Dynamic and static characteristics of drug dissolution in supercritical CO2 by infrared spectroscopy: measurements of acetaminophen solubility in a wide range of state parameters

Roman D. Oparin, Abdenacer Idrissi, Maxim V. Fedorov, Michael G. Kiselev

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In this work we use infrared spectroscopy to investigate solubility properties of a bioactive substance in supercritical CO2 (scCO2). By using acetaminophen as a model compound, we show that the method can provide high sensitivity that makes it possible to study solubility at small concentrations, up to 10-6 mol·L-1. This method also allows one to investigate the kinetics of the dissolution process in supercritical solvent. Our measurements at two different points of the (p, T) plane ((40 MPa, 373 K) and (40 MPa, 473 K)) have shown significant difference in the kinetic mechanisms of acetaminophen dissolution at these two states: at higher temperature the dissolution process in scCO2 has two steps: (i) "fast" step when the acetaminophen concentration in scCO2 quickly reaches (70 to 80) % of the saturation level and (ii) a subsequent "slow" step where the acetaminophen concentration slowly increases up to the saturation level. However, at lower temperature, the dissolution process has only one, "slow" step.

Original languageEnglish
Pages (from-to)3517-3523
Number of pages7
JournalJournal of Chemical and Engineering Data
Issue number11
Early online date23 Sep 2014
Publication statusPublished - 13 Nov 2014


  • carbon dioxide
  • infrared spectroscopy
  • solubility
  • acetaminophen solubilities
  • bioactive substances
  • dissolution process
  • lower temperatures
  • small concentration
  • solubility properties
  • static characteristic
  • supercritical solvents
  • bioactive molecules
  • scCO2
  • mechanisms of solvation
  • solubility of drugs

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