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Summary

A simple, selective, precise, and stability-indicating thin-layer chromatographic method has been developed and validated for analysis of some angiotensin II receptor antagonists (AIIRAs), namely, Losartan potassium (Los-K), Irbesartan (Irb), and Candesartan cilexetil (Cand) in the bulk drug and in pharmaceutical formulations (tablets). The method was based on using TLC plates pre-coated with silica gel G 60 on aluminum sheets as stationary phase and the development system was performed using chloroform:methanol (9:1) giving well separated and compact spots for all the studied drugs (R F values 0.41–0.53). The separated spots were characterized by viewing under the UV lamp, then visualized as orange spots by spraying with Dragendorff's reagent and measured by densitometry. Under the optimum chromatographic conditions, linear relationships were obtained between response and concentrations of each studied drug with high correlation coefficients (0.9985–0.9994). Good accuracy and precision were successfully obtained for the analysis of tablets containing each drug alone or combined with diuretic drug hydrochlorothiazide (HCTZ). No interferences could be observed from the co-formulated HCTZ, commonly encountered excipients present in tablets as well as the degradation products. The results were compared successfully with reported methods and can be used as a stability-indicating assay.

Open access

Summary

A simple, sensitive, specific, precise, and stability-indicating high-performance liquid chromatographic (HPLC) method for determination of cefpodoxime proxetil as bulk drug and as pharmaceutical formulation was developed and validated as per the International Conference on Harmonization (ICH) guidelines. An isocratic separation was achieved using a Phenomenex Luna C18 (250 mm × 4.6 mm i.d., 5 μm particle size) column with a flow rate of 1 mL min−1 and a UV detector to monitor the eluate at 254 nm. The mobile phase consisted of acetonitrile and 50 mM ammonium acetate pH 6 (pH was adjusted with o-phosphoric acid) in the ratio of 45:55 (υ/υ). The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.9998 in the working concentration range of 1–80 μg mL−1. The LOD and LOQ were 0.17 and 0.5 μg mL−1, respectively. The drug was subjected to acid and alkali hydrolysis, oxidation, dry heat, wet heat treatment, and photodegradation. The standard drug peaks were well resolved from the degradation products' peaks with significantly different retention time (t R), and the resolution factor for cefpodoxime proxetil was found to be greater than 1.7. As the method could effectively measure the drug in the presence of all degradation products and excipients expected to be present in the formulation, it can be employed as a specific stability-indicating method. Moreover, the proposed HPLC method was utilized to investigate the kinetics of the acidic and oxidative degradation processes at different temperatures. An Arrhenius plot was constructed and the apparent pseudo-first-order rate constant, half-life and activation energy were calculated.

Open access

Linaclotide, a first-in-class guanylate cyclase-C agonist, was recently approved by US Food and Drug Administration (FDA) as a promising pharmacotherapy for the management of constipation-predominant irritable bowel syndrome (IBS). In this communication, we present a novel stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method for the quantitative determination of linaclotide along with its degradation products. During the International Conference on Harmonization (ICH) prescribed stress study, linaclotide was found susceptible to degrade under hydrolytic (acid and base) and oxidative (peroxide) conditions. The separation of the degradants from the analyte was achieved on a Zorbax Eclipse XDB C8 Column (250 mm × 4.6 mm, 5 μm) using 0.01 N potassium dihydrogen orthophosphate buffer and acetonitrile (80:20 v/v) as mobile phase at a flow rate of 1.00 mL min−1 at column temperature of 40 °C. The detection of the column effluents was realized on a photodiode array detector set at 220 nm. Under the above optimal condition, the method was validated with respect to specificity, linearity, range, precision, robustness, and sensitivity in compliance to the regulatory requirements.

Open access

Summary

A sensitive, selective, precise, and stability-indicating HPTLC method has been established for analysis of amtolmetin guacil both as the bulk drug and in a formulation. Aluminum foil-backed silica gel 60F254 plates were used with toluene-ethyl acetate 4:6 (υ/υ) as mobile phase, and densitometric analysis was performed in absorbance mode at 320 nm. The method was validated for linearity, precision, accuracy, selectivity, and specificity in accordance with ICH guidelines. Amtolmetin guacil was subjected to acidic and alkaline hydrolysis, oxidation, dry heat treatment, and photo-degradation. The method was used to study the kinetics of degradation of amtolmetin guacil by acid and alkali.

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Summary

A new, sensitive, stability-indicating, and cost and time-effective isocratic reversed-phase UHPLC method has been developed for quantitative analysis of felbamate, an antiepileptic drug, both in the bulk drug and in pharmaceutical dosage forms. Chromatographic separation of felbamate and its two impurities was achieved on a C18 column with a simple buffer-methanol mobile phase; the run time was 8 min. Quantification was achieved by ultraviolet detection. Resolution between the impurities was >2.0. Response was a linear function of concentration over the range 0.1–3.0 μg mL−1, correlation coefficient >0.999, for felbamate and the impurities. The method is capable of detecting the two impurities at levels of 0.002% (0.02 μg mL−1) of the test concentration of 1.0 mg mL−1 (1 μL injection). The same sensitivity was achieved for all the degradation products formed during stress studies in which the drug was subjected to hydrolysis, oxidation, photolysis, and thermal degradation. Substantial degradation occurred under acidic and basic conditions. The stressed test solutions were assayed against felbamate working standard and the mass balance in each case was close to 100%, indicating the method is stability-indicating. The method was validated for linearity, accuracy, precision, and robustness in accordance with ICH Guidelines.

Open access

Summary

Stability-indicating HPLC method was developed for determination of solifenacin succinate (SLN) as bulk drug and from pharmaceutical formulation. The HPLC separation of SLN from its degradation products was achieved using Oyster BDS C8 (250 mm × 4.6 mm i.d., 5 μm particle size) column with a flow rate 0.7 mL min−1 and using a UV detector to monitor the eluate at 210 nm. The mobile phase was composed of 10 mM ammonium formate buffer (adjusted pH 3 with formic acid)-acetonitrile-methanol (52.5:37.5:10, v/v/v). The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.9999 in the working concentration range of 2–100 μg mL−1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.07 and 0.21 μg mL−1, respectively. API and formulation of SLN were subjected to acid and alkali hydrolysis, oxidation, thermal and photodegradation. Standard drug peak was well resolved from the peaks of degradation products with significantly different retention time values. Also, isolation and identification of major base degradation product were carried out. The method is simple, accurate, specific, repeatable, stability-indicating, reduces the duration of the analysis and is suitable for routine determination of SLN in pharmaceutical formulation.

Open access

Summary

A stability-indicating HPLC method has been developed for analysis of tolterodine tartrate in the bulk drug and in formulations. Acceptable separation of the drug and its degradation products was achieved at 40°C on a 4.6 mm i.d. × 250 mm, 5-μm particle, C18 column with 40:60 (υ/υ) buffer solution-methanol containing 0.5% (υ/υ) triethylamine as mobile phase. The pH of the mobile phase was adjusted to 7.0 ± 0.1 with orthophosphoric acid. The flow rate was 1.2 mL min−1 and the detection wavelength 220 nm. The method was validated for linearity, precision, accuracy, specificity, and robustness. Response was a linear function of concentration over the range 1–100 μg mL−1. The slope of the calibration plot was 17.82 mV s−1 ppm−1, the correlation coefficient 0.999, and the relative standard deviation (RSD) 0.23%. Assessment of precision revealed method RSD was low — from 1.59 to 1.88% for intra-day precision and from 0.59 to 1.90% for inter-day precision. Stress degradation studies showed tolterodine tartrate was stable to acidic and neutral hydrolysis, oxidative stress, photolytic stress, and thermal stress but labile to alkaline hydrolysis.

Open access

Summary

A new, specific, sensitive, selective, precise, and reproducible high-performance thin-layer chromatographic (HPTLC) method has been established for study of the stability of 3-acetyl-11-keto-β-boswellic acid (AKBA). HPTLC was performed on aluminium foil plates coated with 200 μm silica gel 60F254. Linear ascending development with toluene-ethyl acetate 7:3 (v/v) was performed at room temperature (25 ± 2°C) in a twin-trough glass chamber saturated with mobile phase vapour. Compact bands (R F 0.52 ± 0.02) were obtained for AKBA. Spectrodensitometric scanning was performed in absorbance mode at 250 nm. Linear regression analysis of the calibration plots showed there was a good linear relationship (r 2 = 0.9989 ± 0.0002) between peak area and concentration in the range 200–1200 ng band−1. The method was validated for precision, recovery, robustness, specificity, and detection and quantification limits, in accordance with ICH guidelines. The limits of detection and quantification were 3.06 and 9.29 ng band−1, respectively. The recovery of the method was 99.35–100.21%. AKBA was subjected to various stress test conditions — acid and alkali hydrolysis, oxidation, photodegradation, and dry and wet heat treatment. Degradation products were well resolved from the pure drug with significantly different R F values. Statistical analysis showed the method could be successfully applied for the estimation of AKBA in herbal extract and in nanoparticles. Because the method could effectively separate the drug from its degradation products, it can be regarded as stability-indicating.

Open access

Summary

A simple, selective, precise and stability-indicating high-performance thin-layer chromatographic method for analysis of rupatadine fumarate, both as the bulk drug and in a tablet formulation, has been developed and validated. Aluminium foil TLC plates precoated with silica gel 60F254 were used as stationary phase and toluene-methanol-triethylamine 4:1:0.2 (v/v) as mobile phase. A compact band (R F 0.61 ± 0.02) was obtained for rupatadine fumarate. Densitometric analysis was performed in absorbance mode at 264 nm. Linear regression analysis revealed a good linear relationship (r 2 = 0.9992 ± 0.0001) between peak area and concentration in the range 400–1400 ng band−1. The mean values ± SD of the slope and intercept were 2.5471 ± 0.005 and 1055.2 ± 4.20, respectively. The method was validated for precision, recovery, and robustness. The limits of detection and quantitation were 66.63 and 201.91 ng band−1, respectively. Rupatadine fumarate was subjected to acid and alkaline hydrolysis, oxidation, and photochemical and thermal degradation and underwent degradation under all these conditions. Statistical analysis proved the method enables repeatable, selective, and accurate analysis of the drug. It can be used for identification and quantitative analysis of rupatadine fumarate in the bulk drug and in tablet formulations.

Open access

A simple stability-indicating high-performance liquid chromatography-diode array detection (HPLC-DAD) method has been developed for the simultaneous determination of triamterene (TRI) and xipamide (XIP) in presence of the degradation products generated in studies of forced decomposition. Drugs were subjected to stress by hydrolysis (acidic, alkaline, and neutral), oxidation, photolysis (254 and 365 nm), and dry and wet heat treatments. Degradation occurs under acidic and alkaline conditions (TRI only), oxidative stress (TRI and XIP), and by photolysis (XIP only), but both drugs were stable under other stress conditions investigated. Separation of the two drugs from all the degradant peaks was achieved within 11 min using C8 column (250 × 4.6 mm, 5 μm) and mobile phase consisting of acetonitrile and 0.05 M phosphate buffer adjusted to pH 4 delivered at a flow rate of 1 mL min−1 using gradient elution system. The drugs were quantified at 220 nm using photodiode array detector, based on peak area. Peak homogeneity of the two drugs was checked using diode array detector, and the purity angle was within the purity threshold limit in all of the stressed samples. The calibration graphs for each drug were rectilinear in the range of 0.2–50 and 0.1–20 μg mL−1 for TRI and XIP, respectively. The method was validated in compliance with International Conference on Harmonization (ICH) guidelines; in terms of linearity, accuracy, precision, robustness, limit of detection, and limit of quantitation. The proposed method was successfully applied for the determination of the investigated drugs in their tablet without interference from excipients with acceptable accuracy and precision; the label claim percentages were 100.23 ± 0.70% and 100.75 ± 1.11% for TRI and XIP, respectively.

Open access