Determination of Tranexamic Acid Using Ethyl Chloroformate as Derivatizing Reagent in Pharmaceutical Preparations and Blood by GC

Ethyl chloroformate was used as a derivatizing reagent to develop a simple and sensitive gas chromatographic procedure for the determination of tranexamic acid. Analysis was performed on an HP-5 column (30 m × 0.32 mm i.d.) coupled with mass spectrometric detection. Linear response was obtained from 60 to 500 pg with a limit of detection of 20 pg tranexamic acid injected onto the column. Aminocaproic acid was used as an internal standard. Tranexamic acid was determined in pharmaceutical preparations and blood samples after therapy with the drug. Appoximately 2.0 μg mL^?1 was found in blood samples. Relative standard deviation for analysis was within 0.1–0.4% (n = 3). Recovery of tranexamic acid added to deprotenized serum was 99.6% with an RSD of 1.2–1.6% (n = 3). Pharmaceutical additives and amino acids, if also present, did not affect the determination.     

Spectrophotometric and Spectrofluorimetric Determination of Famotidine and Ranitidine Using 1,4-Benzoquinone Reagent

ABSTRACT

Spectrophotometric and spectrofluorimetric methods were adopted for the analysis of Famotidine and Ranitidine depending on their reaction with 1,4 Benzoquinone reagent at pH 5.2 and 5.6, respectively. The absorbances of the resulting condensation products were measured at 502 and 508 nm for Famotidine and Ranitidine, respectively. Concentrations adhering to Beer's law were from 40-160 μg.ml^? for Famotidine and from 20-100 μg.ml^? for Ranitidine.

Furthermore the resulting condensation products exhibited fluorescence at 665 nm when excited at 290 nm and the calibration graphs were rectilinear from 0.4-1.4 μg.ml^? for Famotidine and from 0.21 μg.ml^? for Ranitidine.

Different parameters affecting these reactions were thoroughly studied. Also these methods were applied to the pharmaceutical preparations and the results were satisfactory. The validities of the methods were ascertained by the standard addition technique revealing fine results in consideration to the mean recovery percent and standard deviation.

The spectrofluorimetric method was a hundred times more sensitive then the spectrophotometric method. The proposed methods were sensitive, accurate, and precise as statistically compared with the official methods of analysis of Famotidine and Ranitidine.     

Kinetic Spectrophotometric Determination of Famotidine in Pharmaceutical Preparations

A kinetic method for the accurate and sensitive determination of famotidine has been described. The method is based on the alkaline oxidation of famotidine with potassium permanganate at a fixed time of 10 min. The formed manganate ion is measured at 610 nm. The concentration of famotidine is calculated using the calibration equation for the fixed time method. Beer's law was obeyed in the range of 1–10 μg/mL and the R.S.D. (n = 10) was 0.47%. The method has been applied successfully to commercial tablet dosage form.     

Capillary GC Analysis of Glyoxal and Methylglyoxal in the Serum and Urine of Diabetic Patients After Use of 2,3-Diamino-2,3-dimethylbutane as Derivatizing Reagent

The dicarbonyl compounds glyoxal, methylglyoxal, and dimethylglyoxal have been separated by capillary GC on a 30 m × 0.32 mm i.d. HP-5 column after precolumn derivatization with 2,3-diamino-2,3-dimethylbutane at pH 4. Chromatographic separation was complete in 6 min. Nitrogen was used as carrier gas at a flow rate of 2 mL min^?1. Split injection was performed with a split ratio of 10:1 (v/v). The derivatives were monitored by flame-ionization detection, and linear calibration plots were obtained in the ranges 0.06–0.69, 0.05–1.01, and 0.07–1.33 μg mL^?1 for glyoxal, methylglyoxal, and dimethylglyoxal, respectively; the respective detection limits were 20, 10, and 10 ng mL^?1. Glyoxal and methylglyoxal were analyzed in serum and urine from diabetics and from healthy volunteers. Amounts of glyoxal and methylglyoxal in serum from diabetic patients were 0.19–0.33 and 0.20–0.29 μg mL^?1, respectively, with respective relative standard deviations (RSD) of 0.8–1.0 and 0.8–1.1%. Amounts of glyoxal and methylglyoxal in serum from healthy volunteers were 0.05–0.08 and 0.04–0.10 μg mL^?1, respectively, with respective RSD of 0.9–1.2 and 1.0–1.2%. Levels of glyoxal and methylglyoxal in urine from diabetic patients were 0.18–0.40 and 0.25–0.36 μg mL^?1, respectively.     

Determination of Guanidino Compounds in Serum by Micellar Electrokinetic Capillary Chromatography Using Benzoin as the Derivatizing Reagent

An analytical procedure has been evolved for the determination of seven guanidino compounds; guanidine (G), methylguanidine (MG), guanidinoacetic acid (GAA), guanidinopropionic acid (GPA), guanidinobutyric acid (GBA), arginine (Arg), and guanidinosuccinic acid (GSA) by micellar electrokinetic capillary chromatography (MEKC) within 6 min using benzoin as derivatizing reagent. Sodium dodecyl sulfate (SDS) was used as the micellar medium in a sodium tetraborate (0.1 M) buffer at pH 8.5. Uncoated fused silica capillary was used with an effective length of 39 cm and 75 μm id. Applied voltage was 25 kV and photo diode array detection was set at 228 nm. Linear calibrations obtained from 0.057 to 14.11 μmol/L and limits of detection (LOD) were within 0.019–0.03 μmol/L. The derivatization and separation was repeatable with relative standard deviation (RSD) within 1.9–3.8%. Serum of healthy volunteers and uremic patients was analyzed and amounts found in uremic patients were G 1.98–3.03, MG 1.21–1.79, GAA 3.67–6.09, GPA 1.17–1.37, GBA 1.29–1.46, Arg 9.49–19.17, and GSA 6.83–10.91 μmol/L with RSD (n = 4) within 1.3–4.5%. The amount of guanidino compounds was higher in uremic patients than in healthy volunteers.     

Ethyl Chloroformate as a Derivatizing Reagent for Capillary GC Determination of Dopamine, Adrenaline, Putrescine, and Histamine

Putrescine (Pu), histamine (HA), phenylhydrazine (PHZ), octopamine (OA), dopamine (DA), adrenaline (AD), and noradrenaline (NA) as the ethyl chloroformate (ECF) derivatives have been analyzed by capillary gas chromatography. The derivatives were separated on a 30 m × 0.32 mm i.d. HP-5 column by temperature programming from 100 °C (held for 1 min) to 250 °C at 10 min^?1. The total run time was 16 min. Nitrogen was used as carrier gas at a flow rate of 4 mL min^?1 and detection was by FID. PHZ was used as internal standard. The split ratio was 10:1 (v/v). The calibration curves were linear in the range 4–60 ng injected (1 μL injection) with detection limits 1.3–4.0 ng per injection (1 μL). When the method was used for determination of DA and AD in pharmaceutical preparations the relative standard deviation (RSD) was in the range 1–2.5%. When the effect of several additives was tested these did not affect the analyses. Pu and HA were estimated in fish samples with RSD 0.9–1.1 and 0.9–1.2%, respectively.     

Determination of Ranitidine Hydrochloride in Pharmaceutical Preparations by Ultraviolet and Visible Spectrophotometry

Abstract

Ranitidine hydrochloride in tablets (T) and injections (I) was determined by ultraviolet spectrophotometry (UVS) at 313 nm and visible spectrophotometry (VISS) at 615 nm, after reaction with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) and ferric chloride. For UVS, Beer's law was obeyed in the range 5.0 – 18.0 μg/mL. The coefficients of variation (CV) for the samples T were 0.36% and 0.71% and for the samples I were 0.51% and 0.24%. The recovery average (RA) was 99.88%. For UVS, Beer's law was observed in the range 1.44 – 5.76 μg/mL. The CV for T were 0.72% and 0.59%, and for I were 0.53% and 0.61%. The RA was 99.39%. The precision and accuracy of the two methods were compared.     

Simultaneous Determination of Rosiglitazone and Metformin in Pharmaceutical Preparations by LC

In the present study, a novel, fast and simple liquid chromatographic method was developed and validated for the simultaneous determination of rosiglitazone and metformin in pharmaceutical preparations. The separation was achieved on a phenyl column (250 × 4.6 mm i.d., 5 μm) using a mobile phase composed of acetonitrile:10.0 mM phosphate buffer pH 5.5 (70:30, v/v). The flow rate was 1 mL min⁻¹. UV detection was performed at 245 nm and verapamil was used as internal standard. The developed method was validated in terms of stability, specificity, sensitivity, linearity, accuracy, precision and robustness. The limit of quantification was 0.02 μg mL⁻¹ for both drugs. The method developed was successfully applied to the simultaneous determination of rosiglitazone and metformin in pharmaceutical preparations. The results were compared to two methods reported in the literature and no significant difference was found statistically.     

Determination of Adrenaline by Atomic Absorption Spectrometry Using Copper as Probe Reagent in Pharmaceutical and Serum Samples

In this paper, an atomic absorption spectrometric method has been established to determine adrenaline using Cu(II) as probe reagent. In the presence of SCN^?, it has been demonstrated that Cu(II) is reduced to Cu(I) by adrenaline at pH 6.0, and the in situ formed Cu(I) reacts with SCN‐ to form the white emulsion of CuSCN. According to the amount of residual Cu(II) which is measured by atomic absorption spectrometry, the amount of adrenaline can be determined indirectly. Beer's law is obeyed in the range of adrenaline concentration of 0.080‐6.00 mg mL‐1, and the linear regression equation is A = 0.20342 ‐ 0.02756C (μg mL^?1) with a correlation coefficient of 0.9998. The detection limit is 0.033 μg mL^?1 and R.S.D. is 0.56%. This method has been successfully applied to determine adrenaline in pharmaceutical and serum samples with satisfactory results.     

Simultaneous Determination of Pioglitazone,Metformin, and Glimepiride in Pharmaceutical Preparations using HPTLC Method

JPC – Journal of Planar Chromatography – Modern TLC - A simple, precise, and accurate high-performance thin-layer chromatography (HPTLC) method for the simultaneous determination of...     

Spectrofluorimetric Determination of Piroxicam in Pharmaceutical Preparations and Spiked Human Serum Using Micellar Media

The fluorescence properties of piroxicam in various micellar media were investigated. It was found that the presence of 0.05M sodium dodecyl sulfate (SDS) surfactant (pH 1.5–2, nitric acid) causes an approximately 5-fold enhancement in the fluorescence of this drug. An experimental design approach based on central composite design was used to investigate the influence of the main variables (pH, SDS concentration and temperature) on the fluorescence signal. Based on the obtained results, a micelle-enhanced fluorescence method was developed for the determination of piroxicam in pharmaceuticals and also in spiked human serum (after extraction with diethyl ether). The linear calibration ranges of the methods were 0.05–1.5 and 0.2–10µgmL^–1 for aqueous solution and serum samples, respectively. The detection limits were 0.015 and 0.10µgmL^–1 in aqueous and serum samples, respectively.Received November 24, 2002; accepted April 13, 2003 Published online August 8, 2003     

Liquid Chromatographic Determination of Glutamine in Cerebrospinal Fluid Using 2-Hydroxynaphthaldehyde Derivatizing Reagent

Summary An analytical procedure has been developed for the selective determination of glutamine from cerebrospinal fluid (CSF) using 2-hydroxynaphthaldehyde derivatizing reagent. Arginine and tyramine could also be determined simultaneously. Separation was on a Phenomenex C-18, (150 × 4.6 mm i.d.) column with methanol: water (63:38 v/v) mobile phase at 1mL min^–1 and UV detection at 330nm. Detection limits for glutamine, arginine, and tyramine were 2.8 ng, 17.4 ng and 3.45 ng injection^–1 (5 L), respectively. A large number of amines and amino acids eluted did not affect the determination of glutamine. The analysis of CSF of four patients suffering from hydrocephalus for glutamine indicated concentrations within range 37.4–11.24 g mL^–1 with coefficient of variation 3.0–6.2%.     

Spectrophotometric Determination of Ceftazidime in Pharmaceutical Preparations Using Neocuproin as a Complexing Agent

Abstract

A simple and reproducible spectrophotometric method for the assay of ceftazidime with neocuproin-copper(II) reagent has been developed. The procedure is based on the drug in an acidic medium, subsequent formation of yellow ternary complex in citrate buffer solution (pH 4.2), and measurement at 454 nm. Beer's law is obeyed in the range 15.0–40.0 µg mL^?1 with correlation coefficient r ² = 0.9995. The procedure holds good accuracy and precision when applied to the analysis of ceftazidime in powder for injection with good recovery percent ranging from 100.17±1.0 without interference from additives.     

Diazotised 4-Nitroaniline as a Chromogenic Reagent for the Determination of Indole Derivatives in Certain Pharmaceutical Preparations

Abstract

A sensitive colorimetric method has been devised for microdetermination of six indole derivatives; ergotamine tartrate, methylergometrine maleate, dihydroergocornine methanesulphonate, dihydroergocristine methanesulphonate, dihydroergocryptine methanesulphonate and pindolol, both in pure form and in pharmaceutical preparations. The method is based on the reaction of indole moiety with diazotised 4-nitroaniline in buffer solution of pH 6 to produce a stable yellow monoazo dye. Beer's law is obeyed over final concentration ranges 8–32 μgm1^?1 for ergotamine tartrate, 4–48 μgml^?1 for methylergometrine maleate, 8–56 μgml^?1 for dihydro-ergot alkaloids and 1–10 μgml^?1 for Pindolol with apparent molar absorptivity range (7.62 × 10³?2.61 × 10⁴) 1.mole^?1.cm^?1. A study has been made to determine the optimum conditions of the colour reaction.     

Determination of Water Soluble Vitamins in Pharmaceutical Preparations Using Liquid Chromatography

Abstract

A liquid chromatography procedure is described for the simultaneous separation of seven water soluble vitamins in pharmaceutical pteparations. The vitamins are separated on a CR bonded-phase column and eluted with a gradient solvent program. A microprocessor controlled variable wavelength ultraviolet detector is used to automatically change detection wavelength to optimize detection of each vitamin. Pharmaceutical preparations are briefly sonicated in a dimethyl sulfoxide-water mixture, centrifuged, and an aliquot injected directly onto the column.     

Flow Injection Spectrophotometric Determination of Dipyrone in Pharmaceutical Formulations Using Fe(III) as Reagent

A flow injection spectrophotometric procedure with symmetric merging zones for dipyrone determination in pharmaceutical formulations is proposed. The determination is based on the formation of a blue complex (monitored at a wavelength of 642 nm) yield in the complexation reaction of dipyrone with Fe(III) in acid medium. Under optimum conditions, a calibration curve was obtained from 3.5 to 281 mg L^?1 with a detection limit of 2.8 mg L^?1 and the samples throughput was 80 h^?1. The analytical results obtained for commercial formulation samples by applying the proposed method were in good agreement with labeled values and those obtained by a comparative procedure at a 95% confidence level.     

Spectrophotometric Determination of Metoclopramide in Pharmaceutical Preparations

A simple and rapid spectrophotometric method for the determination of metoclopramide is described. The method is based upon simple diazotization reactions with nitrite and aniline as the coupling reagent. The absorbance was measured at 410 nm. The method was optimized for acidity, the amount of reagents required, and the amount of sodium hydroxide. The range of linearity was 0.5–12.0 µg/mL. The method was successfully applied to the determination of metoclopramide in pharmaceutical preparations without any interference from common excipients.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 711–714.Original English Text Copyright © 2005 by Shah, Rasul Jan, Azam Khan, Amin.The text was submitted by the authors in English.     

TLC-Densitometric Determination of Azithromycin in Pharmaceutical Preparations

JPC – Journal of Planar Chromatography – Modern TLC - A thin-layer chromatographic method with densitometric detection has been established for quantification of azithromycin in...     

Resin Bead Detection and Spectrophotometric Determination of Ascorbic Acid in Pharmaceutical Preparations Using m-Dinitrobenzene

Abstract

A colorimetric reaction has been studied for the detection and determination of ascorbic acid in samples at the microgram level. the method is simple, rapid, and sensitive, the ascorbic acid was detected using resin beads and determined spectrophotometrically using m-dinitrobenzene in formaldehyde. the detection limit was 10μg. Beer's law is obeyed in the concentration range of 2 – 50μg/ml of ascorbic acid.     

Spectrophotometric Determination of Methyldopa in Pure and Pharmaceutical Preparations

Abstract

Methyldopa reacts with barbituric acid to give a red colour having maximum absorbance at 540 nm. The reaction is selective for methyldopa with 0.01 mg/ml as visual limit of quantitation and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer's Law from 0.1 mg to 2.5 mg/10 ml of methyldopa and the relative standard deviation is 1.1%. The quantitative assessment of tolerable amount of other drugs is also studied.