Nonsteroidal anti-inflammatory drugs enantioseparation

During an optimization phase in method development, the three factors in Table 2.3 were selected to develop the enantioseparation of a nonsteroidal anti-inflammatory drug (28). All examined factors were quantitative (A-C). 

The most extensive studies on molecular-imprinted polymers as stationary phases for enantioseparations were conducted using amino acids and their derivatives as the template, but many other classes of compounds have been studied, including peptides, p-blockers, and nonsteroidal anti-inflammatory drugs (see Table 3). Examples of separations are reported in Figs. 6-8. 

Chapter 9 is the last chapter in the first section of this book. Its intent is to draw the readers attention to the possible occurrence of specific cases when, in spite of the availability of most efficient tools to perform a successful enanti-oseparation, the goal cannot be obtained. Such bottlenecks occur, for example, in cases when one enantiomer, when dissolved in an ampholytic solvent, can easily and spontaneously change its steric configuration and undergo oscillatory transen-antiomerization in the course of its storage. In the first instance, observation of such behavior was made with selected chiral 2-arylpropionic acids (APAs) that are nowadays very common and in a wide use as nonsteroidal anti-inflammatory drugs (NS aids e.g., ibuprofen and naproxen). In the case of such compounds, both their enantioseparation and reliable densitometric quantification are questionable. 

Ibuprofen is a nonsteroidal anti-inflammatoiy drug (NSAID) used for pain relief due to the anti-inflammatory effects [56], however this drug has low solubility in aqueous solutions [57, 58], which implies involvement in negative absorption by the body. Then researchers are using supercritical fluid technology to overcome these drawbacks. Antonov et al., [59] studied the solubility of ibuprofen in supercritical CO2 by fourier transform infrared spectroscopy, moreover ibuprofen was also studied in supercritical impregnation processes polymers [60, 61], in theoretical RESS process [62, 63] and experimentally for micronization of particles with reductions from 45 pm to 2.85 pm [64], and formation of even smaller nanoparticles by RESOLV [65]. Furthermore, Molnar et al., [66] studied the enantioseparation of racemic ibuprofen in SFE and realized that the system pressure of the extraction is directly related to resolution efficiency. 

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