RSSL extends GMP services with amino acid analyser

Fully verified for the testing of 14 amino acids, the amino acid analyser has extended RSSL's range of GMP services.


RSSL has recently acquired an amino acid analyser (AAA) capable of performing ninhydrin positive substance (NPS) testing as well as ammonium limit testing, further extending RSSL’s range of GMP services to the pharmaceutical sector.

As per their European Pharmacopoeia (EP) monographs, the AAA has been fully verified for the testing of 14 amino acids. These are: Threonine, Serine, Valine, Proline, Leucine, Isoleucine, Histidine, Arginine, Lysine, Glycine, Alanine, Tyrosine, Cysteine, Phenylalanine.

If required, additional verification work to meet a client’s specific requirement can also be performed at RSSL.

Impurities have the potential to compromise the safety and efficacy of any medicine formulated with amino acids. In the past, these impurities have been quantified by Thin Layer Chromatography (TLC), which involves the separation of impurities on a plate. These impurities are then sprayed with ninhydrin and identified through comparison against reference solutions. The disadvantage of this technique is that the quantification of the impurities is purely visual and is therefore subjective and lacking in accuracy.

The EP has therefore begun the transition of moving the monograph testing for ninhydrin positive substances to a more accurate and reliable technique using an Ion Chromatography (IC) instrument. This instrument is coupled with a post-column derivatisation unit (Pickering Pinnacle PCX) which introduces the ninhydrin to the sample for quantification.

The test is sensitive to impurities at a reporting threshold of 0.05% and can determine whether the overall impurity level exceeds the limits defined in the monographs. As part of this analysis, the instrument can also perform the ammonium limit test as per the individual monographs.

Having this capability at RSSL further extends the range of GMP services services that we can offer to the pharmaceutical and bio-pharmaceutical sectors.