Acid value as a central, objective quality factor for lipid excipients

The selection and qualification of a manufacturer of excipients and active ingredients is one of the main tasks of quality management, which aims, among other things, to ensure the manufacture of effective and safe pharmaceuticals. In this context, monographs serve as a guide to evaluate raw materials regarding their physico-chemical properties and also help to compare different sources of the “supposedly” same raw material.

The parameter “acidvalue” is a requirement for lipid excipients in almost all materials. So why should special attention be paid to this seemingly trivial chemical parameter and the procedural competence of a manufacturer to reproduce low values?

In a narrower sense, this parameter quantifies the content of free (fatty) acid in the raw material, which is typically regarded as an undesirable impurity. Minimum levels are usually not specified, but the European Pharmacopoeia defines values of e.g. 0.2 – 6 mg KOH per gram of substance as upper parameter limits.

First of all, this acid value provides information about how much effort was invested during production to purify the excipient or active substance. However, certain contents are always permissible if the monograph limits are observed. A certain increase in this valuecan occur spontaneously over the course of the shelf life. It should be considered that free fatty acids are the result of natural processes in the material and can have catalytic effects. Elevated levels in fresh and stored material can be problematic, since free fatty acids tend to cause or catalyze a number of undesirable reactions with themselves, the other excepients and the active ingredients. The consequences may be a limited shelf life and effectiveness of the final drug product.

We, IOI Oleo GmbH, understand the low acid value of our products as one of the primary indicators of quality and stability for well-made lipids and as a contribution to stable and long-lasting pharmaceuticals. Our team will be happy to answer any further questions you may have regarding the objective assessment of the quality of lipid excipients and active ingredients.