Table 8.
Techniques used for quantifying colistin in plasma.
| Technique | Methodology | Results | Ref |
|---|---|---|---|
| Microbiological bioassays | Quantifying colistin in human plasma using E. coli as indicator organism | Bioassays have mainly been used regarding clinical samples—evaluating urine and serum samples—less sensitive and specific tests | [100] |
| Fourier-transform infrared spectroscopy (FTIR) | Direct quantification of colistin methanesulfonate by attenuated total reflectance (ATR) FTIR | FTIR has enabled colistin to be detected in human plasma but must be complemented with other techniques, such as HPLC | [32] |
| High-resolution liquid chromatography (HPLC) | HPLC validation using fluorescence detection assay for quantifying colistin in plasma samples from hospitalised patients | A C18 column has been used with a mobile phase consisting of acetonitrile and water having a shorter retention time. Furthermore, this method has successfully quantified total colistin in plasma from patients treated with CMS | [30] |
| Quantifying colistin in plasma from Pseudomonas aeruginosa-infected mice | Accuracy and reproducibility have ranged from 10.1% to 11.2% with rat and urine plasma, respectively. Several antibacterial agents which have often been administered together have not interfered with the assay | [104] | |
| HPLC with evaporative light scattering detector (ELSD) | Quantifying colistin in plasma by HPLC with an ELSD | The method has proved to be specific, accurate, precise and linear | [105] |
| Diode array HPLC detector | Quantifying colistin in animal plasma by HPLC with diode array detector | Scanning in the UV 200-380 nm range, 206 and 208 nm wavelengths have enabled colistin to be quantified | [106] |
| Liquid chromatography mass spectrometry (LC-MS) | Routine quantification of colistin A and B and their respective CMS A and CMS B prodrugs in human plasma and urine | Pre-validation studies have demonstrated CMS stability in biological samples and extracts, this being a key point regarding reliable quantification of colistin and CMS. The assay has proved precise/accurate and reproducible for quantifying colistin A and B and CMS A and B in plasma samples | [102] |
| Ultra-performance liquid chromatography-electrospray tandem mass spectrometry with electrospray ionisation (UPLC-ESI-MS/MS) | Quantifying colistin in human plasma by a combination of techniques UPLC-ESI- MS/MS | Validation results have shown that the method had suitable selectivity and sensitivity. The method has been successfully used with plasma samples from cystic fibrosis patients who have been treated with colistin. The PK profile has been calculated. | [107] |