Chemometrics supported optimization of a multi-attribute monitoring liquid chromatographic method for estimation of palbociclib in its dosage form: Application to a new regulatory paradigm.

OBJECTIVE: The objective of present work was to develop a validated liquid chromatographic method for the estimation of palbociclib in its solid dosage forms by employing a new systematic concept. MATERIAL AND METHOD: Risk assessment and control measures were undertaken along with chemometrics assistance to establish the robust method performance for studied analytical attributes viz. analyte retention, resolution, plate number, and tailing factor. Methanol %, flow rate, and pH were found influential on the performance of studied analytical attributes and optimized using a Box-Behnken experimental design. Monte-Carlo simulation was performed to evaluate the performance of the analytical procedure. A multi-attribute monitoring liquid chromatographic method employing methanol: 0.01M KH2PO4 buffer of pH 3.5 (70:30, v/v) was used with a reversed-phase column. Flow rate at 1.2mL/min and detection at 265nm monitored peak responses. RESULT: The method efficiently separated analyte from the internal standard caffeine (resolution>16). Specificity (resolution>2.0), linearity (2-64µg/mL), accuracy (>99%) and precision (%RSD<1%) were well in accord with regulatory requirements. Further, analyte was detected at 1µg/mL and was stable over applied stress conditions. CONCLUSION: In a nutshell, the novel approach produced an accurate method for estimation of palbociclib in tablets with optimum method performance.

Evidence of isotopic fractionation of natural uranium in cultured human cells.

The study of the isotopic fractionation of endogen elements and toxic heavy metals in living organisms for biomedical applications, and for metabolic and toxicological studies, is a cutting-edge research topic. This paper shows that human neuroblastoma cells incorporated small amounts of uranium (U) after exposure to 10 µM natural U, with preferential uptake of the 235U isotope with regard to 238U. Efforts were made to develop and then validate a procedure for highly accurate n(238U)/n(235U) determinations in microsamples of cells. We found that intracellular U is enriched in 235U by 0.38 ± 0.13‰ (2σ, n = 7) relative to the exposure solutions. These in vitro experiments provide clues for the identification of biological processes responsible for uranium isotopic fractionation and link them to potential U incorporation pathways into neuronal cells. Suggested incorporation processes are a kinetically controlled process, such as facilitated transmembrane diffusion, and the uptake through a high-affinity uranium transport protein involving the modification of the uranyl (UO22+) coordination sphere. These findings open perspectives on the use of isotopic fractionation of metals in cellular models, offering a probe to track uptake/transport pathways and to help decipher associated cellular metabolic processes.