RP-HPLC Determination of Famotidine and its Potential Impurities in Pharmaceuticals

A simple, sensitive, and rapid reversed-phase high-performance liquid chromatographic method has been developed for determination of famotidine (FMT) and its impurities in pharmaceutical formulations. Separations were performed on a Supelcosil LC18 column with an isocratic mobile phase—13:87 (v/v) acetonitrile–0.1 M dihydrogen phosphate buffer containing 0.2% triethylamine (pH 3.0). The mobile phase flow rate was 1 mL min^–1 and the detection wavelength was 265 nm. Response was linearly dependent on concentration between 1 and 80 g mL^–1 (regression coefficient, R², from 0.9981 to 0.9999). RSD from determination of method repeatability (intraday) and reproducibility (interday) were <2% (n=6). Lowest detectable concentrations ranged from 0.08 to 0.14 g mL^–1. The proposed liquid chromatographic method can be satisfactorily used for routine quality control of famotidine in pharmaceutical formulations.     

Determination of Nisoldipine and Its Impurities in Pharmaceuticals

A method has been established for separation of nisoldipine and impurities, for example reactants, products of side-reactions, and photodegradation products, by HPTLC on LiChrospher Si 60 F_254s plates with detection at 280 nm. The mobile phase, cyclohexane–ethyl acetate–toluene, 7.5:7.5:10 (v/v), enables acceptable resolution of nisoldipine, in large excess, and possible impurities. Regression coefficients (r 0.997), recovery (98–108%), and determination limit (0.02–0.2%) were validated and found to be satisfactory. The method is convenient for quantitative analysis and purity control of nisoldipine in its raw material and dosage forms.     

LC Determination of Clonidine Hydrochloride in Chinese and Western Combine Compound Hypotensor Tablets of Zhenju Jiangya

A new method has been developed to determine clonidine hydrochloride in Zhenju Jiangya Tablets using ion-pair HPLC coupled with neutral column chromatography in this paper. Clonidine hydrochloride is an active component and occurs in very low amounts. The sample was purified by neutral Al₂O₃ column chromatography instead of liquid–liquid extraction and measured by reversed phase ion-pair chromatography with 1-heptanesulfonate at acidic pH with UV-detection. Result showed that clonidine hydrochloride had good linearity in the range of 1.1–11.0 μg mL⁻¹ (r = 0.9993) and the average recoveries were 96.5–99.3% (RSD 2.1–4.8%).     

Simultaneous Determination of Olanzapine and Fluoxetine by HPLC

A rapid, specific reversed phase HPLC method has been developed for simultaneous determination of olanzapine and fluoxetine in their formulations. Chromatographic separation of these two pharmaceuticals was carried out on an Inertsil C₁₈ reversed phase column (150 mm × 4.6 mm, 5 μm) with a 40:30:30 (v/v/v) mixture of 9.5 mM sodium dihydrogen phosphate (pH adjusted to 6.8 ± 0.1 with triethylamine), acetonitrile and methanol as mobile phase. The flow rate 1.2 mL min⁻¹ and the analytes are monitored at 225 nm. Paroxetine was used as internal standard. The assay results were linear from 25 to 75 μg mL⁻¹ for olanzapine (r ² ≥ 0.995) and 100–300 μg mL⁻¹ for fluoxetine (r ² ≥ 0.995), showed intra- and inter-day precision less than 1.0%, and accuracy of 97.7–99.1% and 97.9–99.0%. LOQ was 0.005 and 0.001 μg mL⁻¹ for olanzapine and fluoxetine, respectively. Separation was complete in less than 10 min. Validation of the method showed it to be robust, precise, accurate and linear over the range of analysis.     

Simultaneous Determination of Metformin Hydrochloride, Cyanoguanidine and Melamine in Tablets by Mixed-Mode HILIC

A simple and specific hydrophilic interaction liquid chromatography (HILIC) procedure for the quantification of metformin hydrochloride (MFH) and its impurities in bulk pharmaceuticals and finished dosage forms has been developed. The method is based on hydrophilic interaction of the analytes with silica. The influence of the weaker solvent, acetonitrile, pH and the nature and ionic strength of the buffer was studied. Linearity range and percent recoveries for MFH were 100–400 μg mL⁻¹ and 100.62%, respectively. Good validation data were obtained for all compounds. The method separates impurities cyanoguanidine (CGD), melamine (MLN) and other degradation products with a run time of less than 13 min. Degradation studies involved thermal stress, hydrolysis at various pHs and chemical and photolytic oxidation.     

Determination of potential degradation products of piroxicam by HPTLC densiometry and HPLC

Summary HPTLC densitometry and HPLC are considered for the simultaneous determination of the degradation products of piroxicam (2-aminopyridine, DP-I and DP-II). The substances were separated on silica gel with fluorescence indicator in ethylacetate — toluene — diethylamine (10∶10∶5) and toluene — absolute ethanol — glacial acetic acid (8∶1.2∶0.5) systems. The measuring absorbance (detection of reflectance) of the separated substances was carried out “in situ” at 296 nm using 4-level calibration (external standard, nonlinear regresson function) in the concentration range 600–1200 ng 2-aminopyridine/spot and 300–600 ng DP-I and DP-II/spot. The HPLC method was carried out using RP-8 stationary phase and methanol + phosphate-citrate buffer, pH 3 mobile phase with addition of sodium pentanesulfonate (40+60, v/v). 2-aminopyridine wass detected at 300 nm, DP-I at 280 nm and DP-II at 248 nm. The concentration range for 2-aminopyridine is 2–40 μg/ml, for DP-I and DP-II 2–20 μg/ml (for an injection volume of 10 μl). The results were evaluated by linear regression analysis.     

Determination of vitamins A, D, E, and K in human and bovine serum, and β-carotene and vitamin A palmitate in cosmetic and pharmaceutical products, by isocratic HPLC

Summary An HPLC method has been developed for the determination of fat-soluble vitamins. Ten fat-soluble vitamins were separated simultaneously on a 25 cm×4.6 mm i.d. Hypersil C₁₈ column with acetonitrile-dichloromethane-methanol, 60:20:20 (v/v) as mobile phase at 1.0 mL min⁻¹ with wavelength-programmed ultraviolet-visible-absorbance detection. Total analysis time was 12 min. The limits of detection were 0.03, 0.01, 0.55, 1.84, 0.02, 0.02, 0.01, 0.16, 0.33, 0.01, and 0.01 ng mL⁻¹ for retinol, retinyl acetate, retinyl palmitate, β-carotene, ergocalciferol, cholecalciferol, tocopherol, tocopherol acetate, phylloquinone, menatetrenone, and menadione, respectively. Analysis of human serum 2–7 days after ingestion of oral vitamins and Chinese herbs led to the conclusion that the concentration of vitamins was higher than for control serum.     

Determination of trace amounts of morpholine and its thermal degradation products in boiler water by HPLC

Summary Morpholine and its amine-type thermal degradation products present in boiler feed water and steam condensate were derivatised with N-succinimidyl-p-nitrophenylacetate. These pre-column derivatives were determined by high-performance liquid chromatography with UV detection at 280 nm. The analytical column was Supelco-sil-ODS with an isocratic mobile phase. Morpholine and its breakdown products were monitored in the range 0.01–10 g ml^–1 with a relative standard deviation of 0.4–3.0%. Chromatographic analysis of boiler feed water and steam condensate samples collected from a boiler servicing a petroleum refinery is described.     

Determination of the Enantiomers of Tamsulosin Hydrochloride and its Synthetic Intermediates by Chiral Liquid Chromatography

A chiral liquid chromatographic method is described for the determination of the enantiomers of tamsulosin hydrochloride and its synthetic intermediates. Enantioseparation was achieved on a Chiralcel OD-R column (250 mm × 4.6 mm, 10 m) using a mobile phase consisting of a mixture of 0.5 mol L^–1 sodium perchlorate and acetonitrile (80:20, v/v, pH 4.0). The flow rate was 0.4 mL min^–1 and detection was at 223 nm. Excellent enantiomer separations were achieved for tamsulosin hydrochloride and its synthetic intermediates. No other methods are available for the separation of these enantiomers. The method developed in this study has been successfully applied for purity control.     

Simultaneous Determination of Bifonazole and Benzyl Alcohol in Pharmaceutical Formulations by Reverse-Phase HPLC

A simple, precise and sensitive reverse-phase high performance liquid chromatographic (RP-HPLC) method has been developed for the quantitation of bifonazole, an imidazole antifungal, simultaneously with benzyl alcohol, used as preservative, in pharmaceutical formulations. Method employed Zorbax Eclipse XDB-C18 (250×4.6 mm i.d., 5 m) column, methanol - ammonium acetate (pH 2; 65 mM) (65:35, v/v, pH^* 3.6) as mobile phase with flow rate of 1 mL min^–1 and variable UV detection at 220 and 252 nm. The proposed method was validated by testing its linearity, selectivity, recovery, repeatability, LOD/LOQ values and it was successfully employed for the determination of bifonazole and benzyl alcohol in pharmaceutical cream-based formulations.     

HPLC with Diode-Array Detection for Determination of Leflunomide in Tablets

We have developed and validated a simple HPLC method for analysis of leflunomide in tablets. Method conditions were determined by assay of a photodegraded sample of leflunomide. Optimum chromatographic performance was obtained with a C₁₈ column and acetonitrile-water as mobile phase. Comparison of spectra recorded with a diode-array detector during elution of the leflunomide peak enabled determination of method specificity. The method is highly sensitive (detection limit 10 ng mL⁻¹) and robust to deliberate variation of the conditions (RSD of peak area < 2.0%). Precision and accuracy were adequate over the concentration range 10 to 100 μg mL⁻¹. These results show the proposed method is suitable for its intended use.     

Development and Validation of High Performance Liquid Chromatographic and UV-Derivative Spectrophotometric Methods for the Determination of Sotalol Hydrochloride in Tablets

Abstract

High performance liquid chromatographic (HPLC) and UV derivative spectrophotometric (UVDS) methods were developed and validated for the quantitative determination of sotalol hydrochloride in tablets. The HPLC method was performed on a C18 column with fluorescence detection. The excitation and emission wavelengths were 235 and 310 nm, respectively. The mobile phase was composed of acetonitrile-water containing 0.1% trietylamine (7:93 v/v) and pH adjusted to 4.6 with formic acid. The UVDS method was performed taking a signal at 239.1 nm in the first derivative. The correlation coefficients (r) obtained were 0.9998 and 0.9997 for HPLC and UVDS methods, respectively. The proposed methods are simple and adaptable to routine analysis.     

HPLC analysis of aspartame and saccharin in pharmaceutical and dietary formulations

Summary A reversed-phase HPLC method has been developed suitable for a reliable quality control of pharmaceutical and dietary formulations containing the synthetic sweeteners aspartame and saccharin. The proposed method is able to separate acesulfame, aspartame and saccharin, and their impurities such as 5-benzyl-3,6-dioxo-2-piperazineacetic acid (the major degradation product of aspartame) and 4-sulphamoylbenzoic acid,o- andp-toluenesulphonamides (the synthesis impurities of saccharin). A convenient solid-phase extraction (SPE) procedure using C-18 sorbent, was also developed for the determination of potential saccharin impurities.     

A Rapid Stability-Indicating LC Method for Ziprasidone Hydrochloride

A simple and rapid reversed-phase liquid chromatographic method was developed for the related substances determination and quantitative evaluation of ziprasidone hydrochloride, which is used as an antipsychotic agent. Forced degradation studies were performed on bulk sample of ziprasidone hydrochloride using acid, base, oxidative hydrolysis, thermal stress and photolytic degradation. Mild degradation of the drug substance was observed during thermal stress and considerable degradation observed during base hydrolysis. The chromatographic method was fine tuned using the samples generated from forced degradation studies. Good resolution between the peaks corresponds to synthetic impurities and degradation products from the analyte were achieved on YMC Pack Pro C18 column using the mobile phase consists of a mixture of 0.05% v/v of phosphoric acid in water and acetonitrile. The stressed test solutions were assayed against the qualified working standard of ziprasidone hydrochloride and the mass balance in each case was close to 99.7% indicating that the developed method was stability-indicating. Validation of the developed method was carried out as per ICH requirements.     

Development and Validation of a Micellar Liquid Chromatographic Method with UV Detection for Determination of Azithromycin in Tablets and Capsules

A rapid and simple micellar liquid chromatographic method that does not require use of specific chromatographic columns has been developed and validated for azithromycin determination. The method uses a Hypersil C₁₈ column at 60 °C, 1-butanol–pH 6.86 phosphate buffer solution–water, 15:25:60 (v/v), containing 0.10 M sodium dodecyl sulfate, as mobile phase, and UV-detection at 215 nm. Different characteristics of the method were validated satisfactorily. The specificity, accuracy, linearity, precision (repeatability), and robustness of the method were demonstrated. The method proved suitable for determination of the azithromycin content of capsules and uncoated tablets.Revised: 5 February and 11 March 2004     

Stability Indicating HPTLC and LC Determination of Dasatinib in Pharmaceutical Dosage Form

Two sensitive and reproducible methods are described for the quantitative determination of dasatinib in the presence of its degradation products. The first method was based on high performance thin layer chromatography (HPTLC) followed by densitometric measurements of their spots at 280 nm. The separation was on HPTLC aluminium sheets of silica gel 60 F₂₅₄ using toluene:chloroform (7.0:3.0, v/v). This system was found to give compact spots for dasatinib after development (R _F value of 0.23 ± 0.02). The second method was based on high performance liquid chromatography (HPLC) of the drug from its degradation products on reversed phase, PerfectSil column [C₁₈ (5 μm, 25 cm × 4.6 mm, i.d.)] at ambient temperature using mobile phase consisting of methanol:20 mM ammonium acetate with acetic acid (45:55, v/v) pH 3.0 and retention time (t _R = 8.23 ± 0.02 min). Both separation methods were validated as per the ICH guidelines. No chromatographic interference from the tablet excipients was found. Dasatinib was subjected to acid–alkali hydrolysis, oxidation, dry heat, wet heat and photo-degradation. The drug was susceptible to acid–alkali hydrolysis and oxidation. The drug was found to be stable in neutral, wet heat, dry heat and photo-degradation conditions. As the proposed analytical methods could effectively separate the drug from its degradation products, they can be employed as stability indicating.     

Determination of Tandospirone and its Impurities in Drug Formulations by LC-UV and LC-MS

This work describes the determination of tandospirone in bulk drug substance and formulated products by a reversed-phase liquid chromatographic method with UV detection. Chromatographic separation was performed on a C₁₈ column with a mobile phase of a binary mixture of methanol and water (70:30, v/v) delivered at a flow rate of 0.5 mL min^–1 and detection was performed at 243 nm. The proposed LC method is selective, precise and accurate for the determination of tandospirone in the presence of its manufacturing impurities with a limit of quantitation of 0.54 g mL^–1. A preliminary study for the identification of the major manufacturing impurities was made by liquid chromatography-mass spectrometry with electrospray ionization source operated in a positive ion mode.     

Development and validation of an improved liquid chromatographic method for the analysis of oxytetracycline

Summary An improved LC method is described for the separation of oxytetracycline and its impurities. The separation is much better than that obtained with official pharmacopoeia methods. The method uses XTerra RP-18, 5 μm (25cm×4.6 mm I.D.), a silica-based stationary phase with methyl end-capping, claimed to reduce silanol activity. The column temperature is set at 30°C and a UV detection is performed at 280 nm. Mobile phase containing acetonitrile −0.25 M tetrabutylammonium hydrogen sulfate pH 7.5−0.25 M ethylenediaminetetraacetic acid pH 7.5-water (115:360:160:365,v/v/v/v) is used at a flow rate of 1.0 mL.min⁻¹, to separate the impurities present in oxytetracycline base. A central composite experimental design is used to optimize the separation. A second isocratic method with higher content of acetonitrile is needed to separate the more retained impurities present only in oxytetracycline hydrochloride. The method is robust and shows good selectivity, repeatability, linearity and sensitivity.     

Chromatographic determination of caffeine in pharmaceutical formulations using micellar mobile phases

Summary An HPLC procedure is described for the determination of caffeine in pharmaceutical preparations. A Spherisorb octadecylsilane ODS-2 C₁₈ analytical column and spectrophotometric detection at 273 nm were used. The chromatographic behaviour of caffeine with different micellar eluents containing sodium dodecyl sulphate (SDS) is described. The determination of caffeine in pharmaceutical preparations was performed by use of a mobile phase containing 0.05 M sodium dodecylsulphate (SDS) and 1.5% propanol at pH7. At a 6.0 g mL^–1 concentration level the peak area and peak height repeatability were 2.6 and 2.4%, respectively. The application of the proposed method to the analysis of five pharmaceutical formulations, using peak heights as the dependent variable, gave recoveries between 85 and 104% of the values declared by the manufacturers. The proposed procedure for the determination of caffeine is rapid (15 min per sample), reliable and free from interferences.