Local anaesthetics separation

Fig. 8-85. Analysis of sulfite in a local anaesthetics. — Separator column IonPac AS9 eluent 0.00075 mol/L NaHC03 + 0.002 mol/L Na X flow rate 2 mL/min detection suppressed conductivity injection 50 pL sample (diluted 1 10).

Bhole MV, Manson AL, Seneviratne SL, Misbah SA. IgE-mediated allergy to local anaesthetics separating fact from perception a UK perspective. Br J Anaesth2012 108(6) 903-ll. 

Sanger-van de Griend et al. (29) determined the binding constants of several local anaesthetics with DM-/3-CD. These data showed that the achiral separation of analogues is a result of their mobility difference, whereas the resolution of enantiomers results from the difference in their binding constants with CDs. 

CE Sanger-van de Griend, K Groningsson, D Westerlund. Chiral separation of local anaesthetics with capillary electrophoresis. Evaluation of the inclusion complex of the enantiomers with hcptakis(2,6-di-0-methyl)-/3-cyclodextrin. Chromatographia 42 263-268, 1996. 

EM Javerfalk, A Amini, D Westerlund, PE Andren. Chiral separation of local anaesthetics by a capillary electrophoresis/partial-filling technique coupled online to micro-electrospray mass spectrometry. J Mass Spectrom 33 183-186, 1998. 

Separation of the enantiomers of a series of local anaesthetics through their interaction with dimethyl p-cyclodextrin included In the running buffer. Redrawn from Reference 6. 

Figure 14.11 shows the separation of R and S isomers of a series of structurally related local anaesthetics. Wide separations were achieved for the compounds in this series where it was proposed that the fit of the hydrophobic portion of the analyte into the cyclodextrin was optimal when one of the substituents at the chiral centre was able to interact with the chiral hydroxyl groups on the rim of the cyclodextrin cavity. Table 14.3 shows the association constants calculated for the interaction of the enantiomeric pairs with the dimethylcyclodextrin. The larger the value of K, the... 

Unconscious patients are usually catheterised and, in this case, the sample may be contaminated with the catheter lubricant which frequently contains lignocaine as a local anaesthetic. Urine is ideal for qualitative screening as it is available in large volumes, and usually contains higher concentrations of drugs or poisons than blood. The presence of drug metabolites can be used to assist identification if chromatographic techniques which can separate them are used. A 50-ml sample is sufficient for a comprehensive series of tests, and no preservative should be added. 

Amin and Jakobs48) dissolve suppositories and ointments, which contain several active ingredients (hydrocortisone or its esters, an antihistaminic, a local anaesthetic and a disinfectant), in chloroform/methanol. They apply the solution directly on a thin-layer plate without freeing it from the suppository or ointment base. After the separation the active ingredients are scanned with variation coefficients of 1.29-3.56%. 

Coc,various drugs of abuse(Table 7.8) Local anaesthetics, vari ous other drugs Separation drugs of abuse... 

One consisted of a mobile phase of methanol - water - U acetic acid (40 59 1) containing 0.02 M methanesulfonic acid (pH 3.5) in combination with a microparticulate octadecyl column. It was recommended for samples containing compounds such as barbiturates, local anaesthetics, LSD and related alkaloids. The other system made use of the same column and a mobile phase of methanol - water - 1% acetic acid (20 79 1) containing 0.02 M methanesulfonic acid (pH 3.5). It was particularly suitable for the analysis of phenethylamines and for the separation of heroin and acetyl codeine. The increased counter-ion concentration in these mobile phases compared to previously used systems was applied to reduce the... 

It will be now worthwhile to elaborate and discuss the structure-activity relationship of certain specific examples of local anaesthetics vis-a-vis the aforesaid three separate zones imbeded into the drug molecule. 

Choudry NB, Fuller RW, Anderson N, Karlsson JA (1990) Separation of cough and reflex bron-choconstriction by inhaled local anaesthetics. Eur Respir J 3 579-583 Chuang HH, Prescott ED, Kong H, Shields S, Jordt SE, Basbaum AI, Chao MV, Juhus D (2001) Bradykinin and nerve growth factor release the capsaicin receptor from PtdIns(4,5)P2-mediated inhibition. Nature 411 957-962... 

Choudry NB, Fuller RW, Anderson N, Karlsso JA (1990) Separation of cough and reflex bron-choconstriction by inhaled local anaesthetics. Eur Respir J 3 579-583... 

Schweitz, L. Andersson, L.I. Nilsson, S. Capillary electrochromatography with molecular imprint-based selectivity for enantiomer separation of local anaesthetics. J. Chromatogr. A 1997, 792, 401 09. 

RusticheUi, C. Ferioh, V. Gamberini, G. Stancanelli, R. Enantiomeric separation of local anaesthetic drug by HPLC on chiral stationary phases, Chromatographia, 2001,54, 731-736. 

Local anaesthetics, such as procaine, which are stronger bases may be completely separated from cocaine by the extraction of the latter with light petroleum in sodium bicarbonate solution by the method of Nicholls (above). Permanganate oxidation, as described on p. 186, completely destroys these local anaesthetics, no extractable matter being obtained. Orthocaine is also phenolic and not removed from solution in sodium hydroxide but easily from sodium bicarbonate solution. The base is very weak and salts are hydrolysed in solution, so that much of it can be extracted in acid solution. 

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