Determination of 5,10,15,20-tetra-(m-hydroxyphenyl)chlorin in human plasma by high performance liquid chromatography

Our plain-English summary of Determination of 5,10,15,20-tetra-(m-hydroxyphenyl)chlorin in human plasma by high performance liquid chromatography, by Q. Wang, H.B. Ris, H.J. Altermatt, et al (Biomedical Chromatography, 1993).

The study

• Authors: Q. Wang, H.B. Ris, H.J. Altermatt, B. Reynolds, J.C. Stewart, R. Bonnett, C.K. Lim
• Journal: Biomedical Chromatography
• Published: 1993;7(1):45-7
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A high performance liquid chromatographic method for the determination of the photodynamic chemotherapeutic agent 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (m-THPC) in human plasma following intravenous infusion is described. The procedure involves extraction of the drug in plasma with methanol/dimethyl sulphoxide (4:1 v/v) containing 5,10,15,20-tetra(p-hydroxyphenyl)chlorin as the internal standard and separation on a C18 reversed phase column with acetonitrile:0.1% trifluoroacetic acid (77:23 v/v) as the mobile phase. The drug was detected specifically and sensitively at its absorption maximum of 423 nm with a detection limit of 15 ng/mL (signal-to-noise ratio of 5). The intra- and inter-assay coefficients of variation (CV) on analysis of a plasma spiked with m-THPC (1 micrograms/mL) were 2.3 and 3.4% (n = 6), respectively.

In plain English

This was a laboratory methods paper, not a study of asbestos exposure or disease risk. The authors described a high performance liquid chromatography (HPLC) test for measuring m-THPC, an experimental light-activated (photodynamic) cancer drug, in human blood plasma. A related compound, p-THPC, was added to each sample as an internal standard for comparison. The test detected m-THPC down to 15 ng/mL in a 100 microlitre sample, and results were linear from 0.05 to 2 micrograms per mL. When known amounts of drug were added to plasma, mean recovery was 98.0% at 0.5 and 98.3% at 1.5 micrograms per mL. The figure for 1.0 is garbled in the scanned text. Repeat testing of plasma spiked with 1 microgram per mL varied by 2.3% within runs and 3.4% between runs. The authors applied the test to one patient with diffuse malignant mesothelioma who received 0.3 mg/kg of the drug intravenously. Plasma from that patient contained 125 ng/mL at 24 hours and 20 ng/mL at 120 hours. The authors concluded that the method was sensitive and specific for measuring m-THPC in plasma.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: laboratory analytical method development (HPLC assay for a drug in plasma), applied to samples from one patient
• Who was studied: plasma from one patient with diffuse malignant mesothelioma, plus spiked control plasma samples; place and dates of treatment not stated
• Exposure: No asbestos exposure was studied. The exposure was the photodynamic drug m-THPC, given intravenously at 0.3 mg/kg body weight over 15 minutes.
• Main results:
  • The internal standard p-THPC was added during extraction, and m-THPC was quantified from the ratio of its peak height to that of p-THPC
  • Detection limit was 15 ng/mL for a 100 microlitre plasma sample
  • Calibration was linear over 0.05 to 2 micrograms per mL, with a correlation coefficient of 0.9984
  • Mean apparent recovery from spiked plasma was 98.0 plus or minus 3.2% at 0.5 micrograms per mL and 98.3 plus or minus 3.6% at 1.5 micrograms per mL (n = 6 each). The 1.0 micrograms per mL value is garbled in the scan.
  • For control plasma spiked with 1 microgram per mL m-THPC, the intra-assay coefficient of variation was 2.3% and the inter-assay coefficient was 3.4% (n = 6)
  • The patient's plasma samples shown in Figure 3 contained 125 ng/mL and 20 ng/mL m-THPC
  • Those two patient samples were taken 24 hours and 120 hours after the drug was given
  • Haemin, an occasional plasma contaminant that interfered with an earlier solvent system, eluted at 25 minutes, well separated from the chlorins
• The authors' conclusion: The authors concluded that the method was sensitive and specific for measuring m-THPC in plasma and suited to monitoring drug levels and pharmacokinetic studies

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