A Validated Stability Indicating LC Method for Mitotane in Bulk Drugs and Pharmaceutical Dosage Forms

A novel, sensitive, stability indicating RP-LC method has been developed for the quantitative determination of mitotane, its impurity in both bulk drugs and pharmaceutical dosage forms. Efficient chromatographic separation was achieved using a C18 stationary phase with simple mobile phase combination delivered in an isocratic mode and quantitation was by ultraviolet detection at a wavelength of 230 nm. The mobile phase consisted of buffer and acetonitrile (25:75, v/v) delivered at a flow rate of 1.0 mL min⁻¹. Buffer consisted of 10 mM potassium dihydrogen orthophosphate monohydrate, pH adjusted to 2.5 by orthophosphoric acid. In the developed LC method the resolution (R _s ) between mitotane and its impurity namely Imp-1 was found to be greater than 2.5. Regression analysis shows an r value (correlation coefficient) greater than 0.999 for mitotane and its impurity. This method was capable to detect the impurity of mitotane at a level of 0.003% with respect to test a concentration of 0.2 mg mL⁻¹ for a 10 μL injection volume. The inter- and intra-day precision values for mitotane and its impurity was found to be within 2.0% RSD. The method has shown good and consistent recoveries for mitotane in bulk drugs (99.2–101.5%), pharmaceutical dosage forms (98.2–103.1%) and for its impurity (99.7–102.1%). The test solution was found to be stable in diluent for 48 h. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in basic stress hydrolysis. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.97%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.

     

A Stability Indicating LC Method for Deferasirox in Bulk Drugs and Pharmaceutical Dosage Forms

A novel, sensitive, stability indicating RP-LC method has been developed for the quantitative determination of deferasirox, its related impurities in both bulk drugs and pharmaceutical dosage forms. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in an isocratic mode and quantitation was by ultraviolet detection at 245 nm. The mobile phase consisted of buffer, acetonitrile and methanol (50:45:5, v/v) delivered at a flow rate of 1.0 mL min^?1. Buffer consisted of 10 mM potassium dihydrogen orthophosphate monohydrate, pH adjusted to 3.0 by using orthophosphoric acid. In the developed LC method the resolution (R _s ) between deferasirox and its four potential impurities was found to be greater than 2.0. Regression analysis showed an r value (correlation coefficient) greater than 0.999 for deferasirox and its four impurities. This method was capable to detect all four impurities of deferasirox at a level of 0.002% with respect to test concentration of 0.5 mg mL^?1 for a 10 μL injection volume. The inter- and intra-day precision values for all four impurities and for deferasirox was found to be within 2.0% RSD. The method showed good and consistent recoveries for deferasirox in bulk drugs (98.3–101.1%), pharmaceutical dosage forms (100.2–103.1%) and for its all the four impurities (99.7–102.1%). The test solution was found to be stable in methanol for 48 h. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in acid stress hydrolysis. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.95%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.     

A Stability-Indicating LC Method for Analysis of Balsalazide Disodium in the Bulk Drug and in Pharmaceutical Dosage Forms

A novel, sensitive, stability-indicating gradient RP-LC method has been developed for quantitative analysis of balsalazide disodium and its related impurities both in the bulk drug and in pharmaceutical dosage forms. Efficient chromatographic separation was achieved on a C₁₈ stationary phase with a simple mobile-phase gradient prepared from methanol and phosphate buffer (10 mm potassium dihydrogen orthophosphate monohydrate, adjusted to pH 2.5 by addition of orthophosphoric acid). The mobile-phase flow rate was 1.0 mL min^?1. Quantification was achieved by use of ultraviolet detection at 240 nm. Under these conditions resolution of balsalazide disodium from its three potential impurities was greater than 2.0. Regression analysis resulted in a correlation coefficient greater than 0.99 for balsalazide disodium and all three impurities. This method was capable of detecting the three impurities at 0.003% of the test concentration of 0.3 mg mL^?1, using an injection volume of 10 μL. Inter-day and intra-day precision for all three impurities and for balsalazide disodium was within 2.0% RSD. Recovery of balsalazide disodium from the bulk drug (99.2–101.5%) and from pharmaceutical dosage forms (99.8–101.3%), and recovery of the three impurities (99.1–102.1%) was consistently good. The test solution was found to be stable in 70:30 (v/v) methanol–water for 48 h. When the drug was subjected to hydrolytic, oxidative, photolytic, and thermal stress, acidic and alkaline hydrolysis and oxidizing conditions led to substantial degradation. The RP-LC method was validated for linearity, accuracy, precision, and robustness.     

Stress Degradation Behavior of Entacapone and Development of LC Stability-Indicating Related Substances and Assay Method

A new, sensitive, stability indicating gradient RP-LC related substances and assay method has been developed for the quantitative determination of entacapone in bulk drugs. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination of buffer and acetonitrile. Buffer consisted of 0.1% orthophosphoric acid, delivered in a gradient mode and quantitation was carried out using ultraviolet detection at 220 nm with a flow rate of 1.5 mL min^?1. In the developed LC method the resolution (R _s ) between entacapone and its three potential process impurities were found to be >2.0. Regression analysis showed an r ² value (correlation coefficient) >0.99 for entacapone and its three potential impurities. This method was capable to detect all three process impurities of entacapone at a level of 0.003% with respect to test concentration of 0.5 mg mL^?1 for a 20 μL injection volume. The inter- and intra-day precision values for all three impurities and for entacapone was found to be within 2.0% RSD. The method has shown good and consistent recoveries for entacapone in bulk drugs (99.2–101.5%) and its three impurities (99.5–102.2%). The test solution was found to be stable in diluent for 48 h. The drug substances were subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in acid stress, base stress and oxidative conditions. The stressed test solutions were assayed against the qualified working standard of entacapone and the mass balance in each case was close to 99.7% indicating that the developed method was stability-indicating. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.     

A Stability Indicating LC Method for Vardenafil HCl

A simple, sensitive gradient RP-LC assay method has been developed for the quantitative determination of vardenafil HCl in bulk drug and in pharmaceutical dosage forms, used to treat erectile dysfunction. The developed method is also applicable for the related substances determination. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in a gradient mode and quantification was carried out using ultraviolet detection at a flow rate of 1.0 mL min^?1. In the developed LC method the resolution between vardenafil and its four potential impurities was found to be greater than 3.0. Regression analysis shows an r ² value (correlation coefficient) greater than 0.99 for vardenafil and its four impurities. This method was capable of detecting all four impurities of vardenafil at a level of 0.009% with respect to test concentration of 1.0 mg mL^?1 for a 10 μL injection volume. The method has shown good and consistent recoveries for vardenafil (98.4–100.6%) and its four impurities (93.5–106.2%). The test solution was found to be stable in the diluent for 48 h. Mass balance was found close to 99.4%.     

Stress Degradation Behavior of Entacapone and Development of LC Stability-Indicating Related Substances and Assay Method

A new, sensitive, stability indicating gradient RP-LC related substances and assay method has been developed for the quantitative determination of entacapone in bulk drugs. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination of buffer and acetonitrile. Buffer consisted of 0.1% orthophosphoric acid, delivered in a gradient mode and quantitation was carried out using ultraviolet detection at 220 nm with a flow rate of 1.5 mL min⁻¹. In the developed LC method the resolution (R _s ) between entacapone and its three potential process impurities were found to be >2.0. Regression analysis showed an r ² value (correlation coefficient) >0.99 for entacapone and its three potential impurities. This method was capable to detect all three process impurities of entacapone at a level of 0.003% with respect to test concentration of 0.5 mg mL⁻¹ for a 20 μL injection volume. The inter- and intra-day precision values for all three impurities and for entacapone was found to be within 2.0% RSD. The method has shown good and consistent recoveries for entacapone in bulk drugs (99.2–101.5%) and its three impurities (99.5–102.2%). The test solution was found to be stable in diluent for 48 h. The drug substances were subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in acid stress, base stress and oxidative conditions. The stressed test solutions were assayed against the qualified working standard of entacapone and the mass balance in each case was close to 99.7% indicating that the developed method was stability-indicating. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.

     

Development and Validation of a Stability-Indicating LC Method for the Determination of Rupatadine in Pharmaceutical Formulations

A reversed-phase liquid chromatography (RP-LC) method was validated for the determination of rupatadine in pharmaceutical dosage forms. The LC method was carried out on a Gemini C₁₈ column (150 mm × 4.6 mm I.D.), maintained at 30 °C. The mobile phase consisted of ammonium acetate buffer (pH 3.0; 0.01 M) with 0.05% of 1-heptanesulfonic acid–acetonitrile (71.5:28.5, v/v), run at a flow rate of 1.0 mL min^?1 and using photodiode array (PDA) detection at 242 nm. The chromatographic separation was obtained with retention time of 5.15 min, and was linear in the range of 0.5–400 μg mL^?1 (r ² = 0.9999). The specificity and stability-indicating capability of the method was proven through the degradation studies and showing also, that there was no interference of the excipients. The accuracy was 100.39% with bias lower than 0.58%. The limits of detection and quantitation were 0.01 and 0.5 μg mL^?1, respectively. Moreover, method validation demonstrated acceptable results for precision, sensitivity and robustness. The proposed method was applied for the analysis of pharmaceutical dosage forms assuring the therapeutic efficacy.     

Simultaneous Determination of Etodolac and Acetaminophen in Tablet Dosage Form by RP-LC

A simple, specific, precise and accurate reverse phase liquid chromatographic (RP-LC) method has been developed for the simultaneous determination of etodolac and acetaminophen in tablet dosage form. The chromatographic separation was achieved on a BDS Hypersil C18, 100 mm × 4.6 mm, 5 μm column at a detector wavelength of 274 nm using an isocratic mobile phase consisting of a mixture of 0.05% aqueous orthophosphoric acid and acetonitrile in the ratio of 50:50 (v/v) at a flow rate of 1.0 mL min^?1. The retention times for etodolac and acetaminophen were found to be 1.32 and 4.24 min, respectively. The method was validated for the parameters like specificity, linearity, precision, accuracy and robustness. The method was found to be specific and stability indicating as no interfering peaks of impurities, degradent and excipients were observed. The square of correlation coefficients (R ²) for etodolac and acetaminophen were 0.9996 and 0.9998 while percentage recoveries were 101.32 and 100.94%, respectively. Intra- and inter-day relative standard deviations for both the components were <2.0%. The proposed RP-LC method can be applied for the routine analysis of commercially available formulations of these drugs either as such or in combination.     

Enantiomeric Separation of Moxifloxacin and Its (R,R)-Isomer by Ligand-Exchange Chiral Chromatography

A new stereospecific LC method for the separation and quantification of moxifloxacin and its (R,R)-enantiomer in bulk drug was developed and validated by ligand-exchange liquid chromatography on a reversed phase column using aqueous mobile phase containing the chiral reagent l-isoleucine-Cu(II). The UV detector was operated at 293 nm. The flow rate of mobile phase was set at 0.9 mL min^?1. The achiral ODS column offers good separation of the two enantiomers in less than 20 min. The test concentration was 1,000 μg mL^?1 in the mobile phase. This method was capable of detecting the (R,R)-enantiomer of moxifloxacin up to 0.1 μg mL^?1 for a 20 μL injection volume. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. There was no interference of degradants with the (R,R)-enantiomer in the developed method. The developed chiral RP-LC method was validated with respect to linearity, accuracy, precision and robustness. The percentage recovery for the (R,R)-enantiomer in bulk drug samples ranged from 98.1 to 104.4%. The test solution was found to be stable in the mobile phase for 48 h after preparation.     

Stress Degradation Behavior of Desipramine Hydrochloride and Development of Suitable Stability-Indicating LC Method

A simple reverse phase liquid chromatographic method was developed for the quantitative determination of desipramine hydrochloride and its related impurities in bulk drugs which is also stability-indicating. During the forced degradation at hydrolysis, oxidative, photolytic and thermal stressed conditions, the degradation results were only observed in the oxidative stress condition. The blend of the degradation product and potential impurities were used to optimize the method by an YMC Pack Pro C₁₈ stationary phase. The LC method employs a linear gradient elution with the water–acetonitrile–trifluoroacetic acid as mobile phase. The flow rate was 1.0 mL min^?1 and the detection wavelength 215 nm. The stressed samples were quantified against a qualified reference standard and the mass balance was found close to 99.0% (w/w) when the response of the degradant was considered to be equal to the analyte (i.e. desipramine). The developed RP-LC method was validated in agreement with ICH requirements.     

Development of the HPLC Method for Simultaneous Determination of Lidocaine Hydrochloride and Tribenoside Along with Their Impurities Supported by the QSRR Approach

A new liquid chromatographic (LC) method for simultaneous determination of lidocaine hydrochloride (LH) and tribenoside (TR) along with their related compounds in pharmaceutical preparations is described. Satisfactory LC separation of all analytes after the liquid–liquid extraction (LLE) procedure with ethanol was performed on a C₁₈ column using a gradient elution of a mixture of acetonitrile and 0.1 % orthophosphoric acid as the mobile phase. The procedure was validated according to the ICH guidelines. The limits of detection (LOD) and quantification (LOQ) were 4.36 and 13.21 μg mL^?1 for LH, 7.60 and 23.04 μg mL^?1 for TR, and below 0.11 and 0.33 μg mL^?1 for their impurities, respectively. Intra- and inter-day precision was below 1.97 %, whereas accuracy for all analytes ranged from 98.17 to 101.94 %. The proposed method was sensitive, robust, and specific allowing reliable simultaneous quantification of all mentioned compounds. Moreover, a comparative study of the RP-LC column classification based on the quantitative structure-retention relationships (QSRR) and column selectivity obtained in real pharmaceutical analysis was innovatively applied using factor analysis (FA). In the column performance test, the analysis of LH and TR in the presence of their impurities was carried out according to the developed method with the use of 12 RP-LC stationary phases previously tested under the QSRR conditions. The obtained results confirmed that the classes of the stationary phases selected in accordance with the QSRR models provided comparable separation for LH, TR, and their impurities. Hence, it was concluded that the proposed QSRR approach could be considered a supportive tool in the selection of the suitable column for the pharmaceutical analysis.     

RP-LC Determination and Pharmacokinetic Study of Ferulic Acid and Isoferulic Acid in Rat Plasma After Taking Traditional Chinese Medicinal-Preparation: Guanxinning Lyophilizer

A sensitive, simple, and accurate method for determination and pharmacokinetic study of ferulic acid and isoferulic acid in rat plasma was developed using a reversed-phase column liquid chromatographic (RP-LC) method with UV detection. Sample preparations were carried out by protein precipitation with the addition of methanol, followed by evaporation to dryness. The resultant residue was then reconstituted in mobile phase and injected into a Kromasil C₁₈ column (250 × 4.6 mm i.d. with 5 μm particle size). The mobile phase was methanol-1% formic acid (33:67, v/v). The calibration plots were linear over the range 5.780–5780 ng·mL^?1 for ferulic acid and 1.740–348.0 ng·mL^?1 for isoferulic acid. Mean recoveries were 85.1% and 91.1%, respectively. The relative standard deviations (RSDs) of within-day and between-day precision were not above 15% for both of the analytes. The limits of quantification were 5.780 ng·mL^?1 for ferulic acid and 1.740 ng·mL^?1 for isoferulic acid. This RP-LC method was used successfully in pharmacokinetic studies of ferulic acid and isoferulic acid in rat plasma after intravenous injection of Guanxinning Lyophilizer.     

Determination of Dimenhydrinate Nasal Delivery System in the Blood by RP-LC

Dimenhydrinate (DM) is used therapeutically for the prevention of motion sickness associated with nausea and vomiting. The aim of this investigation is the development of a new, rapid, sensitive, simple and fully validated RP-LC procedure for the suitable assay of DM in pharmaceutical formulation applied in blood samples. The method was validated before the amount determination studies in order to confirm linearity, precision, accuracy, selectivity, determination and quantification limit and consistency. High determination coefficient (r ²  = 0.998) of the standard curve drawn in the linearity studies showed that the line equation can be used in the quantification of the DM. Literature was reviewed for the methods based on diphenhydramine (DIP), its metabolite dimenhydrinate, in the in vivo determination of dimenhydrinate amount. The most appropriate method to be used in LC was decided to be the method applied by benefitting from the fluorescence characteristic of DIP. Maximum excitation and emission wavelengths in the developed method were scanned using multiple wavelengths and, maximum excitation and emission wavelengths were found to be 215 and 300 nm, respectively. In the validation study used to prove validity of the method, determination coefficient of the developed standard curve was calculated as 0.998 (RSD %), and line equation was concluded to be appropriate for use in amount determination studies. BBS % (1.06, 1.84 %) values obtained as “<2 %” in the intra-day and inter-day precision studies proved the precision of the method. Selectivity study revealed that other materials used in the formulation did not exhibit absorbance in the same wavelengths. Detection and quantification limit were found as 1 and 5 ng mL^?1, respectively. The determination of DM plasma concentrations using the proposed and fully validated LC assay has allowed us to characterize DMPK in the sheep, as well as determine DM relative bioavailability.     

A Validated Stability-Indicating LC Method for Zonisamide

A simple, isocratic, rapid, and accurate reversed-phase high-performance liquid chromatographic method has been established for quantitative determination of zonisamide. The method is also applicable to determination of related substances in the bulk drug. Chromatographic separation was achieved on a 250 mm × 4.6 mm, 5-μm particle, C₁₈ column; the mobile phase was a 70:30 (v/v) mixture of 0.1% (v/v) aqueous triethylamine, adjusted to pH 2.5 with dilute orthophosphoric acid, and acetonitrile. Chromatographic resolution of zonisamide from its potential impurity, A, was found to be >2. The limits of detection and quantification of zonisamide and impurity A were 0.04 and 0.12 μg mL^?1, respectively, for 20 μL injection volume. Recovery of zonisamide ranged from 98.5 to 101.2% and recovery of impurity A from a sample of zonisamide ranged from 97.4 to 102.7%. The method was validated for linearity, accuracy, precision, and robustness.     

Development and Validation of a Stability Indicating LC Method for the Determination of Faropenem in Pharmaceutical Formulations

A simple, selective and sensitive stability indicating LC method has been developed and validated for the determination of faropenem in bulk drug and pharmaceutical formulations in the presence of degradation products. The separation was achieved by using an isocratic mobile phase mixture of acetate buffer of pH 3.5 and methanol (65:35, v/v) and 250 mm × 4.6 mm I.D., 5 μm particle size SGE make Wakosil C-18 AR column at flow rate of 1.0 mL min^?1 with detection at 305 nm. The retention time of faropenem is 6.63 min and was linear in the range of 5–75 μg mL^?1 (r = 0.9999). The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation and was found to be unstable in all the stress conditions. The proposed method was successfully employed for quantification of faropenem in bulk drug and its pharmaceutical formulations.     

Simultaneous Determination of Clobetasol Propionate and Calcipotriol in a Novel Fixed Dose Emulgel Formulation by LC-UV

A new, rapid, selective, cheap and simple RP-LC method has been developed and validated for the simultaneous determination of clobetasol propionate and calcipotriol mixtures in bulk drugs (raw materials) and in a novel-fixed dose emulgel formulation. Separation was carried out using a NovaPak C18 column with methanol:water (74:26 v/v) as mobile phase for isocratic elution at a flow rate of 1.0 mL min^?1. The column temperature was set at 25 °C. Calibration curves were established ranging between 0.5 and 20 μg mL^?1 and 0.5 and 10 μg mL^?1 for clobetasol propionate and calcipotriol, respectively. Limit of detection and limit of quantification values of the method was found as 0.16 and 0.48 μg mL^?1 for clobetasol propionate and 0.10 and 0.30 μg mL^?1 for calcipotriol, respectively. The method was validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective and sensitive for the simultaneous analysis of clobetasol propionate and calcipotriol. The proposed method can be easily applied for the simultaneous determination of clobetasol propionate and calcipotriol in prepared emulgel formulations. The obtained validation results showed that the RP-LC method is suitable for routine quantification of clobetasol propionate and calcipotriol in emulgel formulations with high precision and accuracy.     

Development and Validation of a Stability-Indicating LC Method for the Determination of Rupatadine in Pharmaceutical Formulations

A reversed-phase liquid chromatography (RP-LC) method was validated for the determination of rupatadine in pharmaceutical dosage forms. The LC method was carried out on a Gemini C₁₈ column (150 mm × 4.6 mm I.D.), maintained at 30 °C. The mobile phase consisted of ammonium acetate buffer (pH 3.0; 0.01 M) with 0.05% of 1-heptanesulfonic acid–acetonitrile (71.5:28.5, v/v), run at a flow rate of 1.0 mL min⁻¹ and using photodiode array (PDA) detection at 242 nm. The chromatographic separation was obtained with retention time of 5.15 min, and was linear in the range of 0.5–400 μg mL⁻¹ (r ² = 0.9999). The specificity and stability-indicating capability of the method was proven through the degradation studies and showing also, that there was no interference of the excipients. The accuracy was 100.39% with bias lower than 0.58%. The limits of detection and quantitation were 0.01 and 0.5 μg mL⁻¹, respectively. Moreover, method validation demonstrated acceptable results for precision, sensitivity and robustness. The proposed method was applied for the analysis of pharmaceutical dosage forms assuring the therapeutic efficacy.

     

Development of a New Analytical Method for Determination of Related Components in Nateglinide

An isocratic reverse phase liquid chromatographic (RP-LC) assay method has been developed for the quantitative determination of nateglinide and its related components namely imp-1 and imp-2 in bulk drug and in pharmaceutical dosage form, used for the treatment of type II diabetes mellitus. The developed method is stability indicating and also can be used for stability testing. The chromatographic separation was achieved on C-8, 150 × 4.6 mm, 3.5 μm stationary phase. The LC method employs solution A as mobile phase. Solution A contains a mixture of phosphate buffer pH 3.0: acetonitrile (50:50 v/v). The flow rate was 1.0 mL min⁻¹ and the detection wavelength was 210 nm. In the developed LC method the resolution between nateglinide and its potential impurities namely imp-1 and imp-2 was found to be greater than 5.0. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in acid medium, alkaline medium and oxidative stress conditions. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.2%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.     

Evaluation of a Vancomycin-Based LC Column in Enantiomeric Separation of Atenolol: Method Development, Repeatability Study and Enantiomeric Impurity Determination

An LC method was developed and validated for the enantioselective separation and enantiomeric impurity quantitation of atenolol. Separation of the atenolol enantiomers on the Chirobiotic V2 (150 mm × 4.6 mm, 5 μm) column was best achieved using a ternary mobile phase of methanol–acetonitrile-triethylamine acetate 0.5% (w/v), pH 4.5 in a ratio of (45:50:5; v/v/v). Good resolution value of R _s  = 3 was obtained at a flow rate of 1 mL min^?1 within a total run time of less than 40 min. Peak identification was achieved using the standard reference of individual enantiomers. The peak of the impurity was eluted in front of the peak of the main enantiomer. Detection was performed by UV at 226 nm. Within and between day’s repeatabilities for both retention time and peak area were investigated at three concentration levels and found to be low. The method was also found to be efficient for the determination of atenolol enantiomeric impurity. An impurity quantitation level of (R)-atenolol down to 0.08% relative to the main enantiomer (S)-atenolol was found possible.     

Stability-Indicating LC Method for Analysis of Lornoxicam in the Dosage Form

A simple, rapid, and precise method has been developed for quantitative analysis of lornoxicam (Lxm) in pharmaceutical dosage forms. Chromatographic separation of Lxm and its degradation products was achieved on a C₁₈ analytical column with 0.05% (v/v) aqueous trifluoroacetic acid–acetonitrile, 70:30 (v/v), as mobile phase. The flow rate was 1.0 mL min^?1, the column temperature 30 °C, and detection was by absorption at 295 nm using a photodiode-array detector. The number of theoretical plates and tailing factor for Lxm were 6,577 and 1.03, respectively. Lxm was exposed to thermal, photolytic, hydrolytic, and oxidative stress, and the stressed samples were analysed by use of the proposed method. Peak homogeneity data for Lxm in the chromatograms from the stressed samples, obtained by use of the photodiode-array detector, demonstrated the specificity of the method for analysis of Lxm in the presence of the degradation products. The linearity of the method was excellent over the range 10–200 μg mL^?1 Lxm. The correlation coefficient was 0.9999. Relative standard deviations of peak areas from six measurements were always less than 2%. The proposed method was found to be suitable and accurate for quantitative analysis of Lxm and study of its stability.