, and robustness. Method precision was assessed using six independently prepared samples and demonstrated excellent reproducibility, with %RSD values of 2.41%, 1.04%, and 1.00% for d(0.1), d(0.5), and d(0.9), respectively. Intermediate precision studies performed by a second analyst on a different day showed %RSD value within acceptable limits, confirming method reproducibility. Robustness testing involving deliberate variations in agitation rate and obscuration level also produced satisfactory results, indicating that the method remained unaffected by minor changes in analytical conditions. The results demonstrated that the developed laser diffraction method is precise, reproducible, and robust for the determination of particle size distribution in Famotidine Oral Suspension USP, 40 mg/5 mL, and is suitable for routine quality control and product characterization applications.