Enantiometric Separation Of Sitagliptin In A Fixed Dose Combination Formula Of Sitagliptin And Metformin By A Chiral Liquid Chromatographic Method

Objective: Sitagliptin phosphate and metformin hydrochloride tablet is an FDA approved combination product for the treatment of diabetes mellitus type 2. There are no reported evidence for estimation of undesired (S)-sitagliptin in a combination product. The objective of this study was to develop a high sensitive liquid chromatography method for the determination of (S)-enantiomer of sitagliptin phosphate in a fixed dose combination formula of metformin and sitagliptin. Methods: The proposed novel high-performance liquid chromatography (HPLC) method uses programmed gradient elution of a mixture of ethanol-diethylamine(DEA) 100:0.1 (v/v) as mobile phase-A and a mixture of methanol-water 60:40 (v/v) as mobile phase-B. The chromatographic conditions were designed to nullify the metformin interference and in which sitagliptin enantiomers elute first and followed by metformin. A satisfactory resolution (≥2.5) between (S)-sitagliptin and active form (R)-sitagliptin was achieved with gradient elution on Chiralpak IA column (5μm, 4 × 250 mm) at a flow rate of 0.5 ml/min and the detector wavelength set at 265 nm. The injection volume set as 10 µl. The developed method has been validated as per the International Conference on Harmonisation (ICH) guidelines. Results: The proposed HPLC method for determination of (S)-sitagliptin, showed good linearity in the concentration range of 0.5 µg/ml to 13.6 µg/ml and capable to quantify accurately up to the lowest level (LOQ) of 0.017%. The validated method was successfully applied to quantify the (S)-sitagliptin for different marketed formulations of sitagliptin with metformin and sitagliptin alone, and the corresponding recovery values were found to be in the range of 95.1% to 98.4%. Conclusion: The proposed validated HPLC method was found to be suitable for the quantitative determination of (S)-sitagliptin in the formulations of sitagliptin with metformin and sitagliptin alone.

Screening primary racemic amines for enantioseparation by derivatized polysaccharide and cyclofructan columns☆ / 药物分析学报

It is a challenge to separate the enantiomers of native chiral amines prone to deleterious silanol interactions. A set of 39 underivatized chiral primary amines was screened for enantiomeric separation. Seven recently introduced commercial chiral columns were tested. They included six polysaccharide based chiral stationary phases (CSP) with bonded derivatives, ChiralPak? IA, IB, IC, ID, IE and IF columns and a cyclofructan derivatized CSP, Larihc? CF6-P column. Both the normal phase (NP) mode with heptane/alcohol mobile phases and the polar organic (PO) mode with acetonitrile/alcohol were evaluated. It was found that the cyclofructan based CSP demonstrated the highest success rate in separating primary amines in the PO mode with only one chiral amine not resolved. It is shown that, when screening the columns, there is no standard optimal condition;an excellent mobile phase composition for one column may be poorly suited to another one. Although butylamine was a good mobile phase additive for the polysaccharide columns in both PO and NP modes, it was detrimental to the enantio-recognition capability of the cyclofructan column. Triethylamine was the appropriate silanol screening agent for this latter column.

Enantiomeric separation of zolmitriptan by CE with a sulfated β-cyclodextrin chiral selector / 中国药科大学学报

Aim:To develop a practical chiral CE method for the quantitative determination of the unwanted enantiomer[( R )-enantiomer]presented in zolmitriptan. Methods:The background electrolyte was 20 mmol/L sodium dihydrogenphosphate solution with 1% S-β-CD,adjusted to pH 3.50 with phosphoric acid. A fused-silica capillary(60 cm×50 μm ID,effective length 51.5 cm)was used at 20 ℃ for the separation. The applied voltage was -30 kV. The samples were loaded by hydrodynamic injection(50 mbar pressure,6 s). UV was measured at 220 nm. Results:Zolmitriptan and its chiral impurity were baseline resolved ( R s=6.66). The linearity was good over the concentration range from 4 to 80 μg/mL( r =0.999 8) of ( R )-enantiomer. The injection precision (expressed as CV%) was 2.83%. The average recovery was 99.97%( n =9). The limit of detection was 1.5 μg/mL. The host-guest complex binding constants were 964 and 905 mol-1 for ( R )-enantiomer and zolmitriptan,respectively. Conclusion:The method is suitable for the determination of ( R )-enantiomer in zolmitriptan and binding constants of zolmitriptan enantiomers to S-β-CD.

Determination of the Enantiomers of Ceftriaxone Sodium by Capillary Electrophoresis / 中国药房

OBJECTIVE:To develop a capillary electrophoresis method for determing the enantiomer of ceftriaxone Na.METHODS:A chiral resolving agent,?-cyclodextrin,was employed as chiral additive for ceftriaxone Na enantiomeric separation by capillary electrophoresis.In different electrophoresis polarity mode,the effect of pH of background electrolyte and the concentration of ?-cyclodextrin were investigated.RESULTS:The optimal conditions for enantiomeric separation were as follows:separation voltage:28kV,buffer solution:NaH2 PO4 50mmol/L,?-CD 0.04mmol/L,Tirs 3.0mmol/L,pH7.15.CONC_LUSION:The method is simple,sensitive,rapid and accurate,and can be used for the quality control of ceftriaxone Na enantiomers.There was significant difference in contents of enantiomers of ceftriaxone Na between products of two factories.We suggest that a quality control method for ceftriaxone Na enantiomer should be established,which will provide scientific basis for quality control of drug and clinical choice of effective antibioties.

The separation of ?-adrenoceptor antagonist enantiomers on Chiralcel~ OD column / 西安交通大学学报(医学版)

Objective To study the enantioselective characteristics and laws of ?-adrenoceptor antagonist isomers on Chiralcel ○R OD column. Methods The experiments were performed under the following HPLC conditions: a Chiralcel OD column (250 mm?4.6 mm, 10 ?m) as analytical column, a mixture of n-hexane/2-propanol/ triethylamine as the mobile phase, the fluorescence detection wavelengths at 275 nm (? ex) and 310 nm (? em), and the flow rate at 0.5 mL?min -1. The effect of interaction between stationary phase and 2-propanol or triethylamine concentration in mobile phase on the enantiomer resolution were investigated by the stoichiometric displacement model for retention. Results The lgI values of R-enantiomers of 3 out of 5 ?-adrenoceptor antagonist were higher than those of S-enantiomers. The 2-propanol in mobile phase would differently affect the resolution between enantiomers for each ?-adrenoceptor. With the increase of triethylamine concentration in mobile phase, the capacity factor (k′) of the enantiomers decreased but the resolution increased. Conclusion The lgI and Z values of SDM-R could be employed to characterize the resolution efficiency of Chiralcel OD column and the specific effect of enantiomers interacted with the stationary phase. Adding triethylamine in mobile phase will increase the resolution efficacy and changing column temperature can promote enantiomer resolution.