scholarly journals Development and Validation of Liquid Chromatography-Based Methods to Assess the Lipophilicity of Cytotoxic Platinum(IV) Complexes

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 130 ◽  
Author(s):  
Matthias Klose ◽  
Sarah Theiner ◽  
Hristo Varbanov ◽  
Doris Hoefer ◽  
Verena Pichler ◽  
...  

Lipophilicity is a crucial parameter for drug discovery, usually determined by the logarithmic partition coefficient (Log P) between octanol and water. However, the available detection methods have restricted the widespread use of the partition coefficient in inorganic medicinal chemistry, and recent investigations have shifted towards chromatographic lipophilicity parameters, frequently without a conversion to derive Log P. As high-performance liquid chromatography (HPLC) instruments are readily available to research groups, a HPLC-based method is presented and validated to derive the partition coefficient of a set of 19 structurally diverse and cytotoxic platinum(IV) complexes exhibiting a dynamic range of at least four orders of magnitude. The chromatographic lipophilicity parameters φ0 and Log kw were experimentally determined for the same set of compounds, and a correlation was obtained that allows interconversion between the two lipophilicity scales, which was applied to an additional set of 34 platinum(IV) drug candidates. Thereby, a φ0 = 58 corresponds to Log P = 0. The same approaches were successfully evaluated to determine the distribution coefficient (Log D) of five ionisable platinum(IV) compounds to sample pH-dependent effects on the lipophilicity. This study provides straight-forward HPLC-based methods to determine the lipophilicity of cytotoxic platinum(IV) complexes in the form of Log P and φ0 that can be interconverted and easily expanded to other metal-based compound classes.

2021 ◽  
pp. 1-11
Author(s):  
Sultan M. Alshahrani ◽  
John Mark Christensen

This study was designed to develop and validate a simple and efficient high performance liquid chromatography (HPLC) method to determine flunixin concentrations in Asian elephant’s (Elephas maximus) plasma. Flunixin was administered orally at a dose of 0.8 mg/kg, and blood samples were collected. Flunixin extraction was performed by adding an equal amount of acetonitrile to plasma and centrifuging at 4500 rpm for 25 minutes. The supernatant was removed, and flunixin was analyzed using HPLC-UV detection. Two methods were developed and tested utilizing two different mobile phases either with or without adding methanol (ACN: H2O vs. ACN: H2O: MeOH). Both methods showed excellent linearity and reproducibility. The limit of detection was 0.05 ug/ml and limit of quantification was 0.1 ug/ml. the efficiency of flunixin recovery was maximized by the addition of methanol to mobile phase (ACN: H2O: MeOH as 50:30:20) at 95% in comparison to 23% without methanol. In conclusion, adding methanol to HPLC methods for extraction of flunixin from elephants’ plasma yielded higher recovery rate than without methanol.


INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (01) ◽  
pp. 35-40
Author(s):  
A. S. Bagde ◽  
V. V. Khanvilkar ◽  

The present work describes a validated reverse phase high performance liquid chromatography (RPHPLC) method for simultaneous estimation of dextromethorphan hydrobromide and quinidine sulphate in pharmaceutical dosage from. The drugs were resolved using Hemochrom Intsil C18-5U column (250×4.6) mm in isocratic mode with mobile phase methanol: water (0.08% diethylamine, 0.02% of glacial acetic acid and pH 4.4 adjusted with orthophosphoric acid) in the ratio of 70:30 V/V at a flow rate of 1.0 mL/min. Retention time of dextromethorphan hydrobromide and quinidine sulphate were 4.9±0.2 and 3.6±0.2, respectively, at 292nm. The above mentioned method was validated as per International Conference on Harmonization (ICH) guidelines. Linear responses were obtained in concentration ranges of 5-35 μg/mL for dextromethorphan hydrobromide and 4-16 μg/mL for quinidine sulphate, with correlation coefficient (r2) of 0.999 for both the drugs. A simple, selective, accurate, precise, robust and reliable RP-HPLC method thus developed and validated for simultaneous estimation of dextromethorphan hydrobromide and quinidine sulphate.


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