Enantiomer pindolol

Mass spectrometry (MS) is also being used to add another dimension of analysis to achiral-chiral analysis. Recently, an achiral-chiral column-switching LC/LC-MS/MS method was reported for the pindolol enantiomers in human serum (Motoyama et al., 2002) and phenprocoumon metabolites (Kammerer et al., 1998). For analytes that have very poor chromophores or cannot naturally fluoresce, MS detection can be more sensitive for the underivatized form of the analyte. Also, MS detection can be particularly useful when very similar analytes that differ in mass (such as some amino acids and metabolites) cannot be satisfactorily separated chromatographically,... 

Motoyama, A., Susuki, A., Shirota, O., Namba, R. (2002). Direct determination of pindolol enantiomers in human serum by column-switching LC-MS/MS using a phenylcarbamate 3-cyclodextrin chiral column. J. Pharm. Biomed. Anal. 28, 97-106. 

Cimetidine not only reduces the metabolism of beta-blockers such as propranolol, it is also known to act as an inhibitor of tubular secretion of a number of organic cations. Therefore it is not surprising to see that the renal clearance of pindolol is substantially and stereoselectively reduced by coadministration of this drug [59]. The administration of 400 mg cimetidine twice a day for 2 days before and 2 days after pindolol administration resulted in 26% and 34% reductions in the renal clearances of S(—)- and R(-t-)-pindolol, respectively. Therefore the plasma concentrations of the R(-l-) enantiomer increased more drastically (47%) than those of the S(—) enantiomer (38%) in the presence of cimetidine [59]. Because renal clearance accounts for only 50% of pindolol elimination, the significant increases in the plasma concentrations of pindolol enantiomers as a result of cimetidine coadministration cannot be explained from the inhibition of its renal clearance only. Apparently, cimetidine also reduces the metabolism of pindolol. 

Pindolol enantiomers separated on C-8 silica gel (Figure 3.7) were quantified by densitometry [52]. Samples and standards (9 pil) were applied by means of a Linomat IV instrument (Camag) in 5 mm bands, developed as described in Section 3.4.2, and scanned at 256 nm in the absorbance mode with a slit 4 mm long and 3 mm wide (aliquot scanning method). To determine the amount of each enantiomer in each band of a drug substance or dosage form, the assay utilized... 

The separation of pindolol enantiomers, a nonselective j8-adrenergic antagonist, by chemical derivatization with sugar-based derivatizing agent is reported [76]. 

Spell, J.C. and Stewart, J.T., A high-performance thin-layer chromatographic assay of pindolol enantiomers by chemical derivatization, J. Planar Chromatogr., 10, 222, 1997. 

Analytical Properties Separation of bopindolol and also separation of pindolol after derivatization with isopropyl isocyanate separation of dl mixtures of enantiomers can be used on both the analytical and preparative scales changes in pH will cause this phase to leach from the column storage at 4°C is recommended Reference 1,2... 

Steuer et al. demonstrated the use of supercritical fluid chromatography in the separation of enantiomers of 1,2 amino alcohols, namely pindolol, metoprolol, oxprenolol, propranolol, and DPT 201-106 using ionpairing modifiers [21]. The mobile phase consisted of carbon dioxide mixed with acetonitrile containing triethylamine as a counterion and /V-benzo-xycarbonylglycyl-L-proline as a chiral counterion. They found that the ca-... 

Pure enantiomer imprinting of L-phenylalanine anilide, (/ )-propranolol, S)-metoprolol and (50-ropivacaine has been undertaken and these MIP capillaries have been used in the CEC mode for enantiomer separations [39-41,60-62,70,71] (Table 16.1). Baseline separations for the enantiomers of phenylalanine (Fig. 16.7) and for propranolol and metoprolol could be carried out in less than 2 min. (Fig. 16.5). A propranolol column was shown to be able to resolve several other j8-blockers, including prenalterol, atenolol, pindolol, etc. (Fig. 16.8) [41] and the ropi-... 

Possible mechanisms responsible for this stereoselective renal clearance of pindolol appear to be stereoselective renal metabolism or stereoselective renal secretion (stereoselective binding to plasma proteins was not observed). Recently, Somogyi et al. investigated the effect of coadministration of dmetidine on the renal clearance of the two enantiomers of pindolol (58). Cimetidine significantly reduced the renal clearance of both enantiomers, but reduced the renal clearance of the R enantiomer by a greater extent than the S enantiomer. These data are consistent with the stereoselective renal elimination mechanism for pindolol, with the S enantiomer being preferentially cleared. 

In functional models the (S)-(-)-enantiomers of propanol, pindolol, penbutolol (levopenbutolol) and tertatolol behave as antagonists at both pre- and postsynaptic 5-HT1A receptors [3,69,70]. 

Jeppsson, A.B. Johansson, U. Waldeck, B. Steric aspects of agonism and antagonism at beta-adrenoceptors experiments with the enantiomers of terbutaline and pindolol. Acta Pharmacol. Toxicol. (Copenh) 1984, 54, 285-291. 

Whereas chloroform [722, 723] and 1,2-dichloroethane [733, 739] have been used extensively as mobile phase modifiers in the separation of enantiomers, they can also be used as the major mobile phase constituent. For example, chloroform-and DCM-based mobile phases were used to separate the enantiomers of the W-3,5-dinitrobenzoyl-iJf-amino phosphonates of metoprolol, oxprenolol, propanolol, pronethalol, pindolol, and bufriralol [796]. An (/ )-Af-(3,5-dinitrobenzoyl)phenylgly-... 

A partial separation of racemic pindolol was achieved with cellulose 3,5-dimethylphenylcarbamate (7.5 mg/mL) in a MIBK-phosphate buffer pH 7.0 solvent system. A slightly better separation was obtained for warfarin enantiomers using amylose 3,5-dimethylphenylcarbamate (7.6 mg/mL) in a MTBE-phosphate buffer pH 9.0. However, racemates such as propranolol, structurally close to pindolol, naproxen, and DNB-( )-Leu, which were easily resolved in HPLC using... 

Enantiomers of phenylpropanolamine, octopamine, pindolol, norphenyl-ephedrine, propanolol, and isoproterenol were separated with Rf differences of 0.05-0.24 by development of Whatman HP-KF HPTLC plates with dichloro-methane/methanol (75 25) containing different amounts of A-benzoxycarbonyl (BOC)-alanyl-L-proline (ZAP), BOC-isoleucyl-L-proline (ZIP), BOC-L-proline (ZP), BOC-glycyl-L-proline (ZGP), (lR)-(—)-ammonium-10-camphorsulfonate (CSA), and triethylamine (TEA). Visualization was under 254 nm UV light [29]. 

C-8F HPTLC layers (Merck) developed with 24 ml of water/isopropanol (70 30 + 0.3 g NaCl) in a saturated chamber served to separate pindolol isomers that were derivatized using 2,3,4,6-tetra-0-acetyl-j8-D-glucopyranosylisothiocyanate (GITC). Detection was carried out by densitometric scanning of UV absorbance (Scanner II Camag, Wilmington, NC, USA). The separation of the enantiomers is shown in Figure 3.7. Quantification of the enantiomers is described in Section 3.5.2 [52]. 

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