The present study describes a rapid and effective capillary electrophoresis (CE) method for the enantioseparation of pindolol using single-isomer octa(6-O-sulfo)-γ-cyclodextrin. The complexation parameters were determined under neutral and high pH conditions to identify optimal separation conditions using a theoretical model. Baseline separation of pindolol enantiomers was achieved within 6 min in a sodium/MOPS buffer, pH 7.2, with a selector concentration of 6 mM. The method was validated according to the ICH guidelines using imidazole as an internal standard. Low limits of detection and quantification were found, specifically 1.2 μg/mL and 4 μg/mL (0.6 μg/mL and 2 μg/mL per enantiomer), respectively. The calibration curves showed good linearity, with a coefficient of determination R2 ≥ 0.999 over a 5 - 55 μg/mL concentration range and over a 50 - 300 μg/mL concentration range of the racemic mixture. The relative standard deviations (%RSD) of intra-day and inter-day precision were lower than 8% at LOQ level, lower than 3% at 50 μg/mL level and lower than 1.5% at 300 μg/mL level. Accuracy ranged from 95 to 103% (106% at LOQ level). The proposed method was successfully tested on a medical formulation of Visken® Sandoz intravenous solution and Visken® Teofarma pills for oral use.
- MeSH
- časové faktory MeSH
- elektroforéza kapilární metody MeSH
- gama-cyklodextriny chemie MeSH
- kalibrace MeSH
- koncentrace vodíkových iontů MeSH
- limita detekce MeSH
- pindolol izolace a purifikace MeSH
- pufry MeSH
- reprodukovatelnost výsledků MeSH
- software * MeSH
- stereoizomerie MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
A capillary electrophoresis method for the simultaneous determination of the enantiomeric purity and of impurities of the chiral calcimimetic drug cinacalcet hydrochloride has been developed following Quality by Design principles. The scouting phase was aimed to select the separation operative mode and to identify a suitable chiral selector. Among the tested cyclodextrins, (2-carboxyethyl)-β-cyclodextrin and (2-hydroxypropyl)-γ-cyclodextrin (HPγCyD) showed good chiral resolving capabilities. The selected separation system was solvent-modified capillary zone electrophoresis with the addition of HPγCyD and methanol. Voltage, buffer pH, methanol concentration and HPγCyD concentration were investigated as critical method parameters by a multivariate strategy. Critical method attributes were represented by enantioresolution and analysis time. A Box-Behnken Design allowed the contour plots to be drawn and quadratic and interaction effects to be highlighted. The Method Operable Design Region (MODR) was identified by applying Monte-Carlo simulations and corresponded to the multidimensional zone where both the critical method attributes fulfilled the requirements with a desired probability π≥90%. The working conditions, with the MODR limits, corresponded to the following: capillary length, 48.5cm; temperature, 18°C; voltage, 26kV (26-27kV); background electrolyte, 150mM phosphate buffer pH 2.70 (2.60-2.80), 3.1mM (3.0-3.5mM) HPγCyD; 2.00% (0.00-8.40%) v/v methanol. Robustness testing was carried out by a Plackett-Burman matrix and finally a method control strategy was defined. The complete separation of the analytes was obtained in about 10min. The method was validated following the International Council for Harmonisation guidelines and was applied for the analysis of a real sample of cinacalcet hydrochloride tablets.
- MeSH
- beta-cyklodextriny chemie MeSH
- cinakalcet chemie izolace a purifikace MeSH
- elektroforéza kapilární metody MeSH
- gama-cyklodextriny chemie MeSH
- hodnocení rizik MeSH
- koncentrace vodíkových iontů MeSH
- kontaminace léku MeSH
- metoda Monte Carlo MeSH
- pravděpodobnost MeSH
- rozpouštědla MeSH
- stereoizomerie MeSH
- Publikační typ
- časopisecké články MeSH
Herein we report on the synthesis, characterization and the novel capillary electrophoretic use of octakis-(2,3-di-O-methyl-6-O-carboxymethyl)-γ-cyclodextrin sodium salt (ODMCM). ODMCM is the first single-isomer carboxymethyl-γ-cyclodextrin that is fully methylated on its secondary side and carries ionizable carboxymethyl functions on its primary side. ODMCM was prepared with high isomeric purity through a four-step synthetic procedure. The purity of each intermediate was characterized by appropriate chromatographic methods, while the isomeric purity of the carboxymethylated product was determined by an HPLC method using a CD-Screen-IEC column and by a capillary electrophoretic method using indirect UV detection, as well. The structural identification of the ODMCM was carried out by 1D, 2D NMR spectroscopy and ESI-MS. The acid-base characterization of the chiral selector was carried out by (1)H NMR-pH titration. The chiral separation ability of the synthesized selector was studied by chiral capillary electrophoresis. ODMCM was used as a background electrolyte additive to separate enantiomers of representative pharmacologically significant model molecules such as propranolol, citalopram, ketamine, tapentadol and dapoxetine. The effects of the selector concentration and the pH of the background electrolyte on the enantiorecognition properties were investigated. (1)H NMR spectroscopy was further applied to get deeper insight of the host-guest inclusion complex formation. The pH-dependent enantioselectivity of this new single-isomer chiral selector was demonstrated by chiral capillary electrophoresis and (1)H NMR spectroscopy.
- MeSH
- elektroforéza kapilární * MeSH
- gama-cyklodextriny chemie MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací * MeSH
- indikátory a reagencie MeSH
- koncentrace vodíkových iontů MeSH
- magnetická rezonanční spektroskopie MeSH
- spektrofotometrie ultrafialová * MeSH
- stereoizomerie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
Per(2,3,6-tri-O-benzyl)-γ-cyclodextrin was debenzylated by DIBAL-H to produce a mixture of C6(I),C6(IV) and C6(I),C6(V) isomeric diols, which were separated and isolated. The C2-symmetrical C6(I),C6(V) diol was transformed into dithiol and dimerized to produce a γ-cyclodextrin duplex structure. A crystal structure revealed tubular cavity whose peripheries are slightly elliptically distorted. The solvent accessible volume of the cavity of the γ-CD duplex is about 740 Å(3). Due to this large inner space the duplex forms very stable inclusion complexes with steroids; bile acids examined in this study show binding affinities to the γ-cyclodextrin duplex in the range of 5.3 × 10(7) M(-1)-1.9 × 10(8) M(-1).
- MeSH
- dimerizace MeSH
- disulfidy chemie MeSH
- farmaceutická chemie metody MeSH
- gama-cyklodextriny chemická syntéza chemie MeSH
- imatinib mesylát chemie MeSH
- kalorimetrie MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- krystalografie rentgenová MeSH
- kyselina lithocholová chemie MeSH
- kyslík chemie MeSH
- magnetická rezonanční spektroskopie MeSH
- molekulární konformace MeSH
- rozpouštědla chemie MeSH
- steroidy chemie MeSH
- sulfhydrylové sloučeniny chemie MeSH
- termodynamika MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We report a chiral switch in the configuration of 1-(p-methoxyphenyl)-propan-2-ol, synthesized in aqueous media by ketoreductase in the presence of high concentration of gamma-CD. NMR, ECD and fluorescence spectrometry were used in the effort to explain this unexpected effect. A comparison has been made between the catalytic activity of the enzyme and alpha-helix content in the conformation and it has been observed that enzyme is most active at the maximum alpha-helix content. The beta-sheet content and random coil conformation in the enzyme were found to be dependent on cyclodextrin concentration.
- MeSH
- alkoholdehydrogenasa metabolismus MeSH
- alkoholoxidoreduktasy metabolismus MeSH
- cirkulární dichroismus MeSH
- fluorescenční spektrometrie MeSH
- gama-cyklodextriny chemie MeSH
- ketony chemie MeSH
- magnetická rezonanční spektroskopie MeSH
- oxidace-redukce MeSH
- stereoizomerie MeSH
- Thermoanaerobacterium enzymologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
