Simulated Moving-bed Adsorption For Separation Of Racemic Mixtures

The two enantiomers that constitute a racemate have different activities when employed as pharmaceuticals. Due to this fact, fully recognized today, the pharmaceutical industry has been forced to market pure enantiomers instead of the racemic mixture whenever a chiral compound is involved. The simulated moving bed (SMB) is a chromatographic process that, unlike traditional HPLC systems, operates continuously without losing the enantiomeric purity of the outlet streams. The present work describes the enantioseparation of the anesthetic ketamine in a semipreparative-scale SMB unit. The chiral stationary phase employed was the microcrystalline cellulose triacetate. The outlet streams were analyzed by an on-line system, composed by an UV/VIS meter and a polarimeter, and also by HPLC. The analysis indicated purity values up to 100% for the stream of interest and up to 97.7% for the other stream.211127136Blaschke, G., Chromatographic resolution of chiral drugs on polyamides and cellulose triacetate (1986) Journal of Liquid Chromatography, 9 (2), pp. 341-368Cass, Q.B., Degani, A.L.G., Tiritan, E., Matlin, S.E., Curran, D.P., Balog, A., Enantiomeric resolution by HPLC of axial chiral amides using amylose tris((S)-1-phenylethylcarbamate) (1997) Chirality, 9, pp. 109-112Francotte, E.R., Wolf, R.M., Lohmann, D., Muller, R., Chromatographic resolution of racemates on chiral stationary phases. I. Influence of the supramolecular structure of cellulose triacetate (1985) Journal of Chromatography, 345, pp. 25-37Juza, M., Mazzotti, M., Morbidelli, M., Simulated moving bed and its application to chiraltechnology (2000) Trends in Biotechnology, 18, pp. 108-118Lodevico, R.G., Bobbit, D.R., Edkins, T.J., Determination of enantiomeric excess using a chiral selective separation mode and polarimetric detection (1997) Talanta, 44, pp. 1353-1363Mazzotti, M., Storti, G., Morbidelli, M., Optimal operation of simulated moving beds for nonlinear chromatographic separations (1997) Journal of Chromatography A, 769, pp. 3-24McCoy, M., SMB emerges as a chiral technique (2000) Chemical and Engineering News, 78 (25), pp. 1-3Nicoud, R.M., A packing procedure for high flow rate and high stability columns using cellulose triacetate (1993) LC - GC Int., 6, pp. 636-637Nicoud, R.M., The separation of optical isomers by simulated moving bed chromatography (Part II) (1999) Pharmaceutical Technology Europe, 11, pp. 28-34Pedeferri, M.P., Zenoni, G., Mazzotti, M., Morbidelli, M., Experimental analysis of a chiral separation through simulated moving bed chromatography (1999) Chemical Engineering Science, 54, pp. 3735-374

Assessment of plasma chitotriosidase activity, CCL18/PARC concentration and NP-C suspicion index in the diagnosis of Niemann-Pick disease type C: A prospective observational study

Background: Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive neurodegenerative disease caused by mutations in either the NPC1 or NPC2 genes. The diagnosis of NP-C remains challenging due to the non-specific, heterogeneous nature of signs/symptoms. This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C-C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C. Methods: In a prospective observational cohort study, incorporating a retrospective determination of NP-C SI scores, two different diagnostic approaches were applied in two separate groups of unrelated patients from 51 Spanish medical centers (n = 118 in both groups). From Jan 2010 to Apr 2012 (Period 1), patients with =2 clinical signs/symptoms of NP-C were considered ''suspected NP-C'' cases, and NPC1/NPC2 sequencing, plasma chitotriosidase (ChT), CCL18/PARC and sphingomyelinase levels were assessed. Based on findings in Period 1, plasma ChT and CCL18/PARC, and NP-C SI prediction scores were determined in a second group of patients between May 2012 and Apr 2014 (Period 2), and NPC1 and NPC2 were sequenced only in those with elevated ChT and/or elevated CCL18/PARC and/or NP-C SI =70. Filipin staining and 7-ketocholesterol (7-KC) measurements were performed in all patients with NP-C gene mutations, where possible. Results: In total across Periods 1 and 2, 10/236 (4%) patients had a confirmed diagnosis o NP-C based on gene sequencing (5/118 4.2%] in each Period): all of these patients had two causal NPC1 mutations. Single mutant NPC1 alleles were detected in 8/236 (3%) patients, overall. Positive filipin staining results comprised three classical and five variant biochemical phenotypes. No NPC2 mutations were detected. All patients with NPC1 mutations had high ChT activity, high CCL18/PARC concentrations and/or NP-C SI scores =70. Plasma 7-KC was higher than control cut-off values in all patients with two NPC1 mutations, and in the majority of patients with single mutations. Family studies identified three further NP-C patients. Conclusion: This approach may be very useful for laboratories that do not have mass spectrometry facilities and therefore, they cannot use other NP-C biomarkers for diagnosis