The infrared spectrum is one of the strongest proofs of a substance's identity and is used as the identity test for raw materials in pharmacopoeias. The sample spectrum is compared with that of the reference standard to evaluate whether the active substance or excipient is the declared substance. Analysis is performed on an FTIR (Fourier transform infrared) spectrometer using the ATR (attenuated total reflection) technique; solid, liquid, paste and film samples are usually measured without preparation. The spectrum is compared with reference libraries to identify the material.
This service is intended for research and development, supplier comparison and preliminary checks. Release and official quality control testing of licensed medicines must be carried out in authorised (GMP) laboratories as required by regulation.
Assessed
- Identity of active substances and excipients (cellulose derivatives, lactose, stearates etc.)
- Spectral comparison with a reference standard or approved batch
- Comparison of raw materials between suppliers
Reference Methods
- Ph. Eur. 2.2.24 – Absorption spectrophotometry, infrared
- USP <197> – Spectrophotometric identification tests
- USP <854> – Mid-infrared spectroscopy
Samples
A sample of the reference standard or approved batch to be compared must be sent with the sample.