Preparation of conjugated bilirubin from native bile and characteristic study

Abstract

Background: The quantification of serum bilirubin fractions is widely performed with both the diazo colorimetric and enzymatic methods. However, the degree of precision of these methods must be evaluated via bilirubin control serum, which can be prepared by adding bilirubin standard to based serum in order to raise the bilirubin fraction to an abnormal value. Unconjugated biilirubin (UCB) can be obtained commercially, but conjugated bilirubin (glucuronide form)(Bc) is unstable, and thus there are at present no such products on the market.

Objective: To isolate and characterize Bc using bovine bile as the raw material.

Method: Bc was prepared by isolation from fresh bovine gall bladder bile.The isolation method was modified after Lucassen (doctoral thesis, Univer. Utrech, 1961). Bc isolated from five preparations yielded approximately 50% of the original concentration in raw material. The Bc product exhibited a dark brownish yellow color, water solubility, hygroscopicity, a visible spectrum with peak maximum at 445 nm., diazo reactivity, and instability to air and light.

Discussion: This product was prepared in order to observe any characteristics that may be useful in possible further quality control work. Bc yield was unsatisfactory, which may be the result of instability during isolation and lyophilization. Bull Chiang Mai Assoc Med Sci 2008; 41: 62-71.