The optimized use of gas chromatography-mass spectrometry and high performance liquid chromatography to analyse the serum bile acids of patients with metabolic cholestasis and peroxisomal disorders

Optimization of RP-HPLC method with UV detection for determination of ursodeoxycholic acid in pharmaceutical formulations

Due to the low absorptivity of bile acids, the aim of this study was to develop and validate a simple and sensitive HPLC/UV method for quantification of ursodeoxycholic acid (UDCA) in pharmaceutical formulations. Effective separation was achieved on C18 end–capped column, with gradient elution of a mobile phase composed of 0.001 M phosphate buffer (pH 2.8±0.5) – acetonitrile mix, at flow rate 1.5 mL min-1, UV detection at 200 nm and injection volumes were 50 µL. The proposed HPLC method was fully validated according to the ICH guidelines and it was found to be simple, accurate, precise and robust. Key words: ursodeoxycholic acid, HPLC/UV, pharmaceutical formulations, validation

Laboratory diagnosis of disorders of peroxisomal biogenesis and function: a technical standard of the American College of Medical Genetics and Genomics (ACMG)

Peroxisomal disorders are a clinically and genetically heterogeneous group of diseases caused by defects in peroxisomal biogenesis or function, usually impairing several metabolic pathways. Peroxisomal disorders are rare; however, the incidence may be underestimated due to the broad spectrum of clinical presentations. The inclusion of X-linked adrenoleukodystrophy to the Recommended Uniform Screening Panel for newborn screening programs in the United States may increase detection of this and other peroxisomal disorders. The current diagnostic approach relies heavily on biochemical genetic tests measuring peroxisomal metabolites, including very long-chain and branched-chain fatty acids in plasma and plasmalogens in red blood cells. Molecular testing can confirm biochemical findings and identify the specific genetic defect, usually utilizing a multiple-gene panel or exome/genome approach. When next-generation sequencing is used as a first-tier test, evaluation of peroxisome metabolism is often necessary to assess the significance of unknown variants and establish the extent of peroxisome dysfunction. This document provides a resource for laboratories developing and implementing clinical biochemical genetic testing for peroxisomal disorders, emphasizing technical considerations for sample collection, test performance, and result interpretation. Additionally, considerations on confirmatory molecular testing are discussed.