Validated UPLC method for determination of unbound bile acids in colesevelam HCl tablets.

A simple, precise and accurate gradient reverse-phase ultra-performance liquid chromatographic method was developed for the quantitative determination of bile acids [glycocholic acid (GCA), glycochenodeoxycholic acid (GCDA) and taurodeoxycholic acid (TDCA)) in in vitro bile acid-binding study of Welchol tablets. The method was developed using Phenomenex Kinetex C18 (50 × 2.10 mm, 1.7 µm) column with mobile phase containing a gradient mixture of solvent A consisting of 0.02 M tetrabutylammonium phosphate (pH 7.5) and solvent B consists acetonitrile. The eluted compounds were monitored at 210 nm and the runtime was within 2 min. The binding parameter constants of Colesevelam HCl tablets 625 mg were determined using the Langmuir approximation at pH 6.8 by UPLC. The method is selective and capable of detecting bile acids in the presence of placebo matrix. The method has been validated with a lower limit of quantitation of 0.01 mM for bile acids. A linear response function was established for the range of concentrations 0.01-30.0 mM (r > 0.99) for GCA, GCDA and TDCA. The intra- and interday precision values for bile acids met the acceptance as per Food and Drug Administrations guidelines. The developed method was applied to in vitro bile acid-binding studies of Colesevelam HCl tablets.

Colesevelam and colestipol: novel medication resins in the gastrointestinal tract.

We report the morphologic description of the bile acid sequestrants (BAS) colesevelam and colestipol, as well as the largest series of cholestyramine. Histologically similar medication resins from 4 institutions were prospectively collected over 1 year (26 specimens, 15 patients). Comorbidities included hyperlipidemia (4/15), hypertension (4/15), inflammatory bowel disease (4/15), coronary artery disease (3/15), diarrhea (7/15), hypothyroidism (2/15), and ischemic bowel (1/15). Sites of involvement included the esophagus (1/26), stomach (1/26), small intestine (1/26), ileocecal valve (1/26), and colorectum (22/26). Associated histologic diagnoses included normal (8/26), chronic mucosal injury (11/26), acute inflammation (9/26), erosion/ulceration (6/26), and cytomegalovirus (2/26). The BAS resins were histologically indistinguishable from each other; they were all eosinophilic on hematoxylin and eosin (H&E) and lacked internal "fish-scales." To validate these observations, respective medications were submitted for histologic processing; the processed medications were identical to those in the patient specimens. Rare, irregular "fracture" lines presented diagnostic pitfalls by mimicking the true "fish-scales" of Kayexalate and sevelamer. Clues to the correct identification of BAS include recognition that the "fracture" lines were subtle, irregular, and restricted to large fragments or thick sections, likely representing a processing artifact. Moreover, Kayexalate is violet on H&E and black on acid fast bacillus, and sevelamer characteristically displays a 2-tone color on H&E and is magenta on acid fast bacillus. An association with inflammatory injury was seen (15/26). We believe that the BAS are innocent bystanders in complicated patients, although we cannot exclude their ability to cause mucosal injury in specific settings.

Development and validation of rapid ion-chromatographic method with conductivity detection for trace level determination of allylamine in sevelamer drug substances.

A sensitive and rapid ion chromatography (IC) method was developed for the low level determination of allylamine (AAM) in sevelamer (SVM) drug substances, i.e., sevelamer hydrochloride (SVH) and sevelamer carbonate (SVC). This method utilized a Dionex Ion Pack CS14 IC column, a mobile phase of 10mM methane sulfonic acid with conductivity detection. The total chromatographic run time was as short as 8 min. The various factors involved in the sample preparation such as, extraction solvent, extraction time and stirrer speed were evaluated. This method was validated as per United States Pharmacopoeia (USP) and International Conference on Harmonization (ICH) guidelines in terms of detection limit, quantitation limit, linearity, precision, accuracy, specificity and robustness. Linearity of the method was very good over the concentration range of 9-750 µg/mL with the coefficient of determination (r(2)) 0.999. The detection and quantitation limit of AAM were 2.7 and 9.0 µg/mL, respectively. The recovery data obtained for AAM were between 97% and 109%. Also, the specificity of the method was proved through IC coupled with mass spectrometer (IC-MS). The developed method was found to be robust and applied successfully to determine the content of AAM in Sevelamer bulk drugs.

Cases of fatal intoxication with Ketogan.

A survey of 76 cases of fatal intoxication with Ketogan which occurred in Eastern Denmark over the period 1985-1991 showed that the cause of death was Ketogan alone in 27 cases, in combination with alcohol in 23 cases, and in combination with other drugs in 26 cases. The average age, percentage of females, drug addicts and alcohol abusers and the manner of death were also recorded. There was a significant difference between the median values of the blood concentrations of ketobemidone where the blood alcohol concentration (BAC) was zero and where it was greater than 1 mg/g, and also between the median values of the blood concentrations from fatal intoxications and those from living persons.

[Safety of animal husbandry products produced by using allyl isothiocyanate-preserved feeds]. / Izuchenie bezvrednosti producktov zhivotnovodstva, poluchennykh pri ispol'zovanii kormov, konservirovannykh allilizotiotsianatom.

To examine the safety of foods (meat and milk) obtained from animals whose feeds were preserved with allyl isothiocyanate (AITC), the authors investigated the status and development of animals, some aspects of protein, lipid and carbohydrate metabolism, some enzymes, hemopoiesis and reproduction function of Wistar rats fed diets containing the above products (55 g dry milk or 50 g boiled meat per 100 g diet). To measure the residual quantity of allylamine (AA), the main metabolite of AITC, a chromato-fluorometric method with the use of dansyl chloride was devised, permitting the detection of 2 ng AA in the spot. The relative standard deviation was 0.14-17. The degree of AA extraction amounted to 96%. The method made it possible to detect the residual quantity of AA in the kidneys (up to 12.2 +/- 2.0 micrograms/kg) and in the liver (up to 83.1 +/- 12.4 micrograms/kg). The data obtained evidence that AA cannot be used as conservant for manufacturing feeds for agricultural animals.