Flow Injection Spectrophotometric Methods Research Articles

Indirect Flow Injection Spectrophotometric and Chromatographic Methods for the Determination of Mebendazole in Pharmaceutical Formulations

Chromatographic and spectrophotometric methods for the estimation of mebendazole in pharmaceutical products were developed. The flow injection method was based on the oxidation of mebendazole by a known excess of sodium hypochlorite at pH=9.5. The excess sodium hypochlorite is then reacted with chloranilic acid (CAA) to bleach out its color. The absorbance of the excess CAA was recorded at 530 nm. The method is fast, simple, selective, and sensitive. The chromatographic method was carried out on a Varian C18 column. The mobile phase was a mixture of acetonitrile (ACN), methanol (MeOH), water and triethylamine (TEA), (56% ACN, 20% MeOH, 23.5% H2O, 0.5% TEA, v/v), adjusted to pH = 3.0 with 1.0 M hydrochloric acid. Naphazoline nitrate was used as an internal standard. The absorption of mebendazole was measured using a variable wavelength UV detector at 290 nm. Linearity was obtained in the concentration range of 1-60 and 0.10-3.0 mg/L for the HPLC and FIA, respectively. The methods were applied successfully for the assay of mebendazole in pharmaceutical products and no interferences were observed from the common excipients usually used. The proposed methods were validated for their accuracy and precision.

طرق القياس الطيفي للحقن الدفعي والتدفق لتقدير السيفتازيديم في التركيبات الصيدلانية

تم وصف تقنيتين طيفيتين لقياس كمية السيفتازيديم (CFT) في الأدوية والتركيبات الصيدلانية. فهي بسيطة وحساسة وانتقائية ودقيقة وفعالة. يستخدم الأسلوب الأول وسيطًا قلويًا لتحويل السيفتازيديم إلى ملح الديازونيوم ، والذي يتم دمجه بعد ذلك مع كواشف1-Naphthol (1-NPT) و2)2-Naphthol-NPT). تم إنتاج صبغة الآزو باللونين البني والأحمر ، مع كثافة امتصاص تصل إلى ƛmax 585nm and max 545nm ، على التوالي. تم اتباع قانون بير من حيث مدى التركيز (3-40) لـ (CFT-1-NPT) و (CFT-2 NPT) ، كانت حدود الكشف 1.0096 and 0.8017 g.ml-1على التوالي ، وكانت الامتصاصية المولية 0.7926×104 and 0.5466×104 L.mol1cm-1. 0تُستخدم طريقة تحليل حقن التدفق (FIA) لتقدير السيفتازيديم وتسجيل القياسات باستخدام نهج الأشعة فوق البنفسجية المرئية في الإجراء الثاني. يسمح حقن التدفق بتقدير دقيق للعقار في ظل ظروف تجريبية مثالية. كانت التركيزات في نطاق(3-50) لـ (CFT-1-NPT) و (CFT-2-NPT) ، وكانت حدود الكشف0.8102, 1.2809g.ml-1 . ، والامتصاصية المولية 0.9565×104 ,0.7106×104 L.mol-1. cm-1, على التوالي تم استخدام الأسلوبين المقترحين لتقدير السيفتازيديم في المستحضرات الصيدلانية بنجاح حيث تميزت هذه الطريقة بالبساطة والسرعة والدقة والتكلفة المنخفضة.

Direct determination of piroxicam in pharmaceutical forms using flow injection- spectrophotometry

In this research, direct batch and flow injection (FI) spectrophotometric methods for the analysis of piroxicam (PIX) in commercial dosage forms were investigated. The methods were based on the reaction of PIX with diazotized metoclopramide in alkaline medium to form orange color product at room temperature which absorbs maximally at λmax 472 nm. Chemical and physical variables of batch and FI methods were optimized to produce high sensitivity and reproducibility. Under the optimized experimental conditions, Beer’s law was obeyed over concentration ranges from 1 - 35 and 10 - 250 μg/mL PIX with limits of detection of 0.2 and 3.4 μg/mL and limits of quantification of 0.7 and 11.4 μg/mL PIX for batch and FI procedures, respectively. The relative standard deviation (%RSD) was less than 0.7 and 2.4 for batch and FI procedures respectively with a sample throughput of 38 h-1 for FI procedure. The proposed methods can be used for the routine analysis for the assay of PIX in injections and capsules.
 
 Bull. Chem. Soc. Ethiop. 2020, 34(1), 13-23.
 DOI: https://dx.doi.org/10.4314/bcse.v34i1.2

Spectrophotometric Determination Methyldopa and Salbutamol by Oxidative Coupling, Cloud Point and Flow Injection in Pharmaceutical Formulations

TThree methods study in this research simple, sensitive, an expensive and rapid Oxidative Coupling reaction, Cloud Point Extraction and Flow Injection spectrophotometric methods for determination Methyldopa and Salbutamol, the first method oxidative coupling reaction between the Methyldopa and thiosemicarbazide in presence of ferric nitrate anhydrous to yield dark green colored product that have absorbance at λ max 460 nm. Salbutamol coupling reaction with 4-nitrophenyl hydrazine in presence the potassium Iodide and sodium hydroxide to product the violet colored has absorbance at λ max 530 nm. Beer’s law is obeyed from (1-50) µg/ mL with sandall’s sensitivity (0.039,0.073), correlation coefficient (0.9998) and molar absorptivity (0.536×104,0.327×104) for Methyldopa and Salbutamol respectively. The secondly method to estimation the trace amount of phenolic drugs that product from the oxidative coupling reaction it is cloud point extraction, cloud point extraction enables the drugs to be precisely estimated under the optimal experimental conditions, the maximum absorption at λ max (470,535) nm respectively. The concentration was range (0.25-6) µg/mL, molar absorptivity 0.510×105 ,0.483×105 and enrichment factor (9.51,14.72) respectively for Methyldopa and Salbutamol.Flow injection analysis is simple method to determination the phenolic is based on the measurement of absorption signal for product resulting from oxidative coupling reaction , study all experimental parameters chemical and physical to development and stability the colored of product .Total flow injection of 1.5mL/min was pumped and active material was detect at λ max (460,530)nm respectively for Methyldopa and Salbutamol . In this the proposed methods were suxciffuly, applied to the determination Methyldopa and Salbutamol in pharmaceutical preparation.

Batch and Flow injection Spectrophotometric Methods For Determination of Folic acid in Pharmaceutical Preparations using Cerium(IV) ammonium sulphate(CAS) as an oxidant.

A simple, rapid and sensitive batch and flow injection spectrophotometric methods have been developed for the determination of folic acid (FA) in pure form and in its pharmaceutical preparations. The proposed methods involve the addition of a measured excess of cerium (IV) ammonium sulphate (CAS) in acidic medium followed by determination of unreacted CAS by reacting with a fixed amount of methylene blue (MB) and measuring the absorbance at 665 nm. The optimum reaction conditions and other analytical parameters have been evaluated. Linearity was observed from 1-10 and 4.0-20.0 μg/ml folic acid by batch and flow injection procedures, respectively. Statistical analysis of the results and comparison with results by the British Pharmacopoeia method are also reported.

Determination of nitrofurantoin in pharmaceutical preparations using flow injection-spectrophotometry

Nitrofurantoin (NIT) is used as an antibiotic for the treatment of urinary tract infection. To determine the concentration of NIT in pharmaceutical preparations, two cost-effective extraction-free flow injection (FI) spectrophotometric methods (direct and indirect) were studied. The direct FI method was based on the reaction of NIT with potassium hydroxide and the formation of a red/orange coloured product with absorbance measured at 471nm. The indirect method used a reduction reaction of NIT and involved an oxidative coupling step with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH). The second method resulted in a green coloured product with absorbance measured at 610nm. Both direct and indirect FI methods were in agreement with Beer’s law over a concentration range of 5–300µg/mL. In addition, the limit for detection of the reaction product for direct and indirect method was 1.9 and 4.8µg/mL, respectively. FI spectrophotometric methods used in the present study can be applied for the analysis of NIT in different pharmaceutical dosage forms.

Batch and Flow-Injection Spectrophotometric Determination of Paracetamol by Coupling with Diazotized 4-Aminoacetophenone

Simple, rapid, inexpensive, and sensitive batch and flow injection spectrophotometric methods have been proposed for determination of paracetamol in some pharmaceutical preparations. The proposed methods are based on the coupling reaction between paracetamol and diazotized 4-aminoacetophenone (DAAPH) in a basic medium using sodium hydroxide to produce a pinkish-red azo dye with maximum absorptivity at 500 nm. The reaction conditions and other analytical parameters were studied and optimized for both batch and flow injection procedures. The calibration graphs resulting from measuring the absorbance were linear over the ranges 5.0 ­- 30 and 25 – 180 µg/ml of paracetamol with relative standard deviations 0.26% and 0.18%, and detection limits (0.30, 0.35) µg/ml for batch and flow injection methods respectively. The proposed methods were applied to the analysis of paracetamol in some commercial pharmaceutical preparations. The observed results have a reasonable agreement with those obtained by an HPLC method as a standard certified method from Awamedica company for drug in Erbil-Iraq which based on British pharmacopeia…

Batch and flow injection spectrophotometric methods for the determination of barbituric acid in aqueous samples via oxidative coupling with 4-aminoantipyrine

A batch and flow injection (FI) spectrophotometric methods are described for the determination of barbituric acid in aqueous and urine samples. The method is based on the oxidative coupling reaction of barbituric acid with 4-aminoantipyrine and potassium iodate to form purple water soluble stable product at λ 510 nm. Good linearity for both methods was obtained ranging from 2 to 60 μg mL−1, 5–100 μg mL−1 for batch and FI techniques, respectively. The limit of detection (signal/noise = 3) of 0.45 μg mL−1 for batch method and 0.48 μg mL−1 for FI analysis was obtained. The proposed methods were applied successfully for the determination of barbituric acid in tap water, river water, and urine samples with good recoveries of 99.92% and 100.67% for batch and FI method, respectively.

Flow injection-Spectrophotometric Determination of Phenylephrine Hydrochloride and Amoxicillin Trihydrate in Pharmaceutical Preparations

A batch and flow injection (FI) spectrophotometric methods have been developed for the determination of phenylephrine hydrochloride (PHP) and amoxicillin trihydrate (AMOX) in pharmaceutical preparations. The methods are based on coupling reaction of 2,4dinitrophenylhydrazine (DNPH) with either PHP or AMOX in the presence of sodium hydroxide to form a red colored water-soluble products with absorption maxima at 525 and 515 nm for PHP and AMOX respectively. Optimum conditions for determining the drugs were investigated. Beer’s law were obeyed over the concentration ranges of 2-50μg/ml PHP and 1-40 μg/ml AMOX for batch method, and of 30-1000 μg/ml PHP and50-1200μg/ml AMOX for FIA method. The limits of detection were 1.044 μg/ml PHP and 0.230 μg/ml AMOX for batch method, and for FI method were 14.21 μg/ml PHP and 34.00 μg/ml AMOX. The proposed methods were applied satisfactorilyto the determination of PHP and AMOX in pharmaceutical preparations. The procedures are characterized by its simplicity, accuracy and precision. The results obtained were in good agreement with those obtained using reference standard methods at the 95% confidence level.

Batch and Flow-Injection Spectrophotometric Determination of Procaine HCl in Pharmaceutical Preparations Via Using Diazotization and Coupling Reaction

Simple and sensitive batch and Flow-injection spectrophotometric methods for the determination of Procaine HCl in pure form and in injections were proposed. These methods were based on a diazotization reaction of procaine HCl with sodium nitrite and hydrochloric acid to form diazonium salt, which is coupled with chromatropic acid in alkaline medium to form an intense pink water-soluble dye that is stable and has a maximum absorption at 508 nm. A graphs of absorbance versus concentration show that Beer’s law is obeyed over the concentration range of 1-40 and 5-400 µg.ml-1 of Procaine HCl, with detection limits of 0.874 and 3.75 µg.ml-1 of Procaine HCl for batch and FIA methods respectively. The FIA average sample throughput was 70 h-1. All different chemical and physical experimental parameters that affecting on the development and stability of the colored product were carefully studied and the proposed methods were applied satisfactorily for the determination of Procaine HCl in an injections samples using the standard addition method.

Batch and Flow-Injection Spectrophotometric Determination of Procaine HCl in Pharmaceutical Preparations Via Using Diazotization and Coupling Reaction

Simple and sensitive batch and Flow-injection spectrophotometric methods for the determination of Procaine HCl in pure form and in injections were proposed. These methods were based on a diazotization reaction of procaine HCl with sodium nitrite and hydrochloric acid to form diazonium salt, which is coupled with chromatropic acid in alkaline medium to form an intense pink water-soluble dye that is stable and has a maximum absorption at 508 nm. A graphs of absorbance versus concentration show that Beer’s law is obeyed over the concentration range of 1-40 and 5-400 µg.ml-1 of Procaine HCl, with detection limits of 0.874 and 3.75 µg.ml-1 of Procaine HCl for batch and FIA methods respectively. The FIA average sample throughput was 70 h-1. All different chemical and physical experimental parameters that affecting on the development and stability of the colored product were carefully studied and the proposed methods were applied satisfactorily for the determination of Procaine HCl in an injections samples using the standard addition method.

Flow injection spectrophotometric and spectrofluorimetric methods for the determination of candesartan cilexetil in pharmaceutical formulations

This article describes the development of flow injection methods for the determination of Candesartan Cilexetil using spectrophotometery and spectrofluorimetry in pharmaceutical formulations. The first method is based on the UV absorption at 270 nm in phosphate buffer containing cetyl trimethylammonium bromide (CTAB) and methanol at pH 6.5. The second method based on the fluorescence excitation and emission at 260 and 384 nm respectively, in phosphate buffer containing sodium dodecyl sulphate (SDS) and methanol at pH 4.0. Calibration graphs were linear over the concentration range of 0.1 to 4.0 µg/ml for UV-method and 0.03 to 2.0 µg/ml for fluorescence method. The limits of detection (3 s) of 0.01 µg/ml for both methods with sample throughput of 80 and 100/h were obtained respectively. The relative standard deviations of 1.2 to 3.2% (n = 4) for UV-method and 0.5 to 1.8% for fluorescence method were achieved in the concentration range studied. The developed methods were applied to pharmaceuticals and the results obtained were compared with HPLC reference method and no significant difference between these methods was observed at 95% confidence level. Key words: Candesartan cilexetil, spectrophotometery, spectrofluorimetry, pharmaceuticals, flow injection analysis.

BATCH AND FLOW INJECTION SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF PARACETAMOL IN PHARMACEUTICAL PREPARATIONS VIA OXIDATIVE COUPLING WITH 4-AMINOANTIPYRINE

A simple, rapid and sensitive batch and flow injection spectrophotometric methods have been developed for the determination of paracetamol in pure form and pharmaceutical preparations. The proposed methods are based on the oxidative coupling reaction of paracetamol with 4-aminoantipyrine in presence of ammonium persulfate in alkaline medium to produce an orangereddish product that having absorptivity maximum at 461 nm. The optimum reaction conditions and other analytical parameters have been evaluated. Linearity was observed from 2-16 and 100-700 g mL -1 paracetamol by batch and flow injection procedures, respectively. Statistical analysis of the results and comparison with results by the British Pharmacopoeia method are also reported.

Optimization of Two Flow-Injection Spectrophotometric Methods for the Determination of Indapamide in Pharmaceutical Dosage Forms

Multivariate experimental design has been used to optimize 2 flow-injection spectrophotometric methods for the determination of indapamide in pharmaceutical dosage forms, both pure and commercial tablets. The methods are based on the oxidation of this drug with iron (III) in acidic medium and the subsequent formation of an intensive orange-red complex between the liberated iron (II) and 2,2'-bipyridyl or 1,10-phenanthroline reagents. Plackett-Burman designs were applied as a screening method to evaluate the most significant factors with few experiments. Central composite 2(3)+ star designs were performed to evaluate the response surfaces. The methods have been fully validated and were applied successfully to the determination of indapamide in pure and pharmaceutical forms with good accuracy and precision. Therefore, the 2 proposed procedures are simple, inexpensive, and rapid flow methods for the routine determination of indapamide in pharmaceutical preparations.

Development of flow injection spectrophotometric methods for the determination of free available chlorine and total available chlorine: comparative study

A comparative study on the development of flow-injection (FI) spectrophotometric methods for the determination of free available chlorine (FAC) and total available chlorine (TAC) is described. The use of o-dianisidine (ODS), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonate (ABTS), 4-nitrophenylhydrazine (4-NPH), methyl orange (MO), syringaldazine (SYR) and a new reagent, indigo carmine (IC), in a flow-injection set-up was optimized for common FI operating parameters such as carrier composition, flow-rate, pH, length of reaction coil and injection volume. The FI conditions were designed by the choice of acid at suitable concentration in the carrier stream such that response from FAC is maximized while at the same time minimally interfered by combined available chlorine (CAC). Analytical characteristics of the FI method using these reagents such as detection limits, linear range, selectivity and their relative stability were compared and contrasted. The reagent that yielded the most sensitive signal is ABTS and is least interfered by Mn 2+, Zn 2+ and Cu 2+ but interference from CAC was the most severe, while SYR and 4-NPH were least affected by CAC. IC exhibited the best selectivity characteristics amongst all the reagents studied. TAC can be conveniently determined by adding NaBr to the carrier stream. Finally, some of the promising reagents were applied to the analysis of a few commercial disinfecting formulations. Good agreement on the TAC (FAC + CAC) content was found between the proposed FIA and the manual iodimetric methods.

Flow-Injection Spectrophotometric Determination of Diclofenac or Mefenamic Acid in Pharmaceuticals

Two flow injection (FI) spectrophotometric methods are proposed for the determination of diclofenac (DCF) or mefenamic acid (MF) in bulk samples and pharmaceuticals. Both methods are based on the reaction of DCF or MF with potassium ferricyanide in a sodium hydroxide medium. The absorbance of the orange products obtained is measured at 455 nm for DCF and 465 nm for MF. The corresponding calibration graphs are linear over the range 0.20–20.0 mg L−1 for DCF and 1.00–100 mg L−1 for MF, while the limits of detection were 0.05 and 0.18 mg L−1, respectively.

On-line microwave FIA technique and its application to determination of rhodium and sequential determination of palladium and rhodium

An on-line microwave oven was employed in this study to accelerate the coordination reactions between Rh(III), Pd(II), and 2-(3,5-dicloro-2-pyridyl-azo)-5-dimethylaminoaniline (3,5-diCl-PADMA) in HOAc-NaOAc media. Two sensitive flow-injection spectrophotometric methods have been established for the determination of Rh and sequential determination of Rh and Pd, respectively. Two important parameters in on-line Microwave-FIA, T1 and T2, were investigated. The difference in the effect of the microwave irradiation on the reactions was explained. The proposed methods are applied to the determination of Rh in the waste and sequential determination of Pd and Rh in artificial samples with satisfactory results. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:91–96, 2000

Flow-injection spectrophotometric methods for the determination of tenoxicam

Two sensitive and rapid flow-injection spectrophotometric methods are proposed for the determination of tenoxicam (TX). In the first method, a Fe(III)–tenoxicam complex is formed in a methanolic medium and the absorbance is measured at 540 nm, while the second method involves measurement of the absorbance at 355 nm of a solution containing the drug in hydrochloric acid medium. In both methods, the peak heights were proportional to tenoxicam concentration over the ranges 7.0–320 and 0.5–8.5 mg l −1, respectively. The methods have been applied to the routine determination of the drug in dosage forms.

Flow-injection spectrophotometric determination of frusemide or sulphathiazole in pharmaceuticals

Two sensitive and fast flow-injection spectrophotometric methods are proposed for the determination of frusemide or sulphathiazole based on the formation of coloured complexes between these compounds and Pd(II) at pH 5.0 and 55°C. Using the peak height as a quantitative parameter, frusemide or sulphathiazole was determined at 410 nm over the range 2.0 × 10 −5–4.0 × 10 −4 M or 5.0 × 10 −5–3 × 10 −4 M, respectively. The methods were applied to the determination of these sulphonamides in pharmaceuticals.