Drugs In Pharmaceutical Preparations Research Articles

Spectrophotometric Assessment of Pyrocatechol Drug Employing Oxidative Coupling Reaction with 4-amino antipyrine as a Model of Pharmaceutical Compounds .

A rapid, simple, sensitive, and higher stability spectrophotometric method was developed the determine that it is stable Pyrocatechol drug in pure and pharmaceutical preparations. The method is based on an oxidative coupling reaction among Pyrocatechol drug and 4-amino antipyrine (4AAP) in the presence of potassium iodate (KIO3) in an acid medium to form a color complex that stable violet dye and a maximum absorption at 505 nm. The best optimum conditions and other analytical factors have been evaluated. A calibration curve of absorbance of several concentrations that obey the law of Beer-Lambert over the range concentration of pyrocatechol drug 10 to 100 mg/L, with (LoD =1.2*10-4 mg/L), (LoQ=3.4*10-4 mg/L), The relative standard deviations RSD% of the proposed methods were less than 0.68%). In contrast, recovery average and determination parameters are 99.9%. The method was used successfully for the determination of drugs in a pharmaceutical preparation with the best accuracy and precision. At range about 99.1 to 100.2% with RSD less than 0.3%. The analytical result for the estimation of the pure drug is presented together with the use of the proposed process for the analysis of some commercial pharmaceuticals. The data compare favorably with those of official and reported ways.

A Spectrophotometric Determination of Amlodipine Drug in Pharmaceutical Preparations Using 2, 6-Dihydroxybenzoic Acid Reagent

In this study, a delicate, exact, and efficient colorimetric spectrophotometric technique was created for the assessment of Amlodipine in its unadulterated structure and in drug arrangements The strategy depends on the response of the optional amine in the medication with the carbonyl gathering in the natural reagent 2, 6 dihydroxy benzoic corrosive within the sight of p-dimethyl amino benzaldehyde to frame a yellow complex (Manich complex). The greatest absorbance was viewed as at 402 nm. Linearity was seen in the scope of 2-40 μg/mL, and the connection coefficient was viewed as 0.9909. The molar absorptivity was viewed as 1.392 × 104 L•mol-1•cm-1. It was observed that the shade of the item was steady and no massive change in absorbance was noticed for as long as 50 minutes a recuperation of 100.596% was gotten. The restriction of discovery (LOD) and cutoff of evaluation (LOQ) were viewed as 0.968 µg/mL and 3.228 µg/mL, individually. The %RSD was 4.32, which demonstrates the precision of the proposed strategy.

Furosemide Determination in Pharmaceutical Samples Using Differential Pulse Polarographic method

The research includes the development of a simple, sensitive and accurate differential pulse polarography method for the quantitative determination of furosemide drugs in pharmaceutical preparations and in their pure and commercial forms, the electrochemical behavior using the dropping mercury electrode DME, as well as finding the values of the half-wave potential (E1/2) as a qualitative value, the number of electrons that were transferred and participating in the reduction process. The furosemide drug showed a clear reduction peak at a voltage of (-0.24) volts under optimal conditions. The correlation coefficient for furosemide at a concentration range of (2–24) µg.ml-1 was 0.9969, the LOD and LOQ of the drug were 2.139 and 7.129, respectively, and the average relative standard deviation (RSD) of the drug was 1.41%, with recovery of the f drug 97.58% and (n =5).

Spectrophotometric Method for the Determination of Catechol Amines Drugs in Pharmaceutical Preparations

Spectrophotometric methods were developed for the estimation of diazotization of metoclopramide hydrochloride and coupling with catecholamine (dopamine and adrenaline) at the same order. The resulting a violet color that appear to have maximum absorption at λmax 566 nm, and λmax (561) adrenaline, and dopamine, respectively. The optimum conditions of the experiment were individually performed to fi nd high absorbance effi ciency for both drugs. Under the best conditions, law Beer’s lambert was obeyed in the concentration of two drugs range of 1–20 mg/L (R2 = 0.9984), (R2 = 0.9965), and lead to obtain the limit of quantitation (LoQ) (μg mL-1) 0.155 and 0.138, and limit of detection (LoD) (μg mL-1) 0.517 and 0.461, adrenaline, dopamine at the same order. The proposed process was applied and validated to estimate adrenaline and dopamine in several samples of pharmaceutical preparations.

Carbon Paste Modified with Peony‐Like CuO : Tb3+Nanostructures for the Simultaneous Determination of Sumatriptan and Naproxen in Biological and Pharmaceutical Samples

AbstractThis work studied a new carbon paste electrode modified with peony‐like CuO : Tb3+nanostructure (P−L CuO : Tb3+NS/CPE) for electrochemical detection of sumatriptan and naproxen using cyclic voltammetry, chronoamperometry and differential pulse voltammetry. Based on the findings, there was an improvement in the voltammetric behavior of sumatriptan and naproxen on the P−L CuO : Tb3+NS/CPE surface when comparing with the bare CPE. The correlation of oxidation currents with the pH value, concentration and sweep rate of supporting electrolyte were determined for the optimization of conditions to detect the sumatriptan and naproxen. The surfaces of modified and unmodified electrodes were characterized as well. The diffusion‐control processes were confirmed on the basis of anodic peak findings. The results also revealed a two‐electron transfer process. The sumatriptan and naproxen were co‐detected via the modified electrode, with a range of 0.01‐800 μM and 0.01–700 μM respectively, and a detection limit of 3.3 nM and 2.7 nM, sequentially. An accuracy was found by the differential pulse voltammetry for co‐detection of these two drugs in pharmaceutical preparations and pathological specimens. In conclusion, we suggest the proposed approach for electrical determinations in the management of environmental contamination and industrial quality because of its unique properties like facile sample preparation, and appreciable sensitivity, repeatability and reproducibility.

Electroanalytical methods for determination of antiviral drugs in pharmaceutical formulation and biological fluids: A review

• In this review, electroanalytical methods developed for the determination of antiviral drugs have been compiled. • The theory of the developed methods is given briefly. • The operating conditions of all reported methods are summarized. • The application area and sensitivities of the method are reported. Viruses can infect all kinds of life forms, from humans, animals and plants to microorganisms, including bacteria and archaea, and can cause serious illness, including a pandemic. Antivirals act as a blocking mechanism against the viral replication cycle at various stages to treat viral infections. Currently, antiviral therapy is available for a limited number of infections and is mainly used to minimize symptoms, further spread, and shorten the duration of the illness. For this reason, it is very important to develop fast, precise and reliable methods to analyze antiviral drugs from dosage forms or biological samples. Electroanalytical methods have been used frequently in the analysis of antiviral drugs comprising of different structures. Electrochemical methods have an important place among analytical methods with their unique features such as specificity, high sensitivity, reliability, economical, easy sample preparation, and no pre-analysis process. The purpose of this review article is to compile published electrochemical methods for the determination of antiviral drugs in pharmaceutical preparations and biological fluids. In addition to these applied methods, the types of electrodes used, and the materials used in the modification and designation of these electrodes are classified and briefly explained with their limitations. Published all electrochemical methods for the determination of antiviral drugs in pharmaceutical preparations and biological fluids have been compiled so far. Detailed application conditions, electrodes with their materials are classified and explained with their limitations.

Review on Characterization, Properties, and Analytical Methods of Cefepime.

Infection is one of the most important reasons for the increase in the number of deaths worldwide; it can be a bacterial or viral infection. As a result, there are many effective drugs against this infection, especially bacterial ones. Cefepime (CP) is one of the fourth generations of cephalosporins and is distinguished from others in that it can kill both positive and negative bacteria. Therefore, this study focused on the chemical properties of the drug, its uses, and its stability against bacteria. All analysis methods for this drug in pharmaceutical preparations, blood, or plasma were also presented. One of the important problems in these methods is using toxic solvents, which poses a danger to society and the environment. The presentation of these solvents will allow companies to manufacture and use more effective and less toxic solvents.

Stability-indicating HPLC method development and validation for simultaneous estimation of metformin, dapagliflozin, and saxagliptin in bulk drug and pharmaceutical dosage form.

A simple, precise, and rapid stability-indicating reversed-phase-HPLC method was developed and validated for the estimation of metformin (MET), dapagliflozin (DAP), and saxagliptin (SAX) combination in bulk and tablet dosage forms. The proposed method uses a Kromasil C18 column (150 × 4.6mm, 5μm) with column oven temperature of 30°C and mobile phase containing a mixture of 60% phosphate buffer (pH = 3) and 40% acetonitrile. The flow rate was set at 1.0mL/min, and the injection volume was 10μL. The detection was carried out at 230 nm using a photodiode array detector, and the total run time was 4min. The proposed method was validated according to International Council for Harmonisation (ICH) guidelines for specificity, linearity, precision, accuracy, robustness, and solution stability. The method is linear over the range of 125-750 μg/mL for MET, 1.25-7.5μg/mL for DAP, and 0.625-3.75 μg/mL for SAX. The observed correlation coefficients (R2 ) for MET, DAP, and SAX are >0.999. The proposed method is precise, and the percentage relative standard deviation was found to be between 0.4 and 0.8. The observed percentage recoveries were between 98.51 and 100.80 for all three compounds. The product was subjected to stress conditions of acid, base, oxidative, thermal, and photolytic degradation. The product was found to degrade significantly in oxidative, acid, and base hydrolysis degradation conditions, and the degradation products were well determined from the active peaks, thus proving the stability-indicating power of the method. The developed and validated stability-indicating reversed-phase-HPLC method was appropriate for quantitative determination of these drugs in pharmaceutical preparations and also for quality control in bulk manufacturing.

Stability-indicating RP-HPLC assay of three novel oral anticoagulants binary mixtures with rosuvastatin calcium: Application to pharmaceutical preparations and human plasma

The binary mixtures of the novel oral anticoagulants (NOACs); Apixaban (APX), Edoxaban tosylate (EDX) and Rivaroxaban (RIV) with the lipid lowering statin; Rosuvastatin calcium were analyzed using a validated HPLC-DAD method. This method was suitable for the quantitative assay of the targeted mixtures in tablets and human plasma. The analysis in dosage form was a stability indicating one where the drugs were separated from possible degradation products arising from applying different stress conditions. For analysis in human plasma, EDX was used as internal standard in APX/ROS and RIV/ROS mixtures, while APX was used as internal standard in EDX/ROS mixture and the method was validated according to FDA regulation for analysis in biological fluids. A ZORBAX Eclipse column C18 (4.6 × 150 mm × 5 µm) was used as stationary phase with a gradient eluting mobile phase composed of acidified water and acetonitrile. The method selectivity was demonstrated by its ability to simultaneously analyze the drugs in presence of possible forced degradation products and dosage form excipients and in presence of plasma interferences (analysis in biological fluid) at a single wavelength (291 nm) with the use of the internal standard. The simplicity of the method emphasizes its capability to analyze the drugs in pharmaceutical preparations and human plasma. This is very important in regular clinical monitoring of the drugs plasma concentrations for cardiovascular patients medicated with either of these combinations, as prophylaxis from stroke, in order to prevent severe bleeding and to achieve optimum dose adjustment.

Comparative Determination of Chlorpromazine in Pharmaceutical Injectable Veterinary and Human Formulations by Spectrophotometric and High Performance Liquid Chromatographic Methods

Background: Chlorpromazine (CPZ) is a phenothiazine tranquilizer used in humans and animals. Rapid determinationof the drug in pharmaceutical preparations is often needed. The aim of the study was to further examine and ascertainasimple spectrophotometric method in comparison with a high performance liquid chromatographic (HPLC) methodfor the determination of CPZ concentrations in injectable pharmaceutical formulations used in man and animals.Methods: Concentrations of CPZ in injectable pharmaceutical formulations for human and veterinary uses weredetermined by a modified spectrophotometric method and by an HPLC method with appropriate standard calibrationcurves. The spectrophotometric method of CPZ determinationwas conducted by diluting 0.1 ml of the veterinary(5%) or 0.3 ml of human (0.5%) formulations to 200 ml of 0.1N sulfuric acid. Four ml of the diluted CPZ samples orthe standard solutions were mixed with 2 ml of 50% sulfuric acid. Then an aliquot of 0.2 ml of 2% ferric nitrate wasadded to the mixture. After 15 minutes, the absorbance was measured at 530 nm against water and vehicle blanksusing a spectrophotometer. The HPLC method applied in the present study consisted of reversed phase gradientchromatography with a C18 column and the eluent was (A) 50 mmol NaH2PO4, pH 2.5 and (B) acetonitrile - 50mmol NaH2PO4, pH 2.5 (60:40 v/v), flow rate at 1 ml/min, with a gradient of 15-55% B in 10 min, to 100% B in20 min, and 280-nm UV detection. From the calibration curves of CPZ standards, the following were calculated:Limit of detection limit (LOD) = 3.3 x SD/slope; Limit of quantitation (LOQ) = 10 x SD/slope, where SD is thestandard deviation of response of CPZ concentrations of the calibration curves.Linear regression analysis and relatedcoefficients of correlations were applied on the calibration curves. Results: The calibration curves of CPZ againstwater or vehicle blanks as determined by the spectrophotometric method or by the HPLC method were linear withstrong correlations (r = and / or >0.99). Based on the calibration curves, limit of detection and limit of quantitation thespectrophotometric method were comparable to those of the HPLC one. The contents CPZ in human and veterinaryinjectable formulations as determined by the spectrophotometricmethod were in accordance (100.6% and 102%,respectively)to the concentrations claimed on the labels of the formulations.Conclusion: The present results introduce a simple spectrophotometric method that could be used for routinemeasurement of CPZ concentrations in pharmaceutical formulations, with the added benefits of linearity, precisionand cost effectiveness.

Method Development and Validation for Estimation of TinofovirDisproxil Fumarate in Pharmaceutical Preparation by UV-Spectroscopy and HPLC With Force Degradation Study

Tinofovir Disoproxil Fumarate (TDF) is an acyclic nucleotide diester analog of adenosine monophosphate from the antiviral category utilized in the AIDS and hepatitis B treatment. In the present study, two analytical methods, i.e. UV and HPLC were developed for the TDF’s estimation in pharmaceutical preparation. In the UV method, the mobile phase used was Methanol and water in 60:40 ratio for estimation of the drug at 260 nm and an assay of the (TDF) obtained was 99.53%. The method’s validation was carried out as per ICH Q2 R1 guidelines in which linearity was detected from 10-50 µg/ml range with a regression value of 0.999 Percent RSD value of accuracy, precision and robustness were below 2. In the HPLC method estimation of (TDF) was evaluated on Cosmosil C-18 (250mm×4.6ID, Particle size: 5 µ) column utilizing Methanol: Water (60:40), 0.9 ml/min of flow rate, detection wavelength was 260 nm and the time of retention observed was around 4.63 minutes with the assay value 99.07%. HPLC method was also validated according to ICH guidelines, where linearity was detected in the 10-50 μg/ml of range with the regression coefficient value 0.999. The % RSD of precision, accuracy, and robustness was below 2%. The study of forced degradation was also performed by the HPLC method utilizing methanol: water (60:40) at 260nm. From this study, it can be concluded that the developed methods for estimation of (TDF) drug in pharmaceutical preparation are simple, accurate, precise, and can be utilized in the routine analysis for quantification of the drug in a dosage form.

Simultaneous enantioseparation and simulation studies of atenolol, metoprolol and propranolol on Chiralpak® IG column using supercritical fluid chromatography

Enantioseparation of three β-blockers, i.e., atenolol, metoprolol and propranolol, was studied on amylose tris(3-chloro-5-methylphenylcarbamate) immobilized chiral stationary phase using supercritical fluid chromatography (SFC). The effect of organic modifiers (methanol, isopropanol and their mixture), column temperature and back pressure on chiral separation of β-blockers was evaluated. Optimum chromatographic separation with respect to resolution, retention, and analysis time was achieved using a mixture of CO2 and 0.1% isopropyl amine in isopropanol: methanol (50:50, V/V), in 75:25 (V/V) ratio. Under the optimized conditions, the resolution factors (Rs) and separation factors (α) were greater than 3.0 and 1.5, respectively. Further, with increase in temperature (25–45 °C) and pressure (100–150 bars) there was corresponding decrease in retention factors (k), α and Rs. However, a reverse trend (α and Rs) was observed for atenolol with increase in temperature. The thermodynamic data from van't Hoff plots revealed that the enantioseparation was enthalpy driven for metoprolol and propranolol while entropy driven for atenolol. To understand the mechanism of chiral recognition and the elution behavior of the enantiomers, molecular docking studies were performed. The binding energies obtained from simulation studies were in good agreement with the elution order found experimentally and also with the free energy values. The method was validated in the concentration range of 0.5–10 μg/mL for all the enantiomers. The limit of detection and limit of quantitation ranged from 0.126 to 0.137 μg/mL and 0.376–0.414 μg/mL, respectively. The method was used successfully to analyze these drugs in pharmaceutical preparations.

Successful spectrofluorometric and chemiluminescence methods for the estimation of azathioprine as an immunosuppressive drug in pharmaceutical preparation

The determination of azathioprine (AZA), a mercaptopurine derivative, has attracted a particular attention in most researches. Herein, spectrofluorometric (I) and chemiluminescence (II) methods were successfully confirmed to estimate azathioprine (AZA) in bulk powder form and pharmaceutical preparation. The optimum conditions to improve the fluorescence and chemiluminescence intensity of AZA were investigated. The method (I) measured the native fluorescence intensity of AZA in methanol as solvent, without any addition. The micelle-enhanced fluorescence of AZA was affected by the surfactant addition, type of solvent, pH value, and the volume of sodium dodecyl sulfate (SDS). The method (II) consisted in the improvement of the weak signal of calcein–KMnO4 chemiluminescence system by introducing synthesized silver nanoparticles (AgNPs) in the presence of AZA. The analytical curves were linear in the concentrations range 5.0 × 10−8 − 1.0 × 10−4 M and 5.0 × 10−9 − 2.0 × 10−3 M with a detection limit equal to 1.5 × 10−9 M and 2.6 × 10 −10 M for techniques (I) and (II), respectively. The statistical analysis indicated no significant difference between the proposed and reported methods. The suggested techniques were successfully used to determine azathioprine in its tablet form and were validated according to ICH guidelines.

New and validated RP-HPLC Method for Quantification of Safinamide Mesylate in Presence of Its Basic Degradate, Levodopa and Ondansetron: Application to Human Plasma.

A simple, precise, rapid and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for analysis of safinamide mesylate (SAF) in presence of its basic degradate, and co-administered drugs levodopa and ondansetron. The mobile phase consisted of acetonitrile and 20 mM potassium dihyrogen orthophosphate buffer having pH=5 (40: 60v/v). Quantification was achieved with ultraviolet detector at 226nm. The linear range was 0.5-10μg/mL with mean recovery ± SD of 99.72±1.59. The peak purity of SAF in pharmaceutical preparation spiked with its degradate and co-administered drugs revealed symmetry factor (999.8) within the calculated threshold (>998.1). The suggested method was validated in compliance with the International Conference on Harmonization (ICH) guidelines and statistically compared with the manufacturer HPLC method with no significant difference in terms of accuracy and precision. The assay method was successfully used to estimate SAF in tablets with good percentage recoveries. The high sensitivity (lower than Cmax of the drug 0.65μg/mL) of the proposed HPLC method enabled the determination of SAF in presence of its basic degradate and co-administered drug, ondansetron in human plasma with acceptable accuracy. The suggested HPLC method could be used in Quality Control (QC) lab for analysis of the studied drug in pharmaceutical preparation.

Development and Validation of a Novel Stability-Indicating RP-HPLC Method for Simultaneous Determination of Tezacaftor and Ivacaftor in Fixed Dose Combination.

A simple and precise novel stability-indicating method for the simultaneous estimation of tezacaftor and ivacaftor in combined tablet dosage form was developed and validated using reversed-phase high-performance liquid chromatography (RP-HPLC). The method is being reported for the first time and includes an estimation of degradation products produced post-stress conditions without any extraction or derivatization. The chromatographic separation of the drugs was achieved with a Symmetry Shield RP18 Column (100Å, 5μm, 4.6mm × 250mm) using a mixture of buffer, methanol and acetonitrile (42:27:31v/v/v) as mobile phase. The buffer used in mobile phase contained 35mM potassium dihydrogen phosphate, and its pH was adjusted to 7.0±0.02 with 20% orthophosphoric acid. The instrument was set at flow rate of 1.2 mL min-1 at ambient temperature and the wavelength of UV-visible detector at 275nm. The developed method could be suitable for the quantitative determination of these drugs in pharmaceutical preparations and also for quality control in bulk manufacturing. Stress testing was performed to prove the specificity. No interference was observed from its stress degradation products. The statistical analysis was done by using F-test and t-test at 95% confidence level.

Simultaneous Capillary Liquid Chromatography Determination of Drugs in Pharmaceutical Preparations Using Tunable Platforms of Polymethacrylate Monolithic Columns Modified with Octadecylamine

Nowadays, analytical techniques tend to develop cheap and green approaches to reduce the costs and minimize environmental impacts. In this study, poly(glycidyl methacrylate-co-ethylene dimethacrylate) monoliths were prepared in capillary columns (0.25 mm i.d. × 20 cm length) as reactive and tunable platforms, and then simply functionalized based on a ring-opening reaction of epoxide with octadecylamine. The columns were successfully used as reversed-phase stationary phases for determination of ascorbic acid, paracetamol, caffeine, aspirin, and ibuprofen in pharmaceutical combinations. The synthesized monoliths have been estimated by FT-IR spectroscopy, SEM and specific surface area; also, the porous and hydrodynamic properties have verified the differences before and after modification. While the columns before modification were unable to separate the drugs, the columns after amination allowed for the complete separation of the five drugs in about 10 min at 23 µL min−1 flow rate with chromatographic resolution more than 2.12. The developed assay showed excellent suitability (RSDs < 2.6%), wide linear ranges (0.07–300 µg mL−1), sensitive detection limits (0.022–0.060 µg mL−1), good repeatability (RSDs < 4.76%) and acceptable columns reproducibility (RSDs < 18.58%). The method was successfully applied for commercial pharmaceutical preparations; the average recovery values were found to be in the range of 98.03–104.54% (RSDs < 5.51%). The satisfactory recovery percentages along with the perfect correlation between the retentions of standard compounds and the active ingredients extracted from the commercial tablets indicate the accuracy and selectivity of the developed method. The prepared columns and validated method were finally compared with previous reports, particularly commercial C18 stationary phases. This is a very useful comparison due to the structural similarity between the prepared polymeric materials and C18 particulate stationary phases. The prepared capillary columns exhibited various advantages such as the fast separation time, wide linear ranges, low analysis costs, and trivial environmental wastes.

INTERNATIONAL CONFERENCE ON HARMONIZATION RECOMMENDED FORCED DEGRADATION STUDIES AND DEVELOPMENT OF A NEW VALIDATED ISOCRATIC REVERSE-PHASE ULTRA HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE SIMULTANEOUS ESTIMATION OF TELMISARTAN AND AMLODIPINE I

Objective: The objective of this research work is to develop a simple, rapid, cost-effective, accurate, precise, and robust stability-indicating reversephase ultra-high performance liquid chromatography method for the quantitative estimation of telmisartan (TEL) and amlodipine (AMD) in combined tablet dosage form.&#x0D; Methods: The method uses Poroshell 120EC-C18 column (4.6 mm × 50 mm, 2.7 μm) with an optimized mobile phase containing acetonitrile:50 mM ammonium acetate buffer in the ratio (45:55 v/v), pH adjusted to 4.5 with acetic acid. The flow rate was 0.5 ml/min, column temperature at 25°C and detection was monitored by a PDA detector at a wavelength of 245 nm. International Conference on Harmonization (ICH) recommended stress degradation studies were performed on TEL, AMD standard drugs, and tablet formulations; further stressed samples were analyzed by the proposed method.&#x0D; Results: Major degradation of TEL and AMD was observed under acidic, alkali, hydrolytic and oxidation conditions. The described method was validated as per the ICH guideline and validation parameters such as system suitability, linearity, accuracy, precision, specificity, and robustness results were within acceptable limits.&#x0D; Conclusion: The method was found to be suitable and accurate for quantitative estimation and stability study of title drugs in pharmaceutical preparations.

ANALYTICAL METHODS FOR THE QUANTITATION OF AMLODIPINE BESYLATE AND ATORVASTATIN CALCIUM IN PHARMACEUTICAL DOSAGE FORM AND BIOLOGICAL FLUIDS

Amlodipine is the best-prescribed medication for cardiovascular disease major risk factor for hypertension and atorvastatin well known for diabetic. First discussed low cost ultraviolet-visible technique for the determination and quantitation of drugs in pharmaceuticals and biological fluids. Chromatographic techniques have an application with respect to trace analysis. Different types of chromatography such as high-performance liquid chromatography, high performance thin layer chromatography have most frequent applications in the field of pharmaceutical as well as biomedical analyses. Chromatography combined with mass spectrophotometry has the ability to collect molecular ion, followed to prepare a spectrum to assess molecular weight as well as structure. High-performance liquid chromatography coupled with mass spectrophotometry is a reliable and dynamic technique for the analysis of small and large drugs molecule. The advantages and disadvantages of all techniques are compared with each other with respect to sensitivity, reproducibility and other important parameters. The investigation also focused for the quantitation on both drugs in pharmaceutical preparations and plasma samples with the help of all available analytical techniques.

Determination of Atomoxetine Hydrochloride in Biological Fluids Using Potentiometric Carbon Paste Electrode Modified by TiO2 Nanoparticles

Endeavors to improve the limit of detection for atomoxetine-selective electrode were documented. Simple potentiometric carbon paste electrodes (CPEs) based on atomoxetine-derivatized with tetraphenylborate (ATM-TPB) or phosphotungstic acid (ATM-PTA) as ion-pairs decorated with TiO2 nanoparticles and sodium tetraphenylborate (Na-TPB) as additives were most useful. Parameters affecting the performance of the electrodes were investigated, such as paste composition, type of plasticizers, kind of electroactive materials and interfering species. The electrodes were notable for bringing down the detection limit to 8.0 x 10-7 M and 9.2 x 10-7 M, wide linear ranges 1.1 x 10-6-1.0 x 10-2 M and 1.75×10-6-1.00×10-2 M, slope 58.7±0.5 mV/decade and 67.2±0.8 mV/decade, respectively. Importantly, the potential reading became more stable and rapidly attained in the presence of additives. The selectivity for the drug over other species such as inorganic and organic cations, as well as different excipients that are likely incorporated in pharmaceutical preparations was high making their effect negligible on the response of the electrodes. The sensors, as indicator electrodes, were successfully applied for determination of the drug in pharmaceutical preparation, urine and serum with good accuracy, excellent recovery and efficiency.

Simultaneous determination of methocarbamol and aspirin in presence of their pharmacopeial-related substances in combined tablets using novel HPLC-DAD method

Objective and Significance: Methocarbamol (MET) and aspirin (ASP) are widely used as a muscle relaxant combination. The USP reports guaifenesin (GUA) and salicylic acid (SAL) as related substances and hydrolytic products of MET and ASP, respectively. This work aimed at developing and validating a simple and sensitive RP-HPLC method for the determination of both drugs as well as their related substances (at their pharmacopeial limits) in their bulk powders, laboratory prepared mixtures, and MET-ASP combined tablets. Methods and Results: Chromatographic separation was achieved in less than 9 min with the required resolution, peak symmetry, and accuracy on C18 column using isocratic elution system of diluted acetic acid (pH 3.2): acetonitrile at the ratio of 79: 21, v/v, at a flow rate of 1 mL/min. Detection was achieved with photodiode array at 233 nm for MET, GUA, and SAL and at 273 nm for ASP. The developed method has been validated as per ICH guidelines and the calibration plots were linear over the concentration ranges of 2–150, 0.4–30, 25–450, and 0.2–27 μg/mL for MET, GUA, ASP, and SAL, respectively. Conclusion: The optimized method proved to be specific, robust and precise for the quality control of the studied drugs in pharmaceutical preparations to ascertain that their related substances are not exceeding the permitted pharmacopeial limits.