The Extraction And Purification Of Chenodeoxycholic Acid From Pig Bile Paste

Chenodeoxycholic acid (CDCA) exists in the bile of human, chicken, duck, pig and so on. CDCA is commonly used in clinical for the treatment of liver and gallbladder diseases.Ursodeoxycholic acid (UDCA) is the most used drug in the clinical for the treatment of cholesterol gallstone disease, while CDCA is the raw material for the synthesis of UDCA.Although chenodeoxycholic acid is rich in chicken or duck bile, and source of pig bile is avialible enough, but due to technical limitations, the chenodeoxycholic acid used in clinical is mainly extracted from chicken bile. As the increasing market demand of chenodeoxycholic acid, the producers seize the raw material market, leading to the rising price of chicken bile. In order to reduce cost, many producers hope that through technology innovation to realize the production of chenodeoxycholic acid from duck or pig bile. In addition,the bile resources of chicken, duck or pig slaughtering enterprises are always transformed to bile paste by middlemen for sale. According to this situation, this paper studied the extracting technology of chenodeoxycholic acid from pig bile paste so as to realize industrial production.In order to obtain the effective method of extracting chenodeoxycholic acid from pig bile paste, the work of this study was carried out from three aspects: ① the method and process conditions of extracing chenodeoxycholic acid from pig bile paste; ② the refining method of crude chenodeoxycholic acid; ③ the effect of solvents on the crystal morphology of chenodeoxycholic acid. The detailed work and results were as follows:(1) The four factors of methanol dosage, reaction temperature, calcium chloride dosage and pH of solution were studied. The optimum extracting conditions were obtained through the single factor and orthogonal experimental design, just as follows: methanol dosage (V) 10 times of bile paste (m), the reaction temperature was 55℃, the amount of 20% calcium chloride aqueous solution (V) was 3.5 times of bile paste (m), the solution pH was 13. The extraction yield was 82.23% under the optimum extracting conditions.(2) Chenodeoxycholic acid was purified by recrystallization, the effect of single or mixed solvents was studied. The results showed: when the recrystallization solvents were ethyl acetate chenodeoxycholic acid crystal had a lighter color. The effect of liquid-solid ratio, reflux time,concentrate liquid-solid ratio and crystallization temperature four aspects on recrystallization were studied, the single factor and orthogonal experiment were carried out. The optimal purification process parameters were as follows: 12 times ethyl acetate,reflux time was 2 h, concentrate liquid-solid ratio was 3 times,the temperature for crystallization was 0℃ . The product melting point was 168.2℃-168.6℃ , the rotation 11.75’. The purity of chenodeoxycholic acid was 98.61%.The effect of solvent on the crystal morphology of chenodeoxycholic acid was studied.Results showed: hexagonal solid prism chenodeoxycholic acid crystal with hole on the surface was obtained in ethyl acetate; granular crystal was obtained in acetonitrile; flaky crystal was obtained in ethyl acetate-acetonitrile mixed solvent; hexagonal canal-type structure with channels crystal was obtained in ethyl acetate-chloroform mixed solvent;hexagonal solid prism with smooth surface crystal was obtained in ethyl acetate-n-hexane mixed solvent. Chenodeoxycholic acid crystals of different solvents obtained have difference on IR spectra, DSC curves and X-ray image.