18717-72-1Relevant articles and documents
Catalyzation of cocaine N-demethylation by cytochromes P4502B, P4503A, and P4502D in fish liver
Arinc, Emel,Bozcaarmutlu, Azra
, p. 169 - 176 (2003)
Cocaine N-demethylation by microsomal cytochrome P450s is the principal pathway in cocaine bioactivation and hepatotoxicity. P450 isozymes involved in N-demethylation of cocaine have not been elucidated yet and they differ from species to species. In humans and mice, P4503A contributes to cocaine N-demethylase activity, whereas in rats, both P4503A and P4502B participate. In the present study, contribution of different P450 isozymes to cocaine N-demethylase activity was studied in vitro with fish liver microsomes. The specific cocaine N-demethylase activity was found to be 0.672 ± 0.22 nmol formaldehyde formed/min/mg protein (mean ± SD, n = 6). Cocaine N-demethylase exhibited biphasic kinetics, and from the Lineweaver-Burk plot, two Km values were calculated as 0.085 and 0.205 mM for the high- and low-affinity enzyme. These results indicate that N-demethylation of cocaine in mullet liver microsomes is catalyzed by at least two cytochrome P450 isozymes. Inhibitory effects of cytochrome P450 isozyme-selective chemical inhibitors, ketoconazole, cimetidine, SKF-525A, and quinidine, on cocaine N-demethylase activity were studied at 50, 100, and 500 μM concentrations of these inhibitors. At 100 μM final concentrations, ketoconazole (P4503A inhibitor), SKF-525A (inhibitor of both P4502B and P4503A), and cimetidine (P4503A inhibitor) inhibited N-demethylation activity by 73, 69, and 63%, respectively. Quinidine, P4502D-specific inhibitor, at 100 μM final concentration, reduced N-demethylation activity down to 64%. Aniline, a model substrate for P4502E1, did not alter N-demethylase activity in the final concentration of 100 μM. IC50 values were calculated to be 20 μM for ketoconazole, 48 μM for cimetidine (both specific P4503A inhibitors), 164 μM for quinidine (P4502D inhibitor), and 59 μM for SKF-525A (inhibitor of both P4503A and P4502B). The contribution of P4502B to cocaine N-demethylase activity in mullet liver microsomes was further explored by the use of purified mullet cytochrome P4502B in the reconstituted system containing purified mullet P450 reductase and lipid. The turnover number was calculated as 4.2 nmol HCOH/(min nmol P450). Overall, these results show that P4503A and P4502B are the major P450s responsible for N-demethylation of cocaine, whereas contribution of P4502D is a minor one, and P4502E1 is not involved in the N-demethylation of cocaine in mullet liver microsomes.
NOVEL COCAINE HAPTENS AND NANOFIBER-BASED COCAINE VACCINES
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Sheet 11 of 14, (2017/09/06)
Certain embodiments are directed to chemically defined self-adjuvanting cocaine vaccines composed of novel cocaine haptens and self-assembling peptide domains.
Induction of protective and specific antibodies against cocaine by intranasal immunisation using a glyceride adjuvant
Hrafnkelsdottir, Kolbrun,Valgeirsson, Jon,Gizurarson, Sveinbjorn
, p. 1038 - 1042 (2007/10/03)
The goal of this study was to investigate an intranasal cocaine vaccine containing the mucosal adjuvant macrogol-6-glycerol capylocaprate (RhinoVax). Cocaine-KLH conjugate was prepared and administered in two formulations. Ten mice were immunised intranasally using RhinoVax as adjuvant and ten subcutaneously using aluminium hydroxide as an adjuvant. A negative control group (n=10) received unconjugated KLH with RhinoVax intranasally. Specific cocaine antibodies in serum were measured following primary and booster immunisation. Relative antibody responses in serum indicated that the immunisation was successful. Animals were then challenged with cocaine either intranasally or intraperitoneally with subsequent measurement of drug distribution into the serum, brain and olfactory bulb. The cocaine-immunised groups revealed significantly lower cocaine levels in the brain compared to the negative control group. The inhibition of cocaine distribution to the brain in the intranasal immunised group was comparable to that of the subcutaneous immunised group. This was unexpected because the cocaine specific antibody levels in serum were fivefold lower in the intranasal immunised group. However, the presence of mucosal cocaine specific antibodies after intranasal immunisation could play an important role in hindering direct access of cocaine into the brain via the olfactory bulb.