Chromatographic-based Identification of Degradation Products

Excipients often interact chemically with active pharmaceutical ingredients (APIs) in a negative way to produce new products, leading to degradation of the APIs. Especially when excipients and APIs are both highly mobile, there are more opportunities for chemical reactions occur between the two components. Therefore, consideration for chemical degradation becomes more critical and necessary. Nowadays, in order to select or design the appropriate excipient for each formulation, the accurate prediction and identification of degradation products is a key analytical activity in the drug development process. Assessing the stability and safety of drugs is an important part of ensuring drug efficacy and accelerating the development of innovative drugs. BOC Sciences has introduced a series of chromatographic techniques to isolate drug-excipient interaction impurity associated with the degradation process of APIs. Comprehensive characterization of degradation products can help us study the chemical reactions between drugs and excipients, which is critical for designing less reactive and more stable drug products.

Figure 1. LC-MS/MS Analysis of drug-excipient interactions. (Veeravalli, V.; et al. 2020)

Application

• Assess the toxicological impact of degradation products on the body
• Further confirm the mechanism of formation
• Improve the synthesis and manufacturing process of drug products
• Optimize the drug formulations

Our Standard Analysis Workflow

At BOC Sciences, our experts fully understand the regulatory requirements for impurity identification, and have rich project experience in the identification of the chemical impurities. Chromatographic techniques are very effective tools for the determination of chemical species present in pharmaceutical formulations, and chromatographic peak purity data can be used to identify pharmaceutical degradation impurities.

Figure 2. Schematic representation of oxidation reactions between the drug and excipient. (Gabrič, A.; et al. 2022)

Sample Preparation

• API and excipients alone; binary mixtures and ternary mixtures formed by API and each selected pharmaceutical excipient in different proportions
• The mixtures are prepared using an analytical balance and submitted to physically homogenized using a vortex for 5 minutes
• Divide each mixture into several portions. The first portion of the sample is analyzed immediately. The other portion of the samples are stored in a stability chamber for 3 and 6 months for testing

Separation Process

At BOC Sciences, we mainly employ HPLC method to separate the impurities with the application of a C18 column with good performance. The concentration of the drug substance is calculated by comparing the chromatograms of the drug substance, excipient, binary mixture, and ternary mixture. If the concentration of the drug in the mixture decreases, it means that a chemical reaction has occurred between the drug and the excipient, which leads to the degradation of the drug and therefore demonstrates the presence of chemical incompatibility.

Identification & Analysis

To further demonstrate the presence of chemical interactions, we use novel LC-MS and NMR techniques to identify and fully characterize the degradation products. We provide mass spectra of degraded impurities. Additionally, detailed characterization of impurities is accomplished by tracking changes and reporting the disappearance or generation of vibrational peaks in the spectra of reaction mixtures based on IR, FTIR, HRMS, ¹H/¹³C NMR and 2D NMR spectroscopy.