Detection and Evaluation of process related impurities in Obeticholic Acid Drug material using HPLC Method

Obeticholic acid (OBE) is being used to treat primary biliary cirrhosis and cholangitis. An HPLC with refractive index detection method for eight process related substances of OBE was developed and verified for use in quality assurance laboratories for regular analysis. The separation and analysis were performed on YMC Triart C18 (3.0 µm particle size, 250 mm × 4.6 mm) column. Mobile phase employed consisted of 0.01N potassium phosphate buffer (3.0 ± 0.05 pH, set with 0.1% orthophosphoric acid) and acetonitrile at 45:55 (v/v) ratio. The method established for determination of eight impurities in OBE was validated and verified in keeping with International Council for Harmonisation guidelines. This method can be used for routine analysis of eight impurities in OBE bulk samples.

Tunable Nanosensor With a Horizontal Number Eight-Shape Cavity in a MIM Waveguide System

Optical devices play an important role in different fields, such as refractive index detection in food processing and the biochemical industry. In our work, a novel nanoscale optical structure, composed of a metal-insulator-metal waveguide with a stub and a horizontal number eight-shape cavity (HNEC), is presented. The transmission properties of this structure are investigated in detail by using finite element method The effects of geometric parameters on sensing performance are studied in detail. Moreover, the influences of an asymmetric resonator caused by shifting central rectangular cavity of HNEC on transmission spectrum are discussed. The changing parameters of HNEC resonator have different effects on different resonance dips. Then, when the parameters of this presented structure are fixed as a of 540 nm, b of 340 nm, S of 0, l of 70 nm and g of 10 nm, this intriguing structure can serve as a refractive index sensor, whose maximum sensitivity can reach 1,500 nm/refractive index unit with a figure of merit of 75. Therefore, this structure will contribute to the development of miniaturization of optical devices.