Best@BUCHI: Determining the Active Ingredient Content in Tablets by NIR-Spectroscopy

Authors: Nadja Doll (Dipl.Ing.(FH)), Lydia Lehwald (Dipl.Ing.(FH)), Company: Salutas Pharma GmbH, D-Barleben

Active Ingredient Content in Tablets with NIR SpectroscopyIntroduction:

In order to create a precise and robust calibration model for determining the active ingredient content of tablets, it is essential to choose a suitable calibration range. This range should cover at least 75 -125% of the nominal content of the active ingredient in 5% steps, in order to achieve sufficient accuracy of the calibration model. In the following the creation of two calibration models is described. These calibration models were created using two different types of tablets. Review the full study here

Captopril 25 mg tablets are clover-leaf shaped tablets and have an active ingredient content of 25 mg and a total weight of 160 mg. Ramipril 2.5 mg tablets are oblong (4mm x 8mm), are engraved on one side, contain 2.5 mg active ingredient and have a total weight of 80 mg.


Validation is described as the process of verifying a method. For this purpose, the method is investigated to determine whether it provides reproducible and reliable results under the conditions described. By dividing the spectra of the calibration set and the validation set, the software independently carries out an internal validation. Various guidelines require that a method is validated with the aid of a calibration, a validation and a test-set. This requirement was fulfilled by determining the active ingredient content of additional tablets by NIR-spectroscopy.


It is to be expected that, in the near future, the use of NIR spectroscopy for quantitative purposes will continually increase. NIR-spectroscopy is recommended as it offers the great advantage of directly analysing the active ingredient content.The advantages of NIR-spectroscopy – rapid, non-destructive analysis – are impressive. This analysis method offers the possibility of increasing process understanding of bulk pharmaceutical production when used directly at the tablet press (on-line) or alternatively as a process-near (at-line) application, thus improving product quality and productivity. Ultimately, this leads to lower production and quality costs.