N-Nitrosamine Formation in Pharmaceutical Solid Drug Products: Experimental Observations

Area of Science:

• Pharmaceutical Sciences
• Drug Product Quality
• Chemical Analysis

Background:

• N-nitrosamines are a growing concern in medicinal products.
• Limited data exists on N-nitrosamine formation within pharmaceutical drug products.
• Regulatory bodies and pharmaceutical companies are actively investigating these impurities.

Purpose of the Study:

• To investigate N-nitrosamine formation in solid dosage forms.
• To determine if secondary and tertiary amines in drug products can nitrosate due to nitrite in excipients.
• To explore factors influencing N-nitrosamine generation in solid pharmaceutical formulations.

Main Methods:

• Formulation of solid dosage forms using model amines and common excipients with and without added nitrite.
• Testing of various amines with differing chemical structures, solubilities, and pKa values.
• Monitoring N-nitrosamine formation post-processing and under stressed stability conditions.

Main Results:

• N-nitrosamine formation was confirmed in solid drug product formulations.
• Formation rates depend on amine solubility, nitrite levels, local acidity, and processing methods (amorphous > wet granulation > direct compression > dry blends).
• Formation levels plateaued below theoretical maximums, and tertiary amines were less reactive than secondary amines.

Conclusions:

• N-nitrosamine formation is a tangible risk in solid drug products, influenced by formulation and processing.
• Risk assessment should consider amine properties, nitrite presence, and dosage form characteristics.
• Trace amine impurities pose a lower risk compared to higher concentrations of secondary amines.