Dynamic and Static Characteristics of Drug Dissolution in Supercritical CO2 by Infrared Spectroscopy: Measurements of Acetaminophen Solubility in a Wide Range of State Parameters
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.
Compounds
#
Formula
Name
1
C8H9NO2
N-acetyl-p-aminophenol
2
CO2
carbon dioxide
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.
Type
Compound-#
Property
Variable
Constraint
Phase
Method
#Points
POMD
1
2
Mole fraction - 1 ; Fluid (supercritical or subcritical phases)
Temperature, K; Fluid (supercritical or subcritical phases)
Pressure, kPa; Fluid (supercritical or subcritical phases)