The application of the Attenuated Total Reflectance spectroscopy (ATR-FTIR) in compatibility studies of gabapentin with selected excipients

Abstract

The compatibility of the active pharmaceutical ingredient with excipients is required at the drug product development stage. Chemical interactions between the active pharmaceutical ingredient and other components of a dosage form may influence the solubility, bioavailability and pharmacological activity of an active pharmaceutical ingredient and consequently, the efficacy and safety of pharmacotherapy may be changed significantly. In spite of the fact that compatibility testing is recommended by ICH (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use), there is still a lack of definite and clear guidelines which specify the methodology and conditions of compatibility studies. The aim of this research study was to evaluate the usefulness of Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy technique (ATR-FTIR) in monitoring changes in gabapentin structure as a result of chemical interactions with selected excipients. The samples of binary mixtures containing equal masses of gabapentin and selected excipients were analyzed. Infrared spectra were recorded in the range of wavenumbers from 4000 cm-1 to 600 cm-1 immediately after the samples preparation and after 5 days of their exposure to the elevated temperature of 50°C. The analysis of registered ATR-FTIR spectra indicated some shifts in absorption bands, modifications of their shape or intensity, and the disappearance or appearance of additional peaks. These changes in infrared spectra confirmed the occurrence of chemical interactions between gabapentin and selected excipients. The usefulness of ATR-FTIR spectroscopy as a rapid screening technique for preliminary analysis of chemical interactions of gabapentin has been shown. For a thorough evaluation of the chemical interactions, further studies are recommended by means of complementary techniques such as Raman spectroscopy, differential scanning calorimetry or high-performance liquid chromatography.

Keywords

• gabapentin
• compatibility studies
• atr-ftir
• preformulation studies