Bupivacaine separation

When using PFT with a neutral selector, it is quite difficult to avoid any entrance of the chiral selector into the ionization source, particularly at a high pH, where EOF is important. The use of BGE at low pH and/or coated capillary to minimize EOF is therefore mandatory. However, the coaxial sheath gas, which generally assists the ionization process, leads to an aspirating phenomenon of the chiral selector in the MS direction. Javerfalk et al. were the first to apply PFT with a neutral methyl-/i-CD for the separation of racemic bupivacaine and ropivacaine with a polyacrylamide-coated capillary and an acidic pH buffer (pH 3). Cherkaoui et al. employed another neutral CD (HP-/1-CD) with a PVA-coated capillary for the analysis of amphetamines and their derivatives. To prevent a detrimental aspiration effect, analyses were carried out without nebulization pressure. Numerous other studies presented excellent results such as the enantioselective separation of adrenoreceptor antagonist drugs using tandem mass spectrometry (MS/MS) the separation of clenbuterol enantiomers after solid-phase extraction (SPE) of plasma samples or the use of CD dual system for the simultaneous chiral determination of amphetamine, methamphetamine, dimethamphetamine, and p-hydroxymethamphetamine in urine. 

MIPs used as chiral stationary phases in o-CEC, p-CEC as well as in rod-CEC have shown high selectivity but relatively low efficiency. Most of the reported enantiomer separations on these phases were performed without pressurization of the flow system. Only Schweitz et al. described on the enantiomer separation of propranolol and metoprolol (print molecule R-propranolol or S-metoprolol) [57] and ropivacaine, mepivacaine and bupivacaine (print molecule S-ropivacaine) [58] by... 

Racemic bupivacaine hydrochloride (38, Marcaine) is currently used as an epidural anesthetic during labor and as a local anesthetic in minor operations. Clinical studies have shown that ei o-bupivacaine (41) is less car-diotoxic in man, making it significantly safer than the racemate (67). Separation of the enantiomers was readily achieved using 0.25 eq of D-tartaric acid. This resulted in the isolation of a 2 1 (S)-bupivacaine o-tartaric acid salt (39) in 98% de, leaving the (J2)-bupivacaine... 

Several neutral alkylglucoside surfactants, such as heptyl-, octyl-, nonyl-, and decyl-j8-D-glucopyrano-sides and octylmaltopyranoside, were also employed for the enantiomer separation of phenoxy acid herbicides, Dns-DL-AAs, l,r-bi-2-naphthyl-2,2 -diyl hydrogen phosphate (BNP), warfarin, bupivacaine, and so forth. 

Schill, G. Wainer, I.W. Barkan, S.A. Chiral separation of cationic drugs on an al-acid glycoprotein bonded stationary phase. J.Liq.Chromatogr, 1986, 9, 641-666 [chiral also bromdiphenhydramine, brompheniramine, bupivacaine, butorphanol, carbinoxamine, chlorpheniramine, clidinium, cocaine, cyclopentolate, dimethindene, diperidone, disopyramide, doxylamine, ephedrine, homatropine, labe-talol B, labetalol, labetalol A, mepensolate, mepivacaine, methadone, methorphan, methylatropine, methylhomatropine, methylphenidate, metoprolol, nadolol, nadolol A, nadolol B, oxprenolol, oxy-phencyclimine, phenmetrazine, phenoxybenzamine, promethazine, pronethalol, propoxyphene, propranolol, pseudoephedrine, terbutaline, tocainide, tridihexethyl]... 

Stereochemistry of the local anesthetics, however, plays an important role in their observed toxicity and pharmacokinetic properties. For example, ropivacaine and levobupivacaine, the only optically active local anesthetics currently being marketed, have considerably lower cardiac toxicities than their close structural analogue, bupivacaine (45). Furthermore, the degree of separation between motor and sensory blockade is more apparent with ropivacaine and levobupivacaine relative to bupivacaine at a lower end of the dosage scale (46). Thus, the observed cardiac toxicity of bupivacaine has been attributed to the F -( + )-bupivacaine enantiomer (41,42,43). The exact mechanisms for this enantiomeric... 

Chiral separation of bupivacaine Human serum albumin FSCE [156]... 

Martmez-Pla J.J., Martm-Biosca Y, Sagrado S., Villanueva-Camanas R.M., Medina-Hernandez M.J., Chiral separation of bupivacaine enantiomers by capillary electrophoresis partial-filling technique with human serum albumin as chiral selector. J. Chromatogr. A, 1048, 111-118 (2004). 

Wu YY, Li T, Liang H, Xue J (2005) Separation and determination of bupivacaine in plasma by capillary electrophoresis with tris(2,2 -bipyridyl)ruthenium(ll) electrochemiluminescence detection. Luminescence 20(4-5) 352-357. doi 10.1002/bio.855... 

Severe chronic pain is sometimes treated with co-administered ketamine/ bupivacaine. These compounds were isolated from plasma and analyzed on a cyanopropyl column (A = 215nm). A 718/220/80/2 water (lOmM NaH2p04 buffer at pH 2.34)/methanol/acetonitrile/H3P04 mobile phase generated baseline separation in <8 min. The peaks were quite tailed. Introduction of TEA and/or a TFA/triethylamine buffer syston in place of the phosphate system may remedy this. Calibration curves from 10 to 400ng/mL (ketamine) and 125 to 4000ng/mL (bupivacaine) were stated, with the lowest concentration serving as the quantitation limit. Detection limits (S/N = 4) of 1 ng injected and 0.8 ng injected, respectively, were reported [563]. 

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