www.ujpsr.com 12 Vol.2, Issue 2
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756
Abstract
In the present study two rapid, inexpensive and direct chiral chromatographic methods were developed and validated for enantioseparation of racemic citalopram hydrobromide and ibuprofen and determination of their eutomers; escitalopram oxalate and dexibuprofen. The first method was based on ligand exchange reversed phase HPLC for enantioseparation of citalopram enantiomers, using 50 mM CuSO and 100 4
mM L-histidine in water/methanol on C column. The second method was 18
based on the use of mucopolysaccharide (pentosane polysulphate) as chiral selector for stereoselective separation of ibuprofen enantiomers on cyano column. The stereochemical separation factor (Ü) and the stereo chemical resolution factor (R ) obtained were 1.52 and 3.67 for citalopram s
hydrobromide and 1.97 and 6.96 for ibuprofen, respectively. Calibration curves were linear in the range of 0.4 – 2.4 µg/mL and 1.0– 80.0 µg/mL for escitalopram oxalate and dexibuprofen, respectively. The methods are specific and sensitive with lower limits of detection and quantifications of 0.109, 0.359 and 0.211, 0.696 for escitalopram oxalate and dexibuprofen, respectively.
Key words
Chiral mobile phase additives, Dexibuprofen, Escitalopram oxalate, Copper ligand, Pentosane polysulphate.
INTRODUCTION
DOI: 10.21276/UJPSR.2016.02.02.22
DIRECT STEREOCHEMICAL RESOLUTION AND ENANTIOSELECTIVE DETERMINATION OF CITALOPRAM
HYDROBROMIDE AND IBUPROFEN ENANTIOMERS BY LIGAND EXCHANGE AND MUCOPOLYSACCHARIDE AS
CHIRAL SELECTORS ON REVERSE PHASE LIQUID CHROMATOGRAPHY
1 2 1 2 Nahla N. Salama, Hala E. Zaazaa, Lobna M. Abd El Halim*, Maissa Y. Salem,Laila3E. Abd El Fattah
1Pharmaceutical Chemistry Department, National Organization for Drug Control and Research [NODCAR], 6 Abu Hazem Street, Pyramids Ave, P.O. Box 29, Giza, EGYPT
2 Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Ü Aini Street, Cairo 11562, EGYPT
3Analytical Chemistry Department, Faculty of Pharmacy, Misr University for Science & Technology, Al-
ARTICLE INFO: Article history: Received:22 August 2016Received in revised form:26 September 2016Accepted: 01 October 2016Available online: 10 November 2016
Corresponding Author: Lobna M. Abd El Halim
Quality Control Specialist
National Organization for Drug Control and Research [NODCAR], Giza, Egypt, Raw Materials Department 6 Abou Hazem Street, Pyramids Ave, P.O. Box 29, Cairo, EGYPT.
Email:
Phone: + 202-35851299
In the chiral separation by HPLC technique, the resolution between isomers is only possible by the transient formation of a pair of diastereomers with different free energy, chemical properties and consequent ly d i fferent re tent iv i t ies . These diastereomeric complexes are formed by different chiral separation mechanisms. Based on this fact, two chiral
switching drugs; citalopram hydrobromide and ibuprofen are taken as examples of enantiomar separation using different mechanisms that are applied using ligand exchange reagent and mucopolysaccharide as chiral mobile phase additives for citalopram hydrobromide and ibuprofen, respectively [1,2].
Citalopram hydrobromide (CIT): (RS)-1-(3-
www.ujpsr.com 13 Vol.2, Issue 2
dimethylaminopropyl)-1-(4-fluorophenyl)-1, 3-dihydro iso benzo furan-5-carbonitrile, HBr is selective serotonin reuptake inhibitors (SSRI) used for the treatment of various affective disorders [3]. Pharmacological effect is mainly due to the S-(+) enantiomer while R-(-) enantiomer is considered to be inactive [4]. Different techniques have been reported for separation of c i ta lopram enant iomer such as th in layer chromatography [5-7] high performance liquid chromatography [8-10] and capillary electrophoretic methods [11,12]. Ibuprofen(IBU): (RS)-2-(4-(2-methylpropyl) phenyl) propanoic acid is a non-steroidal anti-inflammatory drug (NSAID) widely used for the treatment of pain and inflammation in rheumatic disease
and other musculoskeletal disorders and is marketed as a racemate [3]. The anti-inflammatory action is mainly associated with the (+)-(S)-enantiomer [3]. Different techniques have been reported for separation of rac-ibuprofen, including high performance liquid chromatography [13-26], Capillary electrophoresis (CE) using variety of chiral selectors [27-35] and thin layer chromatography [36]. In the literature, there is no reference for direct HPLC methods using copper (II)-histidine reagent or pentosan polysulfate sodium (PPSS) as a chiral selector on C and cyano column for chiral 18
separation of racemic mixtures of CIT and IBU enantiomers. Therefore these mechanisms were chosen for rapid chiral separation of the studied drugs.
EXPERIMENTAL
APPARATUS
Analytical chromatography was performed on a HPLC system, Agilent technologies 1200 series, Germany, consisting of Agilent 1200 series variable wavelength detector G1314B/G13145 (SL), Agilent 1200 series vacuum degasser (20 µL), Agilent 1200 series manual injector and Agilent 1200 series quaternary pump G1310 A, G1311 A. Agilent Syringe, LC 50 µL, (USA) was used
for injection. Luna C column, 250 mm × 4.6 mm, 10 mm 18
(Phenomenex, USA) was used for separation of citaloptam hydrobromide enantiomers. Cyano Zorbax column, 250 mm × 4.6 mm, 5 µm (Agilent, USA) was used for separation of ibuprofen enantiomers. Cellulose acetate filter papers dimension 47 mm, pore size 0.45 µm, (ChromTech, USA) was used for filtration.
SAMPLES
PURE SAMPLES
Citalopram hydrobromide was supplied from Multi Apex Pharma (Cairo, Egypt) and its purity was found be 99.54 ± 0.824 [37]. Escitalopram oxalate oxalate was supplied from Hikma Pharma (Gizah, Egypt) and its purity was labeled to be 100.38± 0.148. L-Histidine (Otsuka Pharmaceutical, Japan) was used as chiral selector.
Ibuprofen and dexibuprofen were supplied from Sigma Pharmaceutical Industries (Cairo, Egypt) and their purities ± RSD were labeled to be 99.49 ±1.08 and 99.12 ± 0.749 respectively. Pentosane polysulphate ester sodium (Sanofi Aventis, Egypt) was used as chiral selector.
MARKET SAMPLES
Depram ® tablet was labeled to contain 20 mg citalopram / tablet, manufactured by Multi Apex Pharma (Cairo, Egypt). Estican ® tablet was labeled to contain 20 mg escitalopram oxalate/ tablet, manufactured by Hikma Pharma (Giza, Egypt). Brufen®, effervescent granules was labeled to contain 600 mg ibuprofen/sachet,
CHEMICALS AND REAGENTS
All solvents used were of HPLC grade and chemicals were of analytical grade. Potassium dihydrogen orthophosphate (Qualikems, India), Copper sulphate (Adwic Co., Egypt), acetonitrile (Poch S. A., Poland), methanol (Scarlau, Spain), isopropanol, triethylamine (Sigma Aldrich, Germany), ethanol, ethyl acetate
manufactured by El Kahira Pharmaceuticals And Chemical Industries Company (Cairo, Egypt). Flamotal ® topical gel was labeled to contain 5 g Ibuprofen /100 g cream manufactured by Global Napi Pharmaceuticals (GNP, Cairo, Egypt).
(Fischer Scientific, UK), trifluroacetic acid (Acros Organics, USA), tetrahydrofuran (Sigma Aldrich, Germany), ortho-phosphoric acid (Lab. Scan, Ireland). Water for HPLC was prepared by double glass distillation and filtration through 0.45 µm membrane filter.
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22
www.ujpsr.com 14 Vol.2, Issue 2
STANDARD STOCK SOLUTIONS
Rac-citalopram hydrobromide, escitalopram oxalate (0.1 mg/mL) and rac-ibuprofen, dexibuprofen (1 mg/mL),
WORKING STANDARD SOLUTIONS
Working standard solutions were prepared in concentration ranges of, 0.8 - 4.8 µg/mL and 0.4 - 2.4 µg/mL of rac-citalopram hydrobromide and its pure isomer escitalopram oxalate and from 2.0 - 160.0 µg/mL
CHROMATOGRAPHIC CONDITIONS
HPLC was carried out at 10 °C on Luna C column (250 18
mm × 4.6 mm, 10 µm) and mobile phase consisted of 50 mM CuSO and 100 mM L-histidine in 50 mM 4
potassium phosphate buffer (pH 5) adjusted with o-phosphoric acid: methanol: acetonitrile: tetrahydrofuran (70: 20: 10: 0.6, v/v) for CIT. While for IBU, the mobile phase consisted of 100 mg of PPSS dissolved in 75 mL of methanol to which was added 25 mL of ethyl acetate and
APPLICATION TO PHARMACEUTICAL DOSAGE FORMS
Ten tablets of Depram and Estican were weighed and ground to a fine powder. An equivalent weight corresponding to 10 mg of each was extracted with 10 mL methanol by sonication for 15 min. and filtered. The residue was washed several times with small volume of methanol. The combined extract was quantitatively transferred to 100-mL calibrated volumetric flask and evaporated. The volume was completed to the mark with mobile phase. The content of ten sachets Brufen effervescent granules was weighted and finely
RESULTS AND DISCUSSIONMobile phase additives are widely used in HPLC to regulate analyte retention behavior. The commercially available chiral stationary phases (CSP) for HPLC are very useful but extremely expensive, with short lifetimes and limited ranges 1. The basic principle of ligand exchange 2 is the involvement of L-histidine, water and
+2bivalence copper (Cu ), into CIT isomers to be resolved, through the formation of diastereomeric ternary complexes; selector/metal ion/analyte. Since the analytes and the selectors used in chiral LEC incorporate strongly polar functional groups, they are usually better dissolved in water, alcohols, or other strongly polar solvents. Any difference in stability or energy of these diasteromeric complexes results in different chromatographic
were prepared in methanol.
rac-ibuprofen and 1.0 - 80.0 µg/mL of its pure isomer dexibuprofen by appropriate dilution of standard solutions with mobile phase.
0.10 mL of TFA (concentrated), pH 3, and separation was carried out on Cyano column (250 mm × 4.6 mm, 5µm). The mobile phases were filtered using 0.45 µm membrane filter followed by degassing with ultrasonic vibration and delivered at 1 mL/min for CIT and 2.5 mL/min for IBU. The injection volume was 20 µL. Detection was achieved with UV detector at 254 nm for both drugs.
powdered. A portion equivalent to 500 mg ibuprofen was accurately transferred to 25 mL volumetric flask and extracted with about 20 mL (18: 2 methanol and water) and sonicated for 20 minutes. Then the extract was diluted to 25 mL with methanol and filtered. An accurately weighted amount of Flamotal 5% topical gel corresponding to 500 mg ibuprofen was dissolved in 20 mL methanol and transferred to 25-mL volumetric flask, sonicated for 15 minutes and diluted to the mark with methanol.
behaviors and enantiomers can be separated. The enantiorecognition of IBU isomers requires the knowledge of chiral resolution mechanism of mucopolysaccharide as chiral selector. The chiral recognition mechanism is achieved through the different hydrogen, ð-ð, and dipole-induced dipole interactions between the chiral selector, stationary phase and the enantiomers [36]. It has been observed that PPSS has greater resolution capacity than most known mucopolysaccharide attributed to the fact that the PPSS are more helical in nature and possess well-defined grooves. The schematic enantioseparation mechanism of CIT and IBU was illustrated in Figure (1) and (2).
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22
www.ujpsr.com 15 Vol.2, Issue 2
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22
Fig. 1: Schematic enantioseparation mechanism of the ternary complex formation of citalopram and L-histidine amino acid with Cu (II).
Fig.2: Schematic enantioseparation mechanism of the complex formed between pentosane polysaccharide and ibuprofen.
The optimized mobile phase for enantioseparation of CIT was 50 mM CuSO and 100 mM L-histidine in 50 4
mM potassium phosphate buffer (pH 5): methanol : acetonitrile: THF (70: 20: 10: 0.6, v/v) and detection at 254 nm. The order of elution was R (-) enantiomer then S (+) enantiomer with retention times of 2.18 and 2.99 respectively (Figure 3). The optimized mobile phase of
IBU racemic mixture was 100 mg of PPSS dissolved in 75 mL of methanol to which was added 25 mL of ethyl acetate and 0.10 mL of TFA (concentrated), pH 3 and detection at 254 nm. The order of elution was R (-) enantiomer then S (+) enantiomer and their retention times were 1.16 and 1.71 in drug substance and drug product respectively (Figure 4).
www.ujpsr.com 16 Vol.2, Issue 2
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22METHOD VALIDATION [38]
The validation parameters of the optimized methods were given in Table (1). Good linearity was observed for the active isomers of the studied drugs over the concentration range of 0.4 - 2.4 µg/mL with a linear regression equation, y = 1623.2x + 72.33 (r = 0.9995, n = 6) for CIT and 1 - 80 µg/mL with a linear regression equation, y = 25.64 x + 61.71 (r = 0.9995, n = 6) for IBU. The LOD and LOQ were calculated and found to be 0.109, 0.359 for CIT and 0.211, 0.696 for IBU respectively. The results of method precisions are expressed in terms of RSD% values for retention times and peak areas for the active isomers are presented in Table (1). The RSD% for repeatability (within-day precision, n=3) and RSD for reproducibility
Fig. 3: A typical HPLC chromatogram of (A) 0.8 µg /ml racemic CIT in drug substance, (B) 0.8 µg /ml pure escitalopram (C) 4.8 µg /ml racemic CIT in Depram ®tablet, (D) sequential concentration of racemic citalopram (0.8 - 4.8 µg /ml) at conditions of a Luna C column (250 mm × 4.6 mm, i.d., 10 ìm) eluting 18
with the mobile phase of 50 mM CuSO and 100mM L-histidine in 50 mM potassium phosphate buffer 4
(pH 5) adjusted with o-phosphoric acid : methanol: acetonitrile: THF (70:20:10:0.6) and detection at 254 nm
(between-day precision, n=3) for each enantiomer at three different quantification concentrations were found to be less than 2%. These results confirmed the good precision of the methodGood recoveries were obtained for the active and racemic forms in drug substances and pharmaceutical dosage forms as represented in Tables (2) and (3). Robustness of the methods was assessed by evaluating the influence of small change of experimental conditions, such as organic strength, pH and flow rate, and the system suitability parameters were evaluated as represented in Table (4) and (5). The methods showed acceptable robustness as deliberated changes of any variable Therefore, the methods are robust and reliable.
17 Vol.2, Issue 1
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22
Fig. 4: A typical HPLC chromatogram of (A) racemic IBU in drug substance, (B) pure dexibuprofen, (C) and (D) ) racemic IBU in Brufen effervescent granules and Flamotal topical gel, (E) sequential
concentration of ibuprofen (1 - 40 µg /ml) at conditions of Cyano Zorbax column, 250 mm × 4.6 mm, 5 ìm; Mobile phase, 100 mg pentosane polysulphate sodium in methanol: ethyl acetate: TFA (75:25:0.1), pH 3;
flow-rate, 2.5 mL /min; detection wavelength, 254 nm.
Table 1: Validation and regression equations parameters for the proposed chiral HPLC methods for the determination of escitalopram and dexibuprofen in drug substances
www.ujpsr.com
Parameters Escitalopram Dexibuprofen
Linearity range 0.4 – 2.4 1.0 – 80.0
LOD (µg/mL)LOQ (µg/mL)
0.1090.359
0.2110.696
AccuracyaMean ± RSD% bMean ± RSD% cMean ± RSD%
97.82 ± 0.795
48.80 ± 1.450
101.52 ± 0.63954.44 ± 0.63056.10 ± 2.13656.40 ± 2.153
Precision Instrumental repeatability t r
Peak areasMethod repeatability t r
Peak areasInterday precision t rPeak areas
0.1630.4810.2200.3820.2620.585
0.6930.7000.6770.7620.6250.629
25.6480.389
24.56-26.7261.7117.47
13.18 -110.240.999526.62
1623.21425.617
1552.09-1694.3372.3339.905
-38.64 -183.120.999542.865
Regression equation-SlopeSE of the slope
eCL of the slope -InterceptSE of the intercept
eCL of the intercept-Correlation coefficient-SE of estimation
a. Drug substance (pure isomer). b. Drug substance (racemic form).c. Pharmaceutical formulation (racemic form).d. Pharmaceutical formulation (racemic form). e. 95 % Confidence limit.
www.ujpsr.com 18 Vol.2, Issue 1
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22Table (2a): Accuracy of the proposed LEC HPLC method for the determination of escitalopram
oxalate in drug substance as pure isomer and in rac-citalopram
0.37
0.79
1.57
1.99
2.38
0.8
1.6
3.2
4
4.8
Escitalopram (pure isomer) Citalopram (Racemic mixture)
Taken conc.
(µg/mL)
Taken conc.
(µg/mL)
Found conc.
(µg/mL)
Found conc.
(µg/mL)
Recovery * (%) RSD% RSD%
Recovery * (%) of claimed amount
0.4
0.8
1.6
2
2.4
Mean RSD% 97.82 0.795 Mean RSD% 49.22 1.002
0.39
0.78
1.55
1.97
2.37
97.50
97.50
96.87
98.50
98.75
0.265
0.514
0.609
0.381
0.649
0.258
0.214
0.362
0.325
0.228
47.50
49.93
49.37
49.50
49.79
*Average of four different determinations
Table (2b): Accuracy of the proposed LEC HPLC method for the determination of escitalopram oxalate in drug products as pure isomer and in rac-citalopram
Taken conc.
(µg/mL)
Taken conc.
(µg/mL)
Found conc.
(µg/mL)
Found conc.
(µg/mL)
Recovery * (%) RSD% RSD%
Recovery * (%) of claimed amount
Mean RSD% Mean RSD%
Estikan tablet (20 mg Escitalopram/ tablet) ( Depram tablet) (20 mg Citalopram/ tablet)
2.4
0.4
0.8
1.6
2
0.4080.39 97.00 0.125 0.37 46.250.8
2.37
0.78
1.55
1.97
0.34997.25 0.243 1.6 0.79 49.37
97.91
96.25
97.50
0.2610.208 3.2 1.57 49.06
0.199
0.234 0.7614 1.99 49.75
0.9324.8 2.38 49.58
97.18 0.639 48.80 1.450
*Average of four different determinations
Table (3a): Accuracy of the proposed HPLC method for the determination of dexibuprofen in drug substance as pure isomer and in rac-ibuprofen
Ibuprofen (Racemic mixture)
Taken conc.
(µg/mL)
Taken conc.
(µg/mL)
Found conc.
(µg/mL)
Found conc.
(µg/mL)
Recovery * (%) RSD% RSD%
Recovery * (%) of claimed amount
Mean RSD% Mean RSD%
Dexibuprofen (Pure isomer)
80.0
1.0
10.0
20.0
40.0
0.1581.02 102.00 0.325 1.03 51.502.0
80.85
10.12
20.19
40.97
0.392101.20 0.492 20.0 10.25 51.25
101.06
100.95
102.42
0.4220.931 40.0 20.41 51.02
0.723
0.581 0.52580.0 41.91 52.38
0.528160.0 82.36 51.47
101.52 0.639 54.44 0.630
*Average of four different determinations.
ParametersSelectivity, á (NLT 1.0)
Resolution, Rs(NLT 1.5)
Tailing factor, T (NMT 3)
Column efficiency, N(NLT 1000)
RSD % of six replicate
injections
Flow rate0.9 ml/min1.1 ml/min
Buffer pH4.85.2
Column temperature8°C12°C
Organic modifier bvolume
19ml21ml
Organic modifier cvolume
9.8 ml10.2 ml
Organic modifier dvolume
0.58 ml0.62 ml
1.511.50
3.673.65
1.221.21
19011989
0.2300.154
1.501.50
3.663.67
1.211.20
21611921
0.2410.321
1.511.50
3.673.65
1.201.23
21482006
21482006
1.511.51
3.643.67
1.221.23
20272135
0.2850.225
1.501.50
3.643.65
1.211.24
21842972
21842972
1.511.50
3.673.65
1.201.22
21471938
0.1460.325
Flamotal topical gel(5 g Ibuprofen/100 g cream)
Taken conc.
(µg/mL)
Taken conc.
(µg/mL)
Found conc.
(µg/mL)
Found conc.
(µg/mL)
Recovery * (%) RSD% RSD%
Recovery * (%) of claimed amount
MeanRSD%
MeanRSD%
Brufen effervescent granules(600 mg ibuprofen/sachet)
160.0
2.0
20.0
40.0
80.0
0.6321.16 58.00 0.205 1.16 58.002.0
88.21
11.21
22.52
44.02
0.54256.05 0.425 20.0 11.23 56.15
55.13
56.30
55.02
0.4090.647 40.0 22.92 57.30
0.825
0.741 0.48780.0 44.15 55.18
0.321160.0 88.64 55.40
56.102.136
56.402.153
www.ujpsr.com 19 Vol.2, Issue 2
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22
Table (3b): Accuracy of the proposed HPLC method for the determination of dexibuprofen in rac-ibuprofen drug product
*Average of four different determinations.
aTable 4: Summary of robustness data and system suitability parameters for separation of citalopram hydrobromide enantiomers
a. Values in parentheses are the system suitability acceptance criteria. NMT= not more than; NLT = not less than; á= selectivity; Rs = resolution between the adjacent peaks.b. Methanolc. Acetonotriled. Tetrahydrofuran
www.ujpsr.com 20 Vol.2, Issue 2
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22aTable 5: Summary of robustness data and system suitability parameters for separation of ibuprofen
enantiomers
Selectivity, á (NLT 1.0)
6.966.92
1.161.16
80848089
0.2140.321
1.971.97
6.956.96
1.171.15
80788093
0.3050.411
Column temperature14.8 °C15.2 °C
1.951.97
6.966.94
1.171.18
80718079
0.2790.321
1.961.97
6.926.95
1.191.17
80868075
0.3090.401
Organic modifier cvolume
24 ml26 ml
1.971.95
6.966.95
1.161.18
82658055
0.4960.436
ParametersResolution, Rs
(NLT 1.5)Tailing factor,
T (NMT 3)
Column efficiency, N(NLT 1000)
RSD % of six replicate
injections
Flow rate2.4 ml/min2.6 ml/min
Buffer pH2.83.2
1.971.96
Organic modifier bvolume
74ml76ml
a Values in parentheses are the system suitability acceptance criteria. NMT= not more than; NLT = not less than; á= selectivity; Rs = resolution between the adjacent peaks. b Methanol.C Ethyl acetate
CONCLUSION
The paper describes improved, simple and inexpensive methods to analyze enantiomeric mixtures of citalopram hydrobromide and ibuprofen, suitable to be used routinely by any group working in quality control laboratories as well as to describe the importance of the chiral selector structure to the desired enantioseparations and its implications on the chromatographic parameters. The proposed methods are clearly superior to published methods being application inexpensive. The stereospecificity was achieved by CLEC and
mucopolysaccharide chiral selectors on conventional columns. The optimum HPLC methods were found to be sensitive and selective for identification and quantitative determination of enantiomeric purity of escitalopram oxalate and dexibuprofen in their drug substances and products. The methods can be useful to investigate adultration of pure isomers with cheap racemic forms. The proposed methods are clearly superior to published methods
REFERENCES
1. Aboul-Enein, HY, lmran, A. Chiral separation by liquid chromatography and related technologies USA: Marcel Dekker INC.; 2003.
2. Gübitz G, Schmid MG. Chiral Separations Methods and Protocols. New Jersey: Humana Press Inc.; 2004.
www.ujpsr.com 21 Vol.2, Issue 2
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.223. Sweetman SC. Martindale: The complete drug
r e f e r e n c e . 3 5 t h e d . L o n d o n : T h e pharmaceutical press; 2007.
4. Hyttel J, Larsen JJ. Selective serotonin antidepressants. Acta Pharmacol Toxicol. 1985; 56: 146-153.
5. Mahadik MV, Dhaneshwar SR, Kulkarni MJ. Application of stability indicating HPTLC method for quantitative determination of e s c i t a l o p r a m o x a l a t e o x a l a t e i n pharmaceutical dosage form. Euras J Anal Chem. 2007; 2 (2): 101-117.
6. Taha AE, Salama NN, Shudong W. Micelle enhanced fluorimetric and thin layer chromatography densitometric methods for the determination of (±) citalopram and i t s S -enant iomer esc i ta lopram oxalate. Anal Chem Ins. 2009; 4: 1-9.
7. Suzan MS. Validated densitometric TLC-method for the simultaneous analysis of ®- and ( S ) - c i t a l o p r a m a n d i t s r e l a t e d substances using macrocyclic antibiotic a s a chiral selector: A p p l i c a t i o n t o t h e determination of enantiomeric p u r i t y o f escitalopram oxalate. Int J Biomed S c i 2012; 8(1): 40-50.
8. Haupt, D. Determination of citalopram enant iomers l iqu id chromatographic separation in human plasma by Chiral-AGP. J Chromatogr B. 1996; 685: 299-305.
9. Nageswara RR, Narasa RA, Nagaraju D. Development and validation of a liquid chromatographic method for determination of enantiomeric purity of citalopram in bulk drugs and pharmaceuticals. J Pharm Biomed Anal; 2006; 41: 280-285.
10. El-Gindy A, Emara S, Mesbah M, Hadad G. Liquid Chromatography Determination of Citalopram Enantiomers Using -Cyclodextrin as a Chiral Mobile Phase Additive. J AOAC International. 2006; 89(1): 65-70.
11. Juan JBN, Carmen GC, Maria JVL. Enantiomeric determination, validation and robustness studies of racemic citalopram in pharmaceutical formulations by capillary electrophoresis. J Chromatogr A. 2005; 1072: 249-257.
12. Bunleu S, Pavel J, Gerhard KE, Scriba A.
Enantiomeric separation of citalopram and its metabolites by capillary electrophoresis. Electrophoresis. 2008; 46: 959-965.
13. Naidong W, Lee JW. Development and validation of a liquid chromatographic method for the quantitation of ibuprofen enantiomers in human plasma. J Pharm Biomed Anal. 1994; 12(4): 551-556.
14. Vermeulen B, Remon JP, Validation of a high-performance liquid chromatographic method for the determination of ibuprofen enantiomers in plasma of broiler chickens. J Chromatogr B. 2000; 749(2): 243-251.
15. Teng XW, Wang SWG, Dav ie s NM. Stereospecific high-performance liquid chromatographic analysis of ibuprofen in rat serum. J Chromatogr B. 2003; 796(2): 225-231.
16. Oliveira ARM, Cesarino EG, Bonato PS. Solid-phase microextraction and chiral HPLC analysis of ibuprofen in urine. J Chromatogr B;2005: 818(2), 285-291.
17. Bonato PS, M Del Lama M PF, de Carvalho R. Enantioselective determination of ibuprofen in p lasma by h igh -per formance l i qu id c h ro m a t o g r a p h y - e l e c t ro s p r a y m a s s spectrometry. J Chromatogr B. 2003; 796(2): 413-420.
18. Ahn HY, Shiu GK, Trafton WF, Doyle TD. R e s o l u t i o n o f t h e e n a n t i o m e r s o f ibuprofen;comparison study of diastereomeric method and chiral stationary phase method. J Chromatogr B. 1994: 653(2); 163-169.
19. McDaniel DM Snider BG. Resolution of ?-arylacetic acid enantiomers on two chiral stationary phases. J. Chromatogr. A. 1987; 404: 123-132.
20. Avgerinos A, Hutt AG. Determination of the enantiomeric composition of ibuprofen in human plasma by high-performance liquid chromatography. J Chromatogr B. 1987; 415: 75-83.
21. P e t t e r s s o n K J , O l s s o n A . L i q u i d chromatographic determination of the enantiomers of ibuprofen in plasma using a chiral AGP column. J Chromatogr B. 1991; 563(2): 414-418,
22. Wright MR, Sattari S, Brocks DR , Jamali F.
www.ujpsr.com 22 Vol.2, Issue 2
I m p ro v e d h i g h - p e r f o r m a n c e l i q u i d chromatographic assay method for the enantiomers of ibuprofen. J Chromatogr B. 1992; 583(2): 259-265.
23. Geisslinger G, Dietzel K, Loew D,Schuster O, Rau G, Lachmann G,Brune K, High-per formance l iquid chromatographic determination of ibuprofen, its metabolites and enantiomers in biological fluids. J Chromatogr B. 1989; 491: 139-149.
24. S. Menzel-Soglowek, G. Geisslinger and K. Brune, Stereoselective high-performance liquid chromatographic determination of ketoprofen, ibuprofen and fenoprofen in plasma using a chiral ?1-acid glycoprotein column. J Chromatogr B. 1990; 532: 295-303.
25. Lemko CH, Caillé G, Foster RT, Stereospecific high-performance liquid chromatographic assay of ibuprofen: improved sensitivity and sample processing efficiency. J Chromatogr B. 1993; 619(2): 330-335.
26. Toyo'oka T, Ishibashi M , Terao T. Further studies on the resolution of carboxylic acid enantiomers by liquid chromatography with fluorescence and laser-induced fluorescence detection. Anal. Chim. Acta. 1993; 278(1): 71-81.
27. Simó C, Gallardo A,San Román J, Barbas C , Cifuentes A. Fast and sensitive capillary electrophoresis method to quantitatively monitor ibuprofen enantiomers released from polymeric drug delivery systems. J Chromatogr B. 2002; 767(1): 35-43.
28. Reijenga JC, Ingelse BA Everaerts FM. Thermodynamics of chiral selectivity in capillary electrophoresis: separation of ibuprofen enantiomers with ?-cyclodextrin. J Chromatogr A. 1997; 792(1-2), 371-378.
29. G?ówka FK, Kara?n iewic M. H igh performance capillary electrophoresis method for determination of ibuprofen enantiomers in human serum and urine. Anal. Chim. Acta. 2005; 540(1): 95-102.
30. Tian Y, Zhong C, Fu E, Zeng Z. Novel ?-cyclodextrin derivative functionalized polymethacrylate-based monolithic columns for enantioselective separation of ibuprofen and naproxen enantiomers in capillary
RESEARCH ARTICLEDepartment of Pharmaceutical Chemistry
Lobna et.al / UJPSR / 2 (2), 2016, 12-22 e ISSN: 2454-3764
Print ISSN: 2454-3756DOI: 10.21276/UJPSR.2016.02.02.22electrochromatography. J Chromatogr A. 2009, 1216(6), 1000-1007.
31. Vincent JB, Vigh G. Nonaqueous capillary electrophoretic separation of enantiomers using the single-isomer heptakis (2, 3-diacetyl-6-sulfato)-?-cyclodextrin as chiral resolving agent. J Chromatogr A. 1998; 816(2): 233-241.
32. Blanco M, Coello J, Iturriaga H, Maspoch S Pérez-Maseda C.,Separation of profen enantiomers by capillary electrophoresis using cyclodextrins as chiral selectors. J . Chromatogr. A. 1998; 793(1): 165-175.
33. G?ówka FK, Kara?niewicz M. High performance capillary electrophoresis for determination of the enantiomers of 2-arylpropionic acid derivatives in human serum: Pharmacokinetic studies of ketoprofen enantiomers following administration of standard and sustained release tablets. J. Pharm. Biomed. Anal. 2004; 35(4): 807-816.
34. Rawjee YY, Williams RL, Vigh G. Capillary electrophoretic chiral separations using cyclodextrin additives: III. Peak resolution surfaces for ibuprofen and homatropine as a function of the pH and the concentration of ?-cyclodextrin. J Chromatogr A. 1994; 680(2): 599-607.
35. Fanali S, Desiderio C, Schulte G, Heitmeier S, Strickmann D, Chankvetadze B, Blaschke G. Chiral capillary electrophoresis-electrospray mass spectrometry coupling using vancomycin as chiral selector. J Chromatogr A.1998; 800(1): 69-76.
36. Nishi H, Enantiomer separation of drugs by electrokinetic chromatography. J Chromatogr A. 1996: 735: 57-76.
37. Tchapla A, Heron S, Lesellier E. Enantiomer separation of drugs by electrokinetic chromatography. J Chromatogr A. 1993: 656: 81-85.
38. The British Pharmacopoeia, Volumes IV, Her Majesty's Stationery Office, London, UK 2013.
39. ICH Harmonized Tripartite Guideline, Validation of Analytical Procedures, Text and Methodology, Q2 (R1), International Conference on Harmonization, IFPMA, Geneva, 2005.