A non-cannabinoid immunogen used to elicit antibodies with broad cross-reactivity to cannabinoid metabolites.

A benzpyran derivative was linked to the lysines of bovine thyroglobulin (BTG) where 69% of the available lysines were modified. This derivative was designed to elicit antibodies that were directed towards the conserved epitopes of cannabinoid metabolites that appear in urine. Polyclonal antibodies from sheep and goats and murine monoclonal antibodies were generated using this immunogen. The cross-reactivity of the antibodies was compared with antibodies generated from the more traditional phenolic-linked or 9-linked immunogens. An ELISA assay was developed using delta 9-11-nor-9-carboxy-tetrahydrocannabinol (COOH-THC) to obtain a standard curve. The antibodies generated using the benzpyran immunogen showed an average of two to three times higher cross-reactivity towards 11-OH-delta 9-THC, 8 beta-OH-delta 9-THC, 8 alpha-OH-delta 9-THC, 11-OH-delta 8-THC, and 8 beta,11-di-OH-delta 9-THC than antibodies that were generated by traditional cannabinoid immunogens. The selectivity of the benzpyran-elicited antibodies was also compared with antibodies derived from traditional immunogens using clinical urine samples that were confirmed for cannabinoids by GC/MS. The total cross-reactive cannabinoid values obtained with the benzpyran-elicited antibodies were 49% higher than the values obtained using the traditional immunogen structures. The benzpyran immunogen-induced antibodies exhibited the same low cross-reactivity for non-structurally related compounds as antibodies derived from traditional immunogens. The novel benzpyran immunogen used in this study is the first non-cannabinoid immunogen used to generate cannabinoid-selective antibodies and demonstrates the usefulness of such a structure in developing broadly cross-reactive cannabinoid antibodies.

Analysis of lidocaine on the COBAS INTEGRA.

A new fluorescence polarization (FP) immunoassay was developed for the COBAS INTEGRA to quantitate lidocaine in serum and sodium heparin derived plasma. The COBAS INTEGRA, a random and continuous access clinical analyzer, performs the new lidocaine assay at a throughput of 300 tests per hour. Comparison studies with the Abbott TDx Lidocaine assay yielded a correlation coefficient of 0.99 and a regression value of INTEGRA = -0.01 + 0.95 TDx, n = 69. The assay was found to be linear throughout the concentration range of 0 to 10 micrograms/ml using CASCO STANDARDS's DOCUMENT TDM 1 Linearity Test Set and the COBAS-FP TDM Calibration Verification Test Set. The new lidocaine assay exhibited good precision as determined by the National Committee for Clinical Laboratory Standards (NCCLS) protocol EP5-T2 with total percent coefficient of variation (%CV) values of less than 4 percent across the assay range. Interference was less than 10 percent for abnormal levels of total protein (2.1 to 10 g/dl), lipid (up to 2200 mg/dl triglyceride), hemoglobin (up to 10 g/dl), and icteric samples (up to 17.5 mg/dl bilirubin). Finally, the standard curve was stable for greater than 25 weeks which was attributable to the on-board reagent cooling and a unique cassette closure system.

Self-induced nonequivalence in the 1H-NMR spectra of the (+)- and (-)-isomers of a cannabinoid ketone intermediate.

The 1H-NMR spectra in deuteriochloroform of racemic and optically pure (trans)-6a,7,10,10a-tetrahydro-1-hydroxy-6,6-dimethyl-3-pentyl-6H-dibenz o [b,d]pyran-9(8H)-one (1) are nonsuperimposable, while nonracemic mixtures of the (+)- and (-)-isomers show two sets of signals for the phenolic and aromatic protons in ratios directly proportional to the enantiomeric composition of the mixture. This is a new example of "self-induced nonequivalence" or "diastereomeric solute-solute interaction," a known but seldom reported phenomenon. The magnitude of the chemical shift differences are dependent on the ratios of the two enantiomers while the chemical shift delta values are concentration dependent. The overall effect was clearly observable even at a concentration of 0.01 M. In a practical sense, optical purities of samples of the cannabinoid ketone (1) are readily determined by 1H-NMR without the use of additional chiral shift reagents.