Mean Percentage Recoveries Research Articles

Biosynthesized silver nanoparticle-coated electro-membrane extraction of perchlorate in different seafood samples.

In this work we developed a rapid and straightforward technique in which biosynthesized silver nanoparticles (Ag-NPs) were coated on a porous membrane utilizing electrical potential to extract perchlorate from seafood samples. The biosynthesized Ag-NPs were well characterized using UV-Vis. spectrophotometry, X-ray diffraction, and scanning electron microscopy. After extraction, analyses were performed using ion chromatography. The Ag-NP-coated porous polypropylene membrane shows higher extraction efficiency due to the high electrical conductivity of the Ag-NPs. The performance of this efficient technique was compared with those previously reported in the literature. The extraction variables that affect extraction of the target analyte and influence percentage recovery, such as pH of the sample solution, extraction time, and applied voltage, were investigated and optimized. The results demonstrated optimum conditions to achieve low detection limits [LODs (limits of detection)]: sample solution (pH =6), short extraction time (10min), and applied voltage (5V). The developed method shows excellent linearity for perchlorate ion in the range from 0.001 to 350 μg L-1 with a coefficient of determination (r2 ) of 0.9991. The detection limit (LODs) and quantification limits (limits of quantification) were found to be 0.04 and 0.1225 μg kg-1 , respectively. The mean recovery percentages for three replicates of 10 different spiked fish samples by 3μg g-1 of perchlorate were between 92.2 and 106.2%, with an observed relative standard deviation in the range of 0.8-3.7%. The proposed method is rapid, sensitive, inexpensive, environmentally friendly, and highly effective in extracting perchlorate from different seafood samples.

Validated RP-LC Methods for Investigating the Degradation Behavior of Acefylline: Application for Analysis in Two Binary Mixtures

Background: Acefylline (Acef) is a derivative of theophylline that has bronchodilator effects. Two binary mixtures were marketed for Acef: Acefylline piperazine/ Phenobarbitone (Acef-P/Phen) and Acefylline heptaminol/ Cinnarizine (Acef-H/ Cinn). To our knowledge none of the reported methods had the capacity to determine Acef in its binary mixture in presence of its degradation products and potential impurity theophylline (Theo). Methods: Two validated RP-LC methods were established for the determination of Acef-P/Phen and Acef-H/ Cinn in presence of Acef degradation products and its potential impurity Theo. A complete study of the forced acidic, alkaline and oxidative degradation of Acef was presented. The methods were based on LC separation on RP C18 columns using isocratic and gradient elution for Acef-P /Phen and Acef-H /Cinn mixtures, respectively. Different chromatographic conditions were examined and optimized. Results: Linear responses were attained over concentration ranges of 75-500/15-1000 μg/mL and 100-1000 /50- 500 μg/mL with mean percentage recoveries of (100.72±1.23)%/ (99.29±1.12)% and (100.44±1.27)%/ (99.01±0.97)% for Acef-P/Phen and Acef-H /Cinn, respectively. ICH guidelines were used for methods validation and all parameters were found to be acceptable. Conclusion: The methods showed to be accurate, precise and specific for the analysis of Acef-P/Phen and AcefH /Cinn in drug substance, drug product and in laboratory prepared mixtures in presence of Theo and up to 50% of degradation products. The structures of the main degradation products and the expected degradation pathway were suggested using the MS data.

The Validation and Development of Analytical Technique for the Fast and Economical Evaluation of Amoxicillin in Solid Dosage form Through UV/Visible Spectroscopy

Objective: The key objective of the study is to explore the sensitive, rapid, simple, accurate and economic UV/Vis spectrophotometric method to determine the amount of Amoxicillin trihydrate (AMTR) in bulk pharmaceuticals and in various formulations including dry powder (syrup), tablets and capsules by employing Copper sulphate buffer solution.
 Methodology: The current spectroscopic analysis performed with 12.5 μg/ml concentration of AMTR at 320 nm follows the Beer’s Lambert Law. The linearity range (10-15µg/ml) and regression data presented a significant correlation coefficient (r2 =0.999). The appropriate level of accuracy, precision, linearity, and mean percentage recovery of AMTR were found adequate relating to the % age error and standard deviations.
 Results: Amoxicillin trihydrate and its known strengths were scanned and analyzed by our validated method such as; 10.0 µg/ml Amoxicillin (80%), 11.25 µg/ml Amoxicillin (90%), 12.5 µg/ml Amoxicillin (100%), 13.75 µg/ml Amoxicillin (110%) and 15.0 µg/ml Amoxicillin (120%).
 Conclusions: As the recommended protocol of amoxicillin determination (spectrophotometry) is accurate, precise and statistically evaluated, therefore it could readily be employed for qualitative purposes of either for the raw material and pharmaceutical preparations.

Translation of Carbon Dot Biosensors into an Embedded Optical Setup for Spoilage and Adulteration Detection

This research demonstrates a carbon quantum dot (CQD) based fluorescence technique for milk quality assessment and detection of urea adulteration using a commercialized optical fiber spectrometer (OFS) and a developed color sensor device (CSD). The change in pH from the normal pH of milk (∼6.7) indicates spoilage. The CQDs were synthesized using phthalic acid (carbon source) and triethylenediamine (TED) (passivant). The CQDs were found to be sensitive in the pH range 3–10 with a quantum yield of about 18.9%. The accuracy of spoilage detection using CQDs was expressed in the form of mean percent recovery and found to be 99.2% (R2 = 0.97) by the OFS and 99.59% (R2 = 0.98) by the CSD. The mean percent recovery obtained for urea adulteration in milk was 103.0% (R2 = 0.98) by the OFS and 97.9% (R2 = 0.97) by the CSD. The results indicate that CQDs have excellent potential for use as biosensors for spoilage and adulteration detection.

Development and validation of reversed phase high performance liquid chromatography (RP-HPLC) for quantification of captopril in rabbit plasma

AbstractTh accurate rapid, simple and selective reversed phase high performance liquid chromatography (RP-HPLC) has been established and validated for the determination of captopril (CAP). Chromatographic separation was accomplished using prepacked ODSI C18 column (250 mm × 4.6 mm with 5 μm particle size) in isocratic mode, with mobile phase consisting of water: acetonitrile (60:40 v/v), pH adjusted to 2.5 by using 85% orthophosphoric acid at a flow rate of 1 mL/min and UV detection was performed at 203 nm. RP-HPLC method used for the analysis of CAP in mobile phase and rabbit plasma was established and validated as per ICH-guidelines. It was carried out on a well-defined chromatographic peak of CAP was established with a retention time of 4.9 min and tailing factor of 1.871. The liquid–liquid extraction method was used for extraction of CAP from the plasma. Excellent linearity (R2 = 0.999) was shown over range 3.125–100 µg/mL with mean percentage recoveries ranges from 97 to 100.6%. Parameters of precision and accuracy of the developed method meet the established criteria. Intra and inter-day precision (% relative standard deviation) study was also performed which was less than 2% which indicate good reproducibility of the method. The limit of detection (LOD) and quantification for the CAP in plasma were 3.10 and 9.13 ng/mL respectively. The method was suitably validated and successfully applied to the determination of CAP in rabbit plasma samples.

Quantitative Spectrophotometric Estimation of Prednisolone in Tablet Dosage Form Using Eco-friendly Green Solvent and by applying Beer-Lambert’s Law Mathematical Equation Method

Prednisolone is a widely used synthetic glucocorticoid drug used in the treatment of allergies, inflammatory conditions, auto-immune disorders, acute and chronic obstructive pulmonary disease, rheumatoid arthritis, systemic lupus erythematosus, dermatitis, eye inflammation, asthma and multiple sclerosis. A simple and economical method was developed using eco-friendly green solvent. In this developed method the eco-friendly green solvent used was ethanol which is available easily. The method was projected to quantitative estimation and assay of Prednisolone in Prednisolone dispersible tablet dosage form. The amount and percent label claim of Prednisolone in tablet dosage form was estimated using Beer-Lambert’s law. Specific absorbance (A1%1cm) of Prednisolone is 415 at lambda max of 243 nm. The method developed was validated as per ICH guidelines. The proposed method was found to be simple, accurate, sensitive, precise, linear and rugged. The method obeys Beer-Lambert’s Law in the concentration range of 2.5-20μg/mL, as the r2 value was found to be 1.000. The mean percent recovery was found to be within acceptable range as per ICH guidelines. Hence the developed method can be used in regular quantitative analysis. The developed method acquires only one green solvent, low cost analytical equipment and the percent label claim can be calculated in the assay of Prednisolone tablets without using any standards solution or standard graph by just employing specific absorbance value in Beer-Lambert’s law, thereby concentration of drug can be calculated. As this method is simple, economical and eco-friendly it can be used elegantly and routinely in analytical laboratories and industries for estimation of Prednisolone in tablet formulation.

Smart UV-Spectrophotometric methods for the simultaneous determination of amprolium-HCl, ethopabate and sulfaquinoxaline-Na in combined dosage forms

Two UV-spectrophotometric methods were adopted for simultaneous determination of amprolium HCl, ethopabate and sulfaquinoxaline-Na. The two methods are a double divisor ratio derivative method and ratio dual wavelength method. The three cited drugs were determined by the suggested methods in the range of 6.0-50.0 µg mL-1, 2.0-27.0 μg mL-1 and 3.0-25.0 µg mL-1, respectively. The proposed methods were proved to be selective where the mean percentage recoveries of amprolium HCL, ethopabate and sulfaquinoxaline-Na provided by the double divisor ratio derivative method were 99.29 ± 0.84, 100.36 ± 1.21 and 100.61-101.57 ± 0.15-1.75; respectively. The ratio dual wavelength method mean recoveries were in the range of 98.93-100.45%±0.44-1.42, 99.47-100.67%±0.83-1.65 and 99.97-101.71%±0.10-1.15 for the studied drugs; respectively. Both methods were validated following ICH guidelines. Successful application of the methods for analyzing the three drugs in their veterinary dosage forms; Ampoethoquinone powder was conducted. The obtained results were statistically analyzed and found to be in accordance with those given by the reported methods.

Using 9-Chloroacridine as A Chromogenic Reagent for The Detection of Tetracycline

A simple, sensitive, accurate and cost-effective method has been described for the quantitative determination of Tetracycline hydrochloride (TCs) in bulk drug and its pharmaceutical preparations in an aqueous medium. The proposed method is based on the nucleophilic substitution reaction of 9-chloroacridine (9-CA) as a chromogenic reagent with TCs in an aqueous solution forming a colored complex. The spectrum of the product shows maximum absorption at 385 nm against the blank. The linearity range of the calibration graph was (1-28) μg.mL-1 with a limited detection value (LOD) 0.138 μg.mL-1. The results show the absence of interferences from the excipients compounds on the determination of the drug. The suggested method exhibited high reproducibility (RSD) 2.3 % with mean percentage recovery (R%) 99.95. Furthermore, the stability constant has been calculated to be 9.843×105 L.mol-1 and the reaction mechanism is proposed. A ratio of 1: 1 was found between the above drug and the reagent using Job and molar ratio methods. The accuracy and validity of the proposed method were further determined by performing a recovery experiment by the use of the standard addition method. It is found that the method does not require extraction process and it agree well standard addition method. Appli

Separation and Determination of Diflunisal and its Impurity by Two Chromatographic Methods: TLC-Densitometry and HPLC.

Diflunisal (DIF) has analgesic and anti-inflammatory activity. It is a pharmacopeial drug found in the British Pharmacopoeia (BP), and its major pharmacopeial impurity is biphenyl-4-ol (BPL). DIF has not previously been determined together with BPL. The presence of BPL could significantly affect the dose of DIF in its dosage forms; hence it is crucial to determine DIF and BPL in each other's presence. TLC is the first proposed method, where DIF and BPL were separated on silica gel TLC F254 plates. The eluent was toluene-acetone-acetic acid solution (3.5:6.5:1, v/v). Reversed-phase (RP) HPLC is the second suggested method, where a mixture of DIF and BPL was separated on a C18 (5 µm ps, 250 mm and 4.6 id) column using phosphate buffer pH 4 (0.05 M)-acetonitrile (40:60, v/v). Detection was carried out at 254 nm in both methods. For the TLC method, concentration ranges of 0.5-3 and 0.3-1.7 µg/band were used, with mean percentage recoveries of 100.22% (SD 0.893) and 100.52% (SD 0.952) for DIF and BPL, respectively. The RP-HPLC method was carried out over a concentration range of 5-30 and 2-9 μg/mL, with mean percentage recoveries of 100.10% (SD 1.259) and 98.88% (SD 0.822) for DIF and BPL, respectively. The TLC and RP-HPLC methods were successfully applied for the determination of DIF and BPL, quantitatively, whether in bulk powder or in pharmaceutical formulations. Two chromatographic methods were developed and validated according to International Council on Harmonization guidelines for the assay of DIF and its pharmacopeial impurity.

Stability Indicating RP-HPLC Method Development and Validation for Estimation of Diroximel Fumarate in bulk and its dosage forms

Aim and objective: The aim of present research work is to develop validated RP-HPLC stability indicating method for the quantification of Diroximel Fumarate in bulk and its pharmaceutical dosage forms. Materials and methods: Chromatographic method was carried on C18 column (Waters 250mm x 4.6mm, 5m). Mobile phase was prepared by mixing water: Acetonitrile: 85% OPA: in the ratio of 70:30. The flow rate was 0.1 mL/min and the injection volume was 20μL. The absorbance maxima of Diroximel Fumarate was measured at 215nm. The retention time was found to be 2.390 min. Result: The method was proved to be specific and linear in the range of 50-150μg/mL with correlation coefficient of 0.999. The % RSD for precision was found to be less than 2% and the mean percentage recovery was 100.15%. All the validation parameters were statistically validated according to ICH guidelines and were found to be within acceptance criteria. Conclusion: The developed method was simple, specific, precise, accurate and robust. The described HPLC method can be successfully employed for the analysis of Diroximel Fumarate.

Simultaneous Estimation of Chlorpheniramine Maleate and Glyceryl Guaiacolate in Pure and Capsule Dosage form by using different Spectrophotometric Methods

Chlorpheniramine Maleate (CPM) and Glyceryl Guaiacolate (GUA) are the β‐lactum antibiotic drug. Sensitive, precise, accurate and simple, UV spectrophotometric methods have been developed for the simultaneous estimation of Chlorpheniramine Maleate (CPM) and Glyceryl Guaiacolate (GUA) in dosage form. Two spectrophotometric methods (simultaneoue equations and Q‐Absorbance ratio) were applied for the determination of the drugs as mixture. The maximum absorbance of drug in solvent mixture composed of water – acetontrile – methanol in a ratio of (80% H2O – 10% ACN – 10% MOH) was found to be at (261.4 nm and 273 nm) for CPM, GUA respectively, and the Q – isosbestic point was found at 270.4 nm. These wavelengths were selected for the analysis of drugs as mixtures standard and in the manufactured samples using the two developed methods. The methods were linear in the range of (1- 100) μg/mL for (CPM, GUA), with an R2 of (0.9996) for CPM and GUA respectively in the mixture. Recovery means were found to be (99.79 % - 100.30 %) for the standard drugs CPM and GUA respectively and in formulating drugs was found to be (99.71 – 100.41 %). LOD and LOQ were established and found to be (0.1 and 0.33) for CPM and GUA respectively. The method was applied for the estimation of the active gradient of the drugs in different samples of manufactured dosage. The accuracy of method was validated by mean percentage recovery, which was found to be in the acceptable range.

Comparison of extraction procedures for the determination of mesosulfuron methyl and iodosulfuron methyl sodium from soil and wheat using response surface modelling

Screening of herbicides is important due to their widespread use, phytotoxicity to succeeding crop and residues in soil and crop produce. For this development of simple, sensitive and cost effective analytical method for tracer level quantification of herbicides in different matrices is a challenging task. In present study, different extraction techniques viz. ultrasonic assisted extraction (UAE), matrix solid phase dispersion (MSPD), microwave assisted extraction (MAE) and liquid solid extraction (LSE) were compared for recovery and quantification of mesosulfuron methyl and iodosulfuron methyl sodium from soil and wheat samples by high performance liquid chromatography. Different factors affecting the extraction efficiency of the herbicides using these extraction methods were optimised. Response surface methodology (RSM) based on three factor and three level box behnken designs (BBD) were also employed to obtain a mathematical model representing the relationship between the response (percent recovery) and variables. The mean percent recoveries of herbicides varied from 89.80 to 101.20%, 89.20 to 99.75%, 81.10 to 90.75% and 83.40 to 94.75% using UAE, MSPD, MAE and LSE, respectively with RSD% <14% for all the four methods. The developed methods are reliable and can be useful for routine monitoring in soil and crop produce. The experimental results were extended to the analysis of real sample and residues in these were below the maximum residue limits (<0.01 mg kg−1) imposed by the principal regulatory agencies.

Development and Validation of a Effective and Reliable HPLC Method for the Quantification of Levodopa and Carbidopa in Pharmaceutical Formulations

A convenient and simple high performance liquid chromatography method for simultaneous separation, determination and identification of levodopa and carbidopa in pharmaceutical formulation has been developed. The analysis was carried out using Ace C18 (4.6 x 250 mm, 5 µm) column, and the separation was performed using a mobile phase consisting of 50 mM KH2PO4 (pH 2.3) pumped at a flow rate of 1.2 mL min-1 with UV detection at 280 nm. The method has been successfully validated on the basis of the International Conference on Harmonization (ICH) acceptance criteria. The method is selective, since no interferences corresponding to these analytes were found at retention times. Retention times for both drugs were 2.939 min and 5.018 for levodopa and carbidopa, respectively. The method was validated and shown to be linear in the concentration range of 25-125 µg mL-1 and 6.25-31.25 µg mL-1 for levodopa and carbidopa, respectively. The method exhibited good linearity (R2 &amp;gt; 0.999) over the assayed concentration range and showed good intra-day and inter-day precision. The limit of detection (LOD) and limit of quantification (LOQ) were determined based on standard deviation of the intercept and the slope of the calibration curve. LOD and LOQ values were 0.70 µg mL-1 and 2.13 µg mL-1 for levodopa and 1.31 µg mL-1 and 3.96 µg mL-1 for carbidopa, respectively. The method's accuracy was tested by adding known volume of standard solution (75 percent, 100 percent, and 125 percent concentration of the sample) to the 100 percent concentration pre-analyzed sample solution. The percentage mean recovery by standard addition experiments of levodopa and carbidopa is 99.75% and 99.55%, respectively. This method has also been successfully used for the determination of levodopa and carbidopa in pharmaceutical formulations.

An innovational validated spectrofluorimetric technique for determination of 6-Aminocaproic acid in pure form and its tablet: Application to spiked human plasma and urine

An innovative and sensitive spectrofluorimetric method has been developed for determination of 6-aminocaproic acid (ACA) in its pure form and its laboratory prepared tablets. The aim of this method is the reaction of ethyl acetoacetate and formaldehyde with the primary amino group presented in ACA as aimed in the Hantzsch reaction, this reaction resulted in formation of a yellow fluorescent dihydropyridine derivative that can be easily detected spectrofluorimetrically at 438 nm (excitation at 358 nm). At the optimum conditions of the reaction, the linear range was found to be (0.7–3.5 µg\\mL) with limit of detection is 0.231 µg\\mL and limit of quantitation is 0.700 µg\\mL. The proposed method used for detection of ACA laboratory prepared tablets with average percentage 100.721 ± 0.701% without any interference from any excipients. This method used for in vitro determination of ACA in spiked human plasma with a percent mean recovery 99.874 ± 1.416%. In addition, the developed method used for determination of ACA in spiked human urine with percent mean recovery 100.314 ± 1.793%.

A simple stability indicating RP-HPLC-DAD method for concurrent analysis of Tenofovir Disoproxil Fumarate, Doravirine and Lamivudine in pure blend and their combined film coated tablets

The main aim of the study was to develop an economical, insightful, accurate and simple RP-HPLC-DAD method with high precision and good sensitivity for concurrent determination of Tenofovir disoproxil fumarate, Doravirine and Lamivudine in blended bulk form and their combined tablet form. A method with Ascentis C18 (150×4.6mm, 5μm) column, mobile phase ratio of 0.1% ortho phosphoric acid and Acetonitrile in 70:30 (v/v), 1mL/min flow rate and detection wavelength of 260nm was highly proficient in effective separation of all three drugs. The developed method was validated in accordance with ICH specifications. The retention times of Doravirine, Lamivudine and Tenofovir disoproxil fumarate observed were 2.4, 2.9, and 3.6min, respectively. The linear responses were observed for Doravirine, Lamivudine and Tenofovir disoproxil fumarate in the range of 12.5-75μg/mL, 75-225μg/mL and 75-225μg/mL, respectively. The limit of detection and quantification values were calculated to be 0.36μg/mL and 0.11μg/mL for Lamivudine, 0.55μg/mL and 1.66μg/mL for Tenofovir disoproxil fumarate and 0.03μg/mL and 0.09μg/mL for Doravirine. The % RSD values of the intra-day and inter-day precision were calculated in the range of 0.134-1.749. The mean percentage recovery of all three analytes was in the range of 98.85-100.18%. The statistical results of the validation parameters ensured that the method was accurate, specific, and precise with good sensitivity. Investigation of analytes under different stressed conditions ensures the stability of analytes reflecting the stability indication of the method. The developed method has high proficiency in separation of Tenofovir disoproxil fumarate, Doravirine and Lamivudine. The degradation products generated due to stress conditions also separated with good resolution. The current method is a stability-indicating assay method consisting of appropriate specificity, accuracy, precision and sensitivity. The developed method has a good potential to be adopted by the pharmaceutical industrial sector.

Autologous Fibrin Glue Versus Microsuture in the Surgical Reconstruction of Peripheral Nerves: A Randomized Clinical Trial

This study compared the motor and sensory recovery and the operative time of autologous fibrin glue application with conventional microsuturing technique in repairing peripheral nerves at the forearm and wrist levels METHODS: Eighty-five patients with injuries of the median, ulnar, or both nerves at the wrist and forearm levels underwent nerve repair between September 2014 and June 2018. Patients were randomly assigned at the time of diagnosis to a microsuture group (42 patients), in which standard epineurial microsurgical suturing was performed, or a fibrin glue group (43 patients), in which nerve repair was performed using autologous fibrin glue. The primary outcome measure was motor and sensory recovery. Operative time was the secondary outcome measure. Other outcome measures that were added post hoc, after trial initiation, included time to motor and sensory recovery; grip strength; pinch strength; Michigan hand outcome score; amplitude, latency, and duration of the compound motor unit action potential; and complications. All patients were followed up a minimum of 1 year. At the final follow-up, both groups had regained similar motor and sensory function. The mean operative time was shorter in the fibrin glue group. Both groups had similar amplitude, latency, and duration of the compound motor unit action potential. Michigan Hand Outcome scores and mean percent recovery of grip strength and pinch strength were also similar. Six of 43 patients in the fibrin glue group compared with 8 of 42 patients in the microsuture group developed postoperative complications. The use of fibrin glue to repair peripheral nerves is as effective as microsuturing in regaining motor and sensory functions and is associated with shorter operative time. Therapeutic II.

ANALYTICAL METHOD DEVELOPMENT AND VALIDATION OF GEMCITABINE AND CLARITHROMYCIN IN COMBINED DOSAGE FORM BY RP-HPLC METHOD

A reverse phase high performance liquid chromatographic method was developed for simultaneous estimation of gemcitabine and clarithromycin in bulk and tablet dosage form. The method was developed by using acetonitrile: methanol: 50 mM sodium acetate buffer (adjusted to pH-3 with orthophosphoric acid (40:40:20) as a mobile phase at the flow rate of 1mL/min. The retention time was found to be 2.365 and 5.999 minutes, respectively. The method showed linearity in the concentration range 10-50 µg/mL in respect of both drugs. The % RSD was less than 0.4% for gemcitabine and 0.2% for clarithromycin. Mean percentage recovery was found to be 99.63 and 99.69 for gemcitabine and clarithromycin. The tailing factor for gemcitabine and clarithromycin was not less than 0.9 and not more than 1.4 during the robustness study. The average percentage assay was calculated and found to be 99.83 for gemcitabine and 98.89 for charithromycin. The limit of detection and quantification for gemcitabine was found to be 0.41 and 1.79 µg/mL. For Clarithromycin, the value was 0.58 and 1.37 µg/mL respectively.

Simultaneous determination of ezetimibe, atorvastatin and simvastatin using quadrupole LC-MS: Application to combined tablets and plasma after SPE

AbstractA simple and sensitive liquid chromatography-mass spectrometric (LC-MS) method has been developed and validated for the simultaneous determination of ezetimibe (EZE), atorvastatin calcium (ATO), and simvastatin (SMV) in combined dosage forms and human plasma. Successful separation of the studied drugs was achieved on a Zorbax Eclipse Plus C18 column (3.0 × 150 mm, 5 µm) using a mobile phase consisting of acetonitrile and 0.1% formic acid in water (65:35, v/v) at a flow rate of 0.5 mL min−1. Total run time was 9.3 min and diclofenac sodium was used as internal standard (IS). Positive selected ion monitoring (SIM) mode was applied where, the monitored ions were those at m/z values of 392.1, 559.3, 296.0, and 441.4 corresponding to EZE, ATO, IS, and SMV, respectively. The method was fully validated according to the ICH guidelines. The intraday and interday precision showed relative SD values not more than 1.77 and 1.99%; respectively. The limits of detection (LOD) were 0.25, 0.25, and 0.75 ng mL−1 while the limits of quantification (LOQ) were 1.25, 0.75, and 2.5 ng mL−1 for EZE, ATO, and SMV, respectively. The developed method was applied on two types of combined tablets concerning drug assay with mean percent recoveries within acceptable range. The method has been extended to the determination of the studied drugs in human plasma where, a solid phase extraction method was optimized for their extraction with percent recovery not less than 97%.

Development and validation of a stability indicating RP-HPLC-DAD method for the determination of bromazepam.

A reliable, selective and sensitive stability-indicating RP-HPLC assay was established for the quantitation of bromazepam (BMZ) and one of the degradant and stated potential impurities; 2-(2-amino-5-bromobenzoyl) pyridine (ABP). The assay was accomplished on a C18 column (250 mm × 4.6 mm i.d., 5 μm particle size), and utilizing methanol-water (70: 30, v/v) as the mobile phase, at a flow rate of 1.0 ml min-1. HPLC detection of elute was obtained by a photodiode array detector (DAD) which was set at 230 nm. ICH guidelines were adhered for validation of proposed method regarding specificity, sensitivity, precision, linearity, accuracy, system suitability and robustness. Calibration curves of BMZ and ABP were created in the range of 1–16 μg mL-1 with mean recovery percentage of 100.02 ± 1.245 and 99.74 ± 1.124, and detection limit of 0.20 μg mL-1 and 0.24 μg mL-1 respectively. BMZ stability was inspected under various ICH forced degradation conditions and it was found to be easily degraded in acidic and alkaline conditions. The results revealed the suitability of the described methodology for the quantitation of the impurity (ABP) in a BMZ pure sample. The determination of BMZ in pharmaceutical dosage forms was conducted with the described method and showed mean percentage recovery of 99.39 ± 1.401 and 98.72 ± 1.795 (n = 6), respectively. When comparing the described procedure to a reference HPLC method statistically, no significant differences between the two methods in regard to both accuracy and precision were found.

Chemometric spectrophotometric methods for simultaneous estimation of metoprolol succinate and amlodipine besylate in their tablet formulation

Two simple chemometric spectrophotometric methods; isosbestic point and dual wavelength methods were developed, validated and applied to the determination of metoprolol succinate in presence of amlodipine besylate in their binary mixtures and in combined tablet formulation while amlodipine besylate was determined by direct spectrophotometry at λ = 365 nm within linearity range of 2–25 μg/mL. The mean percentage recovery ± SD was 99.921 ± 0.089 for amlodipine besylate. Two proposed chemometric spectrophotometric methods were developed for the spectral resolution of metoprolol succinate in presence of amlodipine besylate without preliminary separation with a linearity range of 2–30 μg/mL metoprolol succinate. The first method depended on measuring the absorbance at the isosbestic point at λ = 226 nm. The mean percentage recovery ± SD was 100.110 ± 0.249 for metoprolol succinate. The second method was dual wavelength method, metoprolol could be determined alone using the absorbance difference between 226 nm and 248.7 nm where the absorbance difference was zero for amlodipine at these two wavelengths. The mean percentage recovery ± SD was 99.734 ± 0.438 for metoprolol succinate using dual wavelength method. The developed methods were validated as per ICH guidelines and were successfully applied to analysis of cited drugs in their synthetic tablet formulation. The results obtained by the developed methods were statistically compared to those obtained by a reported one using t-test and F- test. Good agreement was observed.