Development and validation of stability-indicating HPLC and UPLC methods for the determination of bicalutamide.

Six new process related impurities (Imp-08, Imp-09, Imp-10, Imp-12, Imp-13 and Imp-14) of bicalutamide (BCT) have been reported in this paper. BCT was subjected to oxidative, acid, alkaline, hydrolytic, thermal and photolytic degradation conditions and found to degrade in alkaline condition, yielding Imp-11. Stability-indicating high-performance liquid chromatography and ultra-performance liquid chromatography methods were developed for the determination of BCT in the presence of its 14 process-related impurities and 1 degradant by using Zorbax SB phenyl column (150 × 4.6 mm × 3.5 µm) and HSS T3 column (100 × 2.1 mm × 1.8 µm), respectively. Both the methods were validated as per International Conference on Harmonization guidelines. Quantitation limits (QL) were found be in the ranges of 0.02-0.03% for both the methods. Precision was evaluated by replicate analysis in which % relative standard deviation (RSD) values for areas were found below 2.0. Linearity for the impurities was established in the range of QL to 200% of the specification level and the correlation coefficients derived from of the respective calibration curves were approximately 0.999. The recoveries obtained for purity (90-100%) and assay (98-102%) ensured the accuracy of the developed methods.

Lipophilic benzamide and anilide derivatives as high-performance liquid chromatography internal standards: application to sirolimus (rapamycin) determination.

Finding a suitable internal standard in reversed-phase high-performance liquid chromatography is often difficult. A general approach for selecting and synthesizing the proper internal standard is presented and applied to a validated method for quantitation of sirolimus in several biological matrices. A series of fifteen N-alkylbenzamides, N-alkyltoluamides and N-alkanoylanilines with a log P range of 3.51 to 6.68 were synthesized as internal standards; N-undecyl-o-toluamide was evaluated most extensively. Sirolimus quantitation involves a simple sample clean-up procedure followed by isocratic chromatography on a heated C18 analytical column with an 70% methanol-water mobile phase and ultraviolet detection at 278 nm. This method was linear from 2.5 to 200 ng with a limit of quantitation of 2.5 ng using a 1-ml blood sample. Sirolimus recovery was above 72.1%. The intra-day and inter-day coefficients of variation were less than 11.7%. Several drugs and sirolimus metabolites do not interfere with the analysis. This method was used to measure sirolimus in blood from rats, rabbits and humans.