HPLC/UV/MS method application for the separation of obeticholic acid and its related compounds in development process and quality control

What is the role of current mass spectrometry in pharmaceutical analysis?

The role of mass spectrometry (MS) has become more important in most application domains in recent years. Pharmaceutical analysis is specific due to its stringent regulation procedures, the need for good laboratory/manufacturing practices, and a large number of routine quality control analyses to be carried out. The role of MS is, therefore, very different throughout the whole drug development cycle. While it dominates within the drug discovery and development phase, in routine quality control, the role of MS is minor and indispensable only for selected applications. Moreover, its role is very different in the case of analysis of small molecule pharmaceuticals and biopharmaceuticals. Our review explains the role of current MS in the analysis of both small-molecule chemical drugs and biopharmaceuticals. Important features of MS-based technologies being implemented, method requirements, and related challenges are discussed. The differences in analytical procedures for small molecule pharmaceuticals and biopharmaceuticals are pointed out. While a single method or a small set of methods is usually sufficient for quality control in the case of small molecule pharmaceuticals and MS is often not indispensable, a large panel of methods including extensive use of MS must be used for quality control of biopharmaceuticals. Finally, expected development and future trends are outlined.

Obeticholic acid-loaded exosomes attenuate liver fibrosis through dual targeting of the FXR signaling pathway and ECM remodeling

End-stage of liver fibrosis as a precancerous state could lead to cirrhosis and hepatocellular carcinoma which liver transplantation is the only effective treatment. Previous studies have indicated that farnesoid X receptor (FXR) agonists, such as obeticholic acid (OCA) protect against hepatic injuries. However, free OCA administration results in side effects in clinical trials that could be alleviated by applying bio carriers such as MSC-derived exosomes (Exo) with the potential to mimic the biological regenerative effect of their parent cells, as proposed in this study. Loading OCA into the Exo was conducted via water bath sonication. Ex vivo bio distribution studies validated the Exo-loaded OCA more permanently accumulated in the liver. Using CCL4-induced liver fibrosis, we proposed whether Exo isolated from human Warton's Jelly mesenchymal stem cells loaded with a minimal dosage of OCA can facilitate liver recovery. Notably, Exo-loaded OCA exerted additive anti-fibrotic efficacy on histopathological features in CCL4-induced fibrotic mice. Compared to baseline, Exo-mediated delivery OCA results in marked improvements in the fibrotic-related indicators as well as serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations. Accordingly, the synergistic impact of Exo-loaded OCA as a promising approach is associated with the inactivation of hepatic stellate cells (HSCs), extracellular matrix (ECM) remodeling, and Fxr-Cyp7a1 cascade on CCL4-induced liver fibrosis mice. In conclusion, our data confirmed the additive protective effects of Exo-loaded OCA in fibrotic mice, which suggests a valuable therapeutic strategy to combat liver fibrosis. Furthermore, the use of Exo for accurate drug delivery to the liver tissue can be inspiring.

A Sensitive HPLC-MS/MS Method for Determination of Obeticholic Acid in Human Plasma: Application to a Pharmacokinetic Study in Healthy Volunteers

A rapid and sensitive LC-MS/MS method was developed and fully validated for the determination of obeticholic acid in human plasma. Glimepiride was used as internal standard. For this method, liquid-liquid extraction was performed to extract analyte from the plasma samples. Chromatographic separation was performed on a C18 (2.1 × 50 mm, 2.7 μm, Agilent) column with isocratic elution using water containing 0.1% formic acid and acetonitrile containing 0.1% formic acid at a flow rate of 0.4 mL/min. The mass detection was performed in negative mode. The precursor-product ion pairs for MRM were m/z 465.3 → 419.3 for obeticholic acid and m/z 489.3 → 224.8 for the IS. The method exhibited great linearity over the concentration range of 0.150-100 ng/mL for obeticholic acid. The sensitivity, linearity, accuracy, precision, recovery, matrix effect and stability of this method were all within the acceptable limits. The method was successfully validated and applied to the pharmacokinetic studies in healthy Chinese volunteers after a single oral dose administration of obeticholic acid tablets of 10 mg, and the pharmacokinetic characteristics of obeticholic acid in human were reported for the first time.

Synthesis and characterization of new impurities in obeticholic acid

Novel and efficient synthetic strategies are developed for the first synthesis of two new impurities found in obeticholic acid. The synthetic routes to the impurities are designed without column purification using 4-nitrobenzoyl chloride as a selective protecting group. The impurities, which are obtained in good yields and high purity, are identified and characterized using high-resolution mass spectrometry, Fourier transform infrared, one-dimensional nuclear magnetic resonance (1H, 13C, distortionless enhancement by polarization transfer), and two-dimensional nuclear magnetic resonance (Correlated Spectroscopy, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, and rotating-frame Overhauser effect spectroscopy) techniques.