Identification and Structural Elucidation of New Process Impurity in Testosterone.

Area of Science:

• Pharmaceutical Chemistry
• Analytical Chemistry
• Organic Chemistry

Background:

• Testosterone is a crucial hormone with various pharmaceutical applications.
• Ensuring the purity of pharmaceutical compounds like testosterone is vital for patient safety and drug efficacy.
• Pharmacopeial methods are essential for controlling the quality of active pharmaceutical ingredients.

Purpose of the Study:

• To identify, isolate, and characterize a potential unknown impurity in testosterone.
• To ensure testosterone quality meets stringent European pharmacopeial standards.
• To elucidate the structure of a novel impurity exceeding 0.10%.

Main Methods:

• Analysis of testosterone using European pharmacopeial methods for related substances via high-performance liquid chromatography (HPLC).
• Isolation of the unknown impurity utilizing preparative HPLC with a Symmetry C18 column.
• Characterization of the isolated impurity through Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS), Proton Nuclear Magnetic Resonance (1H NMR), Carbon-13 Nuclear Magnetic Resonance (13C NMR), and Distortionless Enhancement by Polarization Transfer (DEPT) spectroscopy.

Main Results:

• One new unknown impurity was detected in testosterone alongside existing pharmacopeial impurities.
• The unknown impurity was successfully isolated using preparative HPLC.
• Spectroscopic analysis confirmed the impurity's structure as bisnoralcohol, adhering to International Council for Harmonisation (ICH) guidelines.

Conclusions:

• The study successfully identified and characterized a previously unknown impurity in testosterone as bisnoralcohol.
• The findings contribute to the quality control and safety assessment of testosterone drug products.
• This detailed characterization supports regulatory compliance and pharmaceutical manufacturing standards.