Acidic drugs reversed-phase liquid

Kampo medicines in which A.fangchi root or A. manshuriensis stem may be misused [492], Moreover, LC-PDA and LC-EIMS detection methods both were effective in distinguishing AAI (5) and AAII (5) peaks by their spectra. Very recently, we have reported the extensive analysis of aristolochic acids and aristolactams in the various Chinese medicinal plants and crude drugs using different techniques. A method has been developed using reversed phase liquid chromatography coupled with atmospheric pressure chemical ionization (APCI) tandem mass spectrometry under the positive ion detection mode [LC/(+)APCI/MS/MS] to determine the amount of AA-1(5) in Xinxin, a traditional Chinese medicine that originate from nine Asarum species... 

T. Hanai, R. Miyazaki, A. Koseki and T. Kinoshita, Computational chemical analysis of the retention of acidic drugs on a pentyl-bonded silica gel in reversed-phase liquid chromatography,/. Chramatagr. Set, 2004, 42, 354-360. 

For the QSRR of reversed-phase liquid chromatography, the contact surface area is important, and the selection of a model phase is difficult, but a simple model phase is satisfactory for the measurement of albumin-acidic drug binding affinity in ion-exchange liquid chromatography/ ... 

Further analysis was performed to estimate the albumin-acidic drug binding affinity log oRT values. The albumin-acidic drug binding affinity was measured at pH 7.40. The log k values measured at pH 7.40 correlated with the predicted log tiK" values from the literature. The following relationship was obtained, log tiK = 1.597 x(log A )+ 5.808, r= 0.887, n = 13. The log nAT values may be derived from log k values measured on a guanidino phase at pH 7.40. Therefore, the addition of k measured by reversed-phase liquid chromatography improved the correlation, as previously described. ... 

Gustavo Gonzalez, Strickley A. Practical digest for the evaluation of acidity constants of drugs by reversed phase high performance liquid chromatography. Int J Pharm 1987 91 R1-R5. 

Theodoridis, G. Papadoyannis, I. Vasilikiotis, G. Tsoukali-Papadopoulou, H. Reversed-phase high-performance liquid chromatography-photodiode-array analysis of alkaloid drugs of forensic interest. J.Chromatogr.B, 1995, 668, 253-263 [also amphetamine, bamifylline, caffeine, cocaine, codeine, dia-morphine, ethylmorphine, flufenamic acid, methadone, morphine, nalorphine, norcodeine, papaverine, quinine, scopolamine, strychnine, theobromine, theophylline, tolfenamic acid]... 

A column liquid chromatographic method for the simultaneous determination of chloroquine, amodiaquine and their monodesethyl metabolites in human plasma, red blood cells, whole blood and urine has been developed (41). The drugs and internal standards are extracted as bases with dichloromethane and then re-extracted into an acidic aqueous phase. Separation is achieved using a reversed-phase column and a mobile phase of phosphate buffer (pH 3.0) methyl cyanide (88 12). The absorbance of the drugs is monitored at 340 nm with a sensitivity limit of 10 pmol/ml. The mean overall recovery from each biological fluid is more than 75%. This method can be applied to therapeutic, pharmacokinetic, and epidemological studies. 

Figure 9.3 The relationship between log nK and log k values measured by reversed-phase and ion-exchange liquid chromatography for acidic drugs.

---