Formulation and Quality – Chemical
2019 PharmSci 360
Freezing point depression osmolality method is the most commonly used method in determination of osmolality. It is usually a very robust method for small molecule or low protein concentration products. However, as the protein concentration increases (e.g >100 mg/mL), freezing of samples can become an issue. Osmometers using less test volume may solve non-freezing problem, but accuracy and precision can be compromised. Thus, selection of a robust, accurate and precise osmolality measurement method is very critical especially during setting up specification and method transfer. This presentation includes examples of protein samples tested by several models (various test volume) and the results are compared to the predicted/theoretical values. Based on our findings, comparing the measured results with predicted theoretical values and/or vapor pressure depression osmolarity's results to confirm accuracy is strongly recommended.