Active pharmaceutical ingredients (APIs)

In line with international pharmacopeias

Capsules and other pharmaceutical products must be monitored in view of their API content

For innumerous API monographs, Metrohm offers you pharmacopeia-compliant analytical instruments and a variety of applications including pH and conductivity measurement, titration, ion chromatography, voltammetry, and spectroscopy.

Titration alone covers more than 1000 API monographs of the United States Pharmacopeia (USP).

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Titration – a straightforward method with many application possibilities

Titrando for potentiometric titration with Dosino dosing systems

Because of their simplicity and accuracy, titration methods are used for a large proportion of the content determinations described in the monographs.

Metrohm has developed hundreds of titration methods with Metrosensors based on the U.S. Pharmacopeia (USP<541>) and European Pharmacopoeia.

These methods include aqueous and nonaqueous acid-base titrations as well as redox, surfactant, and photometric titrations.

> Different titration types for APIs

Chondroitin sulfate, bismuth nitrate, and zinc sulfate by photometric titration

Titrations using color indicators are widely used in pharmacopeias. When performed manually, the results depend, quite literally, on the eye of the beholder. Photometric titration using the Optrode makes it possible to replace this subjective determination of the equivalence point with an objective process that is completely independent of the human eye.

The great advantage of this is that the chemistry does not change – that is, the standard operation procedure generally does not have to be adapted.

There are numerous applications in the pharmacopeia that recommend photometric titration for the analysis of APIs.

Pharmacopeia-compliant examples cover the analysis of chondroitin sulfate for treating osteoarthrosis, of bismuth nitrate for treating gastric disorders, and of zinc sulfate as an immunomodulator, to name but a few.

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Photometric titrations with the Optrode

The Optrode offers eight wavelengths, ranging from 470 to 660 nm, and thus covers a broad spectrum of color indicators

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Multicomponent analysis of antibiotics 

Gentamicin antibiotic determination with ion chromatography

Ion chromatography: One method – Many APIs

Active pharmaceutical ingredients in tablets can be accurately determined by ion chromatography in accordance with the U.S. Pharmacopeia and European Pharmacopoeia. Prominent examples are the antibiotics gentamicin, neomycin, and cefadroxil, to name but a few.

> List of APIs that IC can analyze

Separation of structurally similar antibiotics

A famous API is gentamicin. It belongs to the World Health Organization’s List of Essential Medicines. Gentamicin is a bactericidal antibiotic. With its aminoglycoside group, it blocks protein biosynthesis by binding to ribosomes, thereby causing mistakes in the translation from mRNA to DNA.

IC determination of the antibiotic gentamicin with pulsed amperometric detection

Gentamicin consists of several closely related compounds, namely gentamicin C1, gentamicin C1a, and gentamicin C2, C2a, and C2b.
In spite of the structural similarity, IC achieves a good separation of the different gentamicin components.


API analysis with near-infrared spectroscopy

Calibration of CPM content with near-infrared spectroscopy and high-performance liquid chromatography

NIRS – Fast, nondestructive, and noninvasive

NIRS offers numerous advantages over many wet-chemical analytical methods. A diverse range of parameters can be determined simultaneously with just one fast, noninvasive, and nondestructive analysis. Multivariate chemometric calibration models allow to derive the API concentration from spectral data.

Calibration model for the quantitative determination of the API content of tablets by the example of chlorpheniramine maleate (CPM)

NIR analysis establishes a connection between the target value of a determination – in this case, CPM content – and the measured data in the spectrum.

Fast and simple endurance testing with NIRS

Sustained-release formulations which gradually release APIs have numerous therapeutic benefits, but they involve time-consuming quality control.

NIRS offers a fast and simple alternative to tedious dissolution testing: by using NIRS and appropriate calibration models, the release of APIs from sustained-release tablets can be predicted accurately within a matter of minutes.


Azathioprine, cefamandole, diclofenamide, and procarbazine by voltammetry

Semiautomated voltammetry system for voltammetric trace analysis

Electrochemically active pharmaceutical ingredients, such as azathioprine, cefamandole, diclofenamide, and procarbazine, can be determined directly with polarography in accordance with USP<801>.

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