pH-stat in theory and practice in pharmaceutical and biomedical industries

The study of the kinetics of a chemical reaction over time is one of the simplest and quickest ways of measuring the efficiency of active ingredients in drugs for the pharmaceutical industry.

The most common examples are the measurement of enzyme kinetics and the activity of antacid products. However, there are many other examples of chemical reactions versus time in organic and mineral chemistry such as the measurement of the dissolution rate of fertilisers or the solubility of an additive to cattle feed to test its digestibility.

The vast majority of reaction kinetics concern chemical reactions that free or consume H3O+ or OH- ions. Obviously, their speed of formation depends on operating conditions, in particular the pH of the reactive media. To study this, it is therefore important to keep the pH of the reactive media stationary. This is what is known as pH-Stat.

A pH-Stat study takes place as follows:

- Determining an optimum value for the pH of the studied reaction,

- Keeping the pH constant by adding a reagent to neutralise OH- or H3O+ ions.

- Calculating the kinetics of the studied reaction based on the consumption of reagent required to keep the pH constant over time.

As pH-Stat is frequently used for analytical control especially in the pharmaceutical and biomedical industries, Radiometer Analytical has decided to share its technical expertise in the subject by producing a free theory and practice guide.

Enter 28 or XX at www.scientistlive.com/elab

- Radiometer Analytical SAS is based in Villeurbanne, France. www.radiometer-analytical.com/free

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