Helgi Jung Cook

In Vitro Effects of Albendazole Sulfoxide and Praziquantel against Taenia solium and Taenia crassiceps Cysts

ABSTRACT We investigated the minimum exposure times of prazicuantel (PZQ) and albendazole sulfoxide (ABZSO) required for their activities against Taenia cysts in vitro as well as the 50 and 99% effective concentrations. The results showed that although the effects of both drugs are time and concentration dependent, ABZSO acts much slower and is less potent than PZQ.

Sensitive high-performance liquid chromatographic assay for praziquantel in plasma, urine and liver homogenates

A high-performance liquid chromatographic method for the determination of praziquantel in plasma, urine and rat liver homogenates has been developed. It requires 2 ml of biological fluid, an extraction using Sep-Pak cartridges, a 0.05 M phosphate buffer solution (pH 5.0) for equilibrating and washing and ethyl acetate-diisopropyl ether for drug elution. The analysis was performed on an Ultrasphere ODS C18 column with a mobile phase of acetonitrile-water with ultraviolet detection at 217 nm. The results showed that the assay is sensitive (31.2 ng/ml), linear between 0.125 and 4.0 micrograms/ml, precise (coefficient of variation = 10%) and selective with other drugs currently administered with praziquantel.

The influence of polymorphism on the manufacturability and in vitro dissolution of sulindac-containing hard gelatin capsules

Abstract Context: Drug polymorphism could affect drug product dissolution, manufacturability, stability and bioavailability/bioequivalence. The impact of polymorphism on the manufacturability and in vitro dissolution profiles of sulindac capsules has not been studied yet. Objective: To evaluate the impact of polymorphism on the manufacturability and in vitro dissolution of sulindac hard gelatin capsules. Materials and methods: Sulindac crystal forms I and II (SLDI and SLDII, respectively) were prepared and characterized. Powder formulations containing one of the polymorphs, lactose and magnesium stearate (at three different levels) were prepared and their flow properties determined. Hard gelatin capsules were filled with the formulations and tested for fill-weight variations. Drug dissolution for SLDI- and SLDII-containing hard gelatin capsules was determined. Results: Differences in flow properties for each polymorph were observed, as well as for their formulations, which in turn affected capsule weight homogeneity. Statistically significant differences in the rate and extent of drug release were observed between SLDI- and SLDII-containing capsules. Discussion: Formulations containing SLDI showed a better manufacturability and a better dissolution profile than those with SLDII. Conclusion: Sulindac crystalline form I was the best candidate for hard gelatin capsule formulation because of its technological and in vitro dissolution properties.

Comparison of a high‐performance liquid chromatography method for quantification of carbamazepine with chemiluminescent microparticle immunoassay

Carbamazepine is an antiepileptic drug widely used for the treatment of epilepsy. In the National Institute of Neurology, monitoring has been performed using the technique chemiluminescent microparticle immunoassay (CMIA) in an automated way during the last five years. The aim of this study was to develop a simple and rapid HPLC analytical method coupled to DAD-UV detection for the determination of plasma concentrations of carbamazepine and compare its feasibility with those used in routine analysis. The developed HPLC method was fully validated and the applicability of the proposed method was verified through the analysis of plasma samples of patients and later compared with the quantification of the same plasma samples with the CMIA method. The limit of quantification obtained was 0.5 μg/mL. The mean value for recovery was 99.05% and the coefficient of variation (CV) was 5.6%. The precision and accuracy of this method were within the acceptable limits; inter- and intraday CV values were <10%. The correlation between the CMIA method and the developed HPLC method was very good (r ≈ 0.999). A Bland-Altman plot showed no significant bias between the results. The HPLC-DAD method may be an alternative to determine and monitoring the carbamazepine levels in human plasma or serum. Copyright