University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Pharmaceutical

Classification: Pharmaceutical -> capsule

Citations 25

"Specific Spectrofluorometric Quantification Of D-penicillamine In Bulk And Dosage Forms After Derivatization With 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole"
Anal. Chim. Acta 2000 Volume 408, Issue 1-2 Pages 169-175
A. A. Al-Majed

Abstract: A specific and sensitive fluorometric method is proposed for the determination of D-penicillamine in pure form and pharmaceuticals. The method is based on coupling between D-penicillamine and 4-fluoro-7-nitrobenzo-2-oxa-1,3-dizole (NBD-F) to produce the corresponding fluorescent NBD-penicillamine. The optimum conditions for the reaction were carefully investigated and incorporated into the procedure. The reaction was proceeded in berate buffer (pH 7.2) containing 20% of ethanol to give intense fluorescence having its excitation and emission wavelengths at 465 and 530 nm, respectively. The fluorescence intensity was a linear function of the drug concentration over the range of 0.6-3 µg mL-1. Regression analysis of the concentration fluorescence intensity showed good correlation (r = 0.9975) with a detection limit of 2 x 10^-3 µg mL-1 (1.3 x 10^-8 M). The mean of percentage recoveries of added authentic drug was 100.00±1.05. The method was applied successfully to the determination of this drug in pharmaceutical dosage form. The mean recovery for the commercial capsules was 98.1±0.54%. The results were sufficiently accurate, precise and comparable with those obtained from the official method. The method is specific for the intact drug, and can be adopted in the presence of possible interferences.
Penicillamine D Fluorescence Interferences Optimization Method comparison

"Spectrophotometric Estimation Of D-penicillamine In Bulk And Dosage Forms Using 2,6-dichloroquinone-4-chlorimide (DCQ)"
J. Pharm. Biomed. Anal. 1999 Volume 21, Issue 4 Pages 827-833
A. A. Al-Majed

Abstract: A simple colorimetric method for the determination of D-penicillamine in pure form and pharmaceutical formulations is described. The method is based on coupling between D-penicillamine and 2,6-dichloroquinone-4-chlorimide (DCQ) in dimethylsulfoxide. The optimum conditions for the reaction were investigated and incorporated into the procedure. The reaction forms a yellow 1:1 complex with maximum absorbance at 431 nm (epsilon = 3700). Regression analysis of Beers plot showed good correlation (r = 0.9998) and the calibration graph was rectilinear over the range 4-20 µg mL-1 with a detection limit of 0.15 µg mL-1. The average recovery for the commercial capsules was 101.66% with an RSD of 1.57%. The results obtained were sufficiently accurate, reproducible and in accordance with those given by the official method. The method is specific for the intact drug, and can be adopted in the presence of some interfering substances.
Penicillamine D Spectrophotometry Interferences Standard method Optimization

"Determination Of Flufenamic Acid And Mefenamic Acid In Pharmaceutical Preparations And Biological Fluids Using Flow Injection Analysis With Tris(2,2 -bipyridyl)ruthenium(II) Chemiluminescence Detection"
Anal. Chim. Acta 2000 Volume 416, Issue 1 Pages 87-96
Fatma A. Aly, Salma A. Al-Tamimi and Abdulrahman A. Alwarthan

Abstract: A novel chemiluminescent method using flow injection has been investigated for the rapid and sensitive determination of flufenamic and mefenamic acids. The method is based on a tris(2,2-bipyridyl)ruthenium(III) chemiluminescence reaction. Ru(bipy)(3)(3+) is chemically generated by mixing two streams containing solutions of tris(2,2-bipyridyl)ruthenium(II) and acidic cerium(IV) sulfate. After selecting the best operating parameters calibration graphs were obtained over the concentration ranges 0.07-6.0 and 0.05-6.0 µg mL-1 for flufenamic acid and mefenamic acid, respectively. The Limits of detection (s/n = 3) were 3.6 x 10^-9 M flufenamic acid and 2.1 x 10^-7 M mefenamic acid. The method was successfully applied to the determination of these compounds in pharmaceutical formulations and biological fluids. A proposal for the reaction pathway was given.
Flufenamic acid Mefenamic acid Chemiluminescence Method comparison Optimization

"Determination Of Ofloxacin Using A Chemiluminescence Flow Injection Method"
Anal. Chim. Acta 2000 Volume 416, Issue 2 Pages 227-230
Yi Rao, Yan Tong, Xinrong Zhang, Guoan Luo and Willy R. G. Baeyens

Abstract: A new chemiluminescence (CL) flow injection method was proposed for the determination of ofloxacin in pharmaceuticals in the range 0.04-4 µg mL-1 with a detection limit of 0.016 µg mL-1 and a relative standard derivation (RSD) of 2.2% at 0.4 µg mL-1 (n=10). The method is based on the CL reaction of cerium(IV) with sulfite sensitized by ofloxacin. The established procedure could be applied to the determination of ofloxacin in tablet, capsule and injection in agreement with the results obtained by using reported methods.
Ofloxacin Chemiluminescence Method comparison

"Flow Injection Spectrophotometric Determination Of Paracetamol In Pharmaceuticals By Means Of Online Microwave-assisted Hydrolysis And Reaction With 8-hydroxyquinoline (8-quinolinol)"
Anal. Chim. Acta 1996 Volume 330, Issue 1 Pages 59-69
Zouhair Bouhsain, Salvador Garrigues, Angel Morales-Rubio and Miguel de la Guardia*

Abstract: An automated flow injection spectrophotometric method was developed for determining paracetamol in pharmaceuticals. The method was based on the alkaline hydrolysis of paracetamol to yield p-aminophenol which was reacted with 8-hydroxyquinoline in the presence of potassium periodate oxidant to form a blue indophenol dye. An extract of the pharmaceutical preparation in 1.5 M NaOH was injected into a 1.5 M NaOH carrier stream (1.9 ml/min) via a 500 µL sample loop and passed through a reaction coil (6 m x 0.8 mm i.d.) mounted in a focused microwave cavity operating at 200 W. The flow was then merged with 4 mM KIO3 and 2.76 mM 8-hydroxyquinoline (both in 1.5 M NaOH and at 1.9 ml/min) and the absorbance was measured at 608 nm (70 µL detection cell). Calibration graphs were linear up to 158 µM-paracetamol with a detection limit of 1.25 µM and RSD (n = 5) for 39.7 µM-paracetamol of 1.9%. The method was applied to tablets, capsules, syrup and suppositories. The recoveries of 10.6-31.7 µM-paracetamol from spiked pharmaceutical formulations were 96.3-102%. The sampling frequency was 70/h.
Acetaminophen Spectrophotometry Microwave 8-Hydroxyquinoline

"FIA - FTIR Determination Of Ibuprofen In Pharmaceuticals"
Talanta 1993 Volume 40, Issue 1 Pages 89-93
Salvador Garrigues, Maximo Gallignani and Miguel de la Guardia

Abstract: Ibuprofen (I) capsules were powdered and dissolved in CCl4, which did not solubilize the water-soluble excipients and allowed the direct determination of I without additional sample pre-treatment. The filtered extract (320 µL) was injected into a carrier stream of CCl4 at 0.28 mL min-1 and fed to a flow-through cell where the FTIR spectrum was monitored at 1900 and 1500 cm-1. The absorbance of the carbonyl band was measured at 1710 cm-1 as a function of time, and the peak height was used to calculate the concentration. of I from calibration graphs. The detection limit was 0.08 mg mL-1 of I at a sample throughput of 20 h-1. The calibration graph was rectilinear in the range 0.5 to 20 mg mL-1 of I and the coefficient of variation (n = 5) was 0.8% for the determination of 10 mg mL-1 of I. The results were comparable with those from UV spectrophotometry, but free from matrix interferences.
Ibuprofen Spectrophotometry Interferences Method comparison

"Immobilization Of Reagents By Polymeric Materials. Determination Of Metamizol"
Talanta 1993 Volume 40, Issue 7 Pages 1067-1071
L. Lahuerta Zamora and J. Martinez Calatayud,

Abstract: Lead dioxide (26.4 g) was stirred with 15.1 g of polyester resin solution (Reposa Al-100) containing low mol. wt. polyester chains and a Co activating agent. Then 0.4 mL of methylethyl ketone was added and stirring was continued until polymerization was complete. The resulting solid was dried in air for 2-3 h, broken into small pieces and ground to a powder in a mechanical grinder. Particles in the size range 200-300 µm were packed in a packed bed reactor (31 cm x 1.5 mm). Metamizole (dipyrone) injections, capsules or solution was dissolved in water and 384.5 µL injected into a 0.1 M HClO4 carrier stream (3 ml/min) for the indirect determination of dipyrone based on the oxidation of dipyrone in HClO4. The resulting Pb(II) was determined by AAS at 217 nm. The calibration graph was rectilinear for 1-6 µg/ml of dipyrone and at 3 µg/ml the RSD was 1.6% (n = 42). Paracetamol interfered seriously but there was no interference from 100 µg/ml of caffeine, dexamethasone or thiamine, 50 µg/ml of lignocaine hydrochloride or pyridoxine, or from 5 µg/ml of ascorbic acid. A method for immobilization of inorganic reagents, based on the dispersion of the reagent into an unsaturated polyester solution is applied to immobilization of lead dioxide. The obtained solid is of application in a flow injection manifold for indirect atomic absorption determination of metamizol in pharmaceutical formulations. The procedure gives a linear calibration graph up to 6 ppm of metamizol with a relative standard deviation of 1.6% (3.0 mg/l) and a sample throughput of 72 hr-1. [References: 9]
Metamizol Spectrophotometry Immobilized reagent Indirect Interferences

"Flow Injection Determination Of Drugs By Specific Detection Of Carboxylic Acids"
Analyst 1988 Volume 113, Issue 11 Pages 1673-1675
Toshifumi Takeuchi, Yozo Kabasawa, Rikizo Horikawa and Takenori Tanimura

Abstract: A variety of carboxylic acid drugs were determined. A portion, containing ~0.25 mmol of drug, of the powder obtained from 20 tablets or capsules was extracted with ethanol or water, the extract was filtered, and the filtrate was analyzed in a flow injection system in which it was treated with 0.02 M 2-nitrophenylhydrazine in 0.2 M HCl and 0.05 M 1-ethyl-3-(3-dimethylaminopropyl)carbodi-imide in ethanolic 4% pyridine in the first reaction coil (10 m x 0.5 mm) at 60°C and with 1.5 M NaOH in a second coil of the same dimensions and temperature After cooling to 30°C in a third coil (1 m x 0.5 mm) the absorbance was measured at 540 nm. Satisfactory results were obtained for aspirin, ibuprofen, dehydrocholic acid, nicotinic acid and tranexamic acid, with recoveries of 99.9 to 103.4% and coefficient of variation (n = 10) of 0.8%.
Drugs Aspirin Ibuprofen Dehydrocholic acid Nicotinic acid Tranexamic acid Spectrophotometry Heated reaction

"Determination Of Ascorbic Acid By Flow Injection With Chemiluminescence Detection"
Analyst 1993 Volume 118, Issue 6 Pages 639-642
Abdulrahman A. Alwarthan

Abstract: Flow injection and chemiluminescence detection were used to determine 30 amol of ascorbic acid based on the reducing effect of ascorbic acid on Fe(III) and measuring the Fe(II)-catalyzed light emission from luminol oxidation by H2O2. The method was used to determine ascorbic acid levels in tablets, capsules, syrup and fruit juices. The flow cell was a coil made of 1.3 mm i.d. glass tubing spiralled to a diameter of 35-mm. The photomultiplier tube was operated at 400 V. The acidified Fe(III) solution was used as the carrier stream for the sample which was acidified with 1% metaphosphoric acid. The luminol was mixed with the carrier solution at the reaction coil. Each solution was pumped (2.03 mL min-1) by a peristaltic pump. The calibration plot was rectilinear from 10 pM to 100 nM ascorbic acid. The detection limit was 30 amol. The coefficient of variation (n = 10) was 1.4% (for an injection of 1 µM). Recoveries ranged from 90.8 to 101.1% and 95.5 to 106.4% for pharmaceutical preparations and fruit juices, respectively.
Ascorbic acid Chemiluminescence

"Flow Injection Analysis And Batch Procedures For The Routine Determination Of N-penicillamine"
Microchem. J. 1990 Volume 41, Issue 1 Pages 2-5
P. Viñas, J.A. Sanchez-Prieto, M.Hernandez Cordoba

Abstract: A capsule was dissolved in water to 250 mL and a suitable portion of the solution was treated with 1 mM Co(II) solution (2.5 ml) and 2 M ammonium acetate (2.5 ml). The mixture was diluted to 25 mL and the absorbance of the yellow complex was determined at 360 nm. Calibration graphs were rectilinear for 0.02 to 0.3 mM of penicillamine. The method was modified for flow injection analysis using peak-height or peak-width methods; in both cases the flow rates were maintained at 3.3 mL min-1. For the peak-height technique, calibration graphs were rectilinear for 0.1 to 2 mM; the sampling frequency was 150 samples h-1. For the peak-width method, response was rectilinear for 50 µM to 0.1M; this method was particularly useful for routine determinations.
Penicillamine N Spectrophotometry Calibration Peak width

"Aqueous Flow Injection Analysis With Fourier Transform Infrared Detection"
Anal. Lett. 1985 Volume 18, Issue 16 Pages 1979-1998
Morgan, D.K.;Danielson, N.D.;Katon, J.E.

Abstract: A Barnes cylindrical internal reflection cell containing a zinc selenide crystal (diameter 0.318 cm) as internal reflector mounted in a stainless-steel high-pressure flow cell (25 µL) was used to connect a flow injection system with automated sample injection to a Digilab FTS-14C/D spectrometer with a coiled hot-wire source and a TGS detector. When the apparatus was used to determine Na dioctyl sulfosuccinate(I) in aqueous solution at 1234 or 1728 cm-1, the detection limit was 0.77 mg and coefficient of variation were 2 to 7% (n = 5) under stopped-flow conditions and were lower than those obtained in the flowing mode. The analyis rate was 25 samples per hour. The assembly was also used to analyze tablets containing I, capsules containing the Ca salt of I and aqueous solution of methicillin sodium.
Dioctylsulfosuccinate Spectrophotometry Stopped-flow

"Determination Of Some Tetracyclines By Spectrophotometry And Flow Injection Analysis"
Anal. Lett. 1992 Volume 25, Issue 10 Pages 1865-1876
Al Tamrah, S.A.;Alwarthan, A.A.

Abstract: Capsule contents (equivalent to 250 mg of tetracycline) were dissolved in water and the solution was diluted to 100 mL. Portions (200 µL) were analyzed by flow injection analysis in a manifold (described with diagram). Aqueous 1 mM sodium tungstate solution was mixed with a stream of 1 mM Na acetate buffer solution (pH 6). The sample solution were injected into the resulting stream and pumped (4.1 mL min-1) to a 25-cm reaction coil and then to the detector. Detection was at 380, 385 and 390 nm for oxytetracycline (I), doxycycline (II) and chlortetracycline (III), respectively. Calibration graphs were rectilinear from 1 µM (detection limit) to 10 mM I, II and III. A spectrophotometric method for the determination of some tetracyclines in bulk and pharmaceuticals is based on the reaction of the drug with sodium tungstate at pH 6 to form a yellow complex which can be determined spectrophotometrically. The complexes show absorption max. at 380, 385, and 390 nm for oxytetracycline, doxycycline, and chlortetracycline respectively.
Oxytetracycline Doxycycline Chlorotetracycline Spectrophotometry Buffer

"Determination Of Erythromycin In Tablets And Capsules Using Flow Injection Analysis With Chemiluminescence Detection"
J. Pharm. Biomed. Anal. 1989 Volume 7, Issue 11 Pages 1281-1285
Neil D. Danielson*, Li He, James B. Noffsinger and Letithia Trelli

Abstract: A flow injection system is described in which erythromycin in the carrier solution reacts at pH 6.0 with tris(bipyridine)ruthenium(III) in the low-volume detector cell, generating a product, the chemiluminescence of which is measured at 600 to 625 nm. The calibration graph is rectilinear from 3 to 24 µg mL-1. The coefficient of variation are 0.7 to 4.6% (n = 5). The method is suitable for combining with HPLC for determination of erythromycin in more complicated matrices.
Erythromycin Chemiluminescence HPLC

"Determination Of Penicillin In Pharmaceutical Formulations By Flow Injection Analysis Using An Optimised Immobilised Penicillinase Reactor And Iodometric Detection"
J. Pharm. Biomed. Anal. 1990 Volume 8, Issue 1 Pages 49-60
M. A. J. van Opstal, R. Wolters, J. S. Blauw, P. C. van Krimpen, W. P. van Bennekom and A. Bult

Abstract: An automated assay for the determination of penicillin in formulations suitable for use in pharmaceutical quality control is presented. The method is based on the classical iodometric penicillin assay which is incorporated in a flow injection analysis (FIA) system. The required hydrolysis is performed online by using an immobilized penicillinase reactor. Packed-bed and single-bead-string enzyme reactors are compared. It turns out that a packed-bed penicillinase reactor (10 cm x 1.5 mm i.d.) provides complete hydrolysis within short residence time, while only little back-pressure is generated. This enzyme reactor is stable for at least 9 months. Enzymatic hydrolysis of the β-lactam ring results in the formation of the corresponding penicilloic acid, which consumes iodine. The iodine consumption is determined colorimetrically by measuring the decrease of the absorbance of the blue colored iodine/starch complex. The optimum reactor length and flow rate for the colorimetrical detection reaction are determined. The optimized method is applied to the assay of penicillin in formulations and the results are compared with the 'true' results obtained with a reference method: a mercurimetric titration. The reliability of the flow injection method is evaluated quantitatively by determining the maximum total error (MTE). The reliability is shown to be highest when measuring at a 0.3-mM level. Eight formulations including capsules, tablets and injectables containing penicillin G, amoxicillin or flucloxacillin are assayed. The MTE does not exceed the 6% level and the most probable MTE is between 1.5 and 3.5%. A 30 µL portion of aqueous penicillin (I) solution was injected into a carrier stream (0.3 mL min-1) of 0.2 M potassium phosphate buffer (pH 6.5) and pumped into a packed-bed immobilized β-lactamase reactor (10 cm x 1.5 mm). The penicilloic acid formed was passed into a single-bead-string reactor (25 cm x 1.5 mm) and mixed with a reagent stream (0.7 mL min-1) of aqueous 0.15% starch solution - (0.5 mM I in 0.5 mM KI) - phosphate buffer (1:1:3). The decrease in absorbance of the blue iodine - starch complex was measured at 590 nm. The calibration graph was rectilinear from 0.1 to 0.5 mM I; the detection limit was 0.025 mM. Results compared well with those obtained by mercurimetric titration. Results are presented for the determination of I in eight formulations, including capsules, tablets and injectables.
Penicillin Spectrophotometry Optimization Immobilized enzyme Automation Enzyme Titrations Buffer pH Calibration Indirect Method comparison

"Automation Of Dissolution Testing Of Solid Oral Dosage Forms"
J. Pharm. Biomed. Anal. 1992 Volume 10, Issue 10-12 Pages 727-733
E. Lamparter* and Ch. Lunkenheimer

Abstract: An automated dissolution system (AUTO DISS) in which all operating steps are carried out synchronously is described. All steps from the filling of vessels with dissolution medium to cleaning and drying of vessels are controlled by a microcomputer. Up to 20 cycles can be tested in succession with six individual tablets per cycle. Online determination of active ingredient concentration. is possible with the aid of an integrated automatic sampler in combination with various measuring instruments such as UV - vis spectrometry, liquid chromatography or flow injection analysis. The suitability of the system was demonstrated by the dissolution and determination of brotizolam tablets and bepafant capsules using flow injection analysis and diode-array spectroscopy, respectively. Dissolution testing of solid oral dosage forms plays a very important part both in the development of new products and in quality control. A fully automated system for dissolution testing known as AUTO DISS is presented and its components are described. Online determination of active ingredient concentration is possible with the aid of an integrated automatic sampler in combination with various measuring instruments (UV-vis spectrometry, liquid chromatography and flow injection analysis). The suitability of the system is demonstrated by determination of the dissolution of brotizolam from tablets by FIA and of bepafant from capsules by diode-array spectroscopy.
Brotizolam Bepafant Spectrophotometry Process control Dissolution rate Automation

"Determination Of Disodium Clodronate In Bulk Material And Pharmaceuticals By Ion Chromatography With Post-column Derivatization"
J. Pharm. Biomed. Anal. 1992 Volume 10, Issue 10-12 Pages 881-887
Jussi P. Kosonen

Abstract: Portions (25 µL) of bulk materials, injectable preparations, tablets and capsules (prep. described) were analyzed by ion-chromatography, on a column (25 cm x 4 mm) of poly(styrene - divinylbenzene)copolymer (10 µm) in series with a guard column (5 cm x 4 mm) of IonPac AG7 with 40 mM HNO3 as mobile phase (0.5 mL min-1) and detection at 300 nm after post-column derivatization with acidic Fe(III) solution (0.25 mL min-1). Calibration graphs were rectilinear from 0.02 to 0.07 mg mL-1 of Na2 clodronate (I). Recoveries of I were 99.5 and 100.7% for capsule and tablet, respectively. The coefficient of variation (n = 6) were 0.8 to 1.3%.
Clodronate HPIC Spectrophotometry Post-column derivatization

"Flow Injection Spectrophotometric Determination Of Piroxicam"
J. Pharm. Biomed. Anal. 1993 Volume 11, Issue 10 Pages 933-938
C. Sánchez-Pedreño*, M. S. Garcia, M. I. Albero and J. Rodriguez

Abstract: Methanolic sample solution was injected into a carrier stream of methanol (1.2 ml/min) which merged with a stream of methanolic 0.1 M HCl and passed through a reaction coil (70 cm long) before detection at 332 nm. Alternatively, the carrier stream merged with a stream of methanolic 5 mM Fe(III); in this instance, detection was at 520 nm. Calibration graphs were linear for 0.15-15 and 30-500 µg/ml of piroxicam with use of detection at 332 and 520 nm, respectively; corresponding detection limits were 0.15 and 7.5 µg/ml. Recoveries were >98% for the two methods, and sample throughput was 90/h. The method was used to analyze suppositories, tablets, capsules, creams and ampoules. Two flow injection analysis (FIA) methods are proposed for the determination of piroxicam. The first involves measurement of the UV absorbance of a solution containing the drug, methanol and hydrochloric acid at 332 nm; in the second method a Fe(III)-piroxicam complex is formed in a methanolic medium and the absorbance is measured at 520 nm. In both methods, the peak height is used as a quantitative parameter and piroxicam is determined over the ranges 0.5-15 and 30-500 µg mL-1, respectively. The methods have been applied to the routine determination of the drug in dosage forms.
Piroxicam Spectrophotometry Complexation

"Determination Of Ampicillin Or Amoxycillin In Pharmaceutical Samples By Flow Injection Analysis"
J. Pharm. Biomed. Anal. 1994 Volume 12, Issue 12 Pages 1585-1589
M. S. García, C. Sánchez-Pedreño*, M. I. Albero and V. Ródenas

Abstract: Powdered capsule contents, suspensions or injection solutions equivalent to 37 mg of ampicillin (I) or 40 mg of amoxycillin (II) were dissolved in 1 mL of water (for I) or 1 mL of 1 M HCl (for II) and diluted to 100 mL with water. Portions (72 µL) were injected into a carrier stream (1.2 ml/min) of water which merged with a stream (1.2 ml/min) of 3 mM PdCl2 in 10 mM HCl before passing to a reactor (3 m x 0.5 mm i.d.) maintained at 40°C and on to a flow cell for detection at 400 nm. The calibration graphs for I and II were linear from 20 µM to 0.6 mM and the detection limits were 8 µM and 7.3 µM, respectively; the corresponding RSD were 0.16% and 0.22%. Recoveries were 99-102.2%. Sample throughput was 45/h. No interfering compounds were identified. The results agreed well those obtained by standard methods (European Pharmacopoeia Second Ed., Part II, volume 3, p. 260).
Ampicillin Amoxycillin Spectrophotometry Interferences Standard method Method comparison

"Flow Injection Spectrofluorimetric Determination Of Flufenamic And Mefenamic Acid In Pharmaceuticals"
J. Pharm. Biomed. Anal. 1995 Volume 13, Issue 9 Pages 1113-1117
M. I. Albero, C. Sanchez-Pedreño* and M. S. Garcia

Abstract: Capsule powder or suppositories equivalent to 250 mg mefenamic acid (I) were dissolved in 96% ethanol, filtered and the filtrate was diluted with ethanol. Cream was dissolved in ethanol. Portions (84 µL) were injected into a stream (1 ml/min) of ethanolic 3.7 mM Al(III), passed through a reactor (1.6 m x 0.5 mm i.d.) and the fluorescence was measured at 440 nm (excitation at 351 nm) for flufenamic acid (II) or at 454 nm (excitation at 355 nm) for I. The calibration graphs were linear for 0.02-1.2 and 0.3-16.1 µg/ml II and I, respectively, and the corresponding quantitation limits were 0.008 and 0.18 µg/ml. The RSD were 1.26% and 1.3%, respectively (n = 10); no interference was observed. Sample throughout was 90/h. The results agreed well with those obtained by the titrimetric British Pharmacopoeia method. Recoveries were 98-101%. Two sensitive and rapid flow injection (FI) spectrofluorimetric methods are proposed for the determination of flufenamic acid (FF) and mefenamic acid (MF), based on the formation of complexes of these compounds with A1(III) in an ethanolic medium. The calibration graphs resulting from the measurements of the fluorescence at lambda exc = 351 nm and lambda em = 440 nm, and lambdaexc = 355 nm and lambda em = 454 nm for the complexes with FF and MF, respectively, are linear over the range 0.030-1.20 µg mL-1 for FF and 0.30-16.1 µg mL-1 for MF. The methods have been applied to the determination of these drugs in pharmaceutical preparations.
Drugs Mefenamic acid Flufenamic acid Fluorescence Interferences Method comparison

"Flow Injection Analysis Of Pharmaceutical Compounds. 5. Quantitative Determination Of Stilboestrol Phosphate (fosfestrol) In Ampoules And Tablets"
Acta Pharm. Fenn. 1989 Volume 98, Issue 4 Pages 247-251
Abdel Moety, E.M.;El Khateeb, S.Z.

Abstract: Fosfestrol (5 to 30 µg mL-1) was determined at ~239 nm with water as carrier stream (2.2 mL min-1). The coefficient of variation (n = 6) were ~0.1 to 0.2%, and the sampling rate was ~140 h-1. The method was applied to ampoules and tablets. (For Part IV see Anal. Abstr., 1988, 50, 4E85).
Drugs Fosfestrol

"Determination Of Bromazepam By Flow Injection Analysis With Amperometric Detection"
An. Quim. 1988 Volume 84, Issue 1B Pages 120-122
Ruiz Zarobe, E.;Hernandez Blanco, M.;Lorenzo Abad, E.;Hernandez, L.

Abstract: Bromazepam (I) is determined by reduction at the vitreous-carbon electrode of a flow injection system. Thus, a solution with a I content of 6 to 32 µg mL-1 is injected into an eluent stream consisting of 0.1 M acetate buffer of pH 4.6 containing methanol (10% v/v), with a flow rate of 4 mL min-1 and amperometric detection. The method was used to determine I in capsules.
Bromazepam Amperometry Electrode

"Electrochemical Derivatization Of Thiamine In A Flow Injection System-application To Thiamine Analysis"
Chem. Pharm. Bull. 1983 Volume 31, Issue 10 Pages 3589-3594
Kusube, K.;Abe, K.;Hiroshima, O.;Ishiguro, Y.;Ishikawa, S.;Hoshida, H.

Abstract: The method is based on electrochemical oxidation of thiamine to thiochrome. A flow-through electrolytic cell, consisting of a vitreous-carbon tube (10 cm x 5 mm) as working electrode and a vitreous-carbon rod (15 cm x 3 mm) as counter-electrode, is described and illustrated. For determination of thiamine, the sample (10 µg mL-1 in methanol) was injected into a flow (0.5 mL min-1) of aqueous 90% methanol 0.05 M in NaClO4 and containing 1% NaOH, and a potential of +0.4 V was applied vs. silver - AgCl. Detection was by fluorimetry at 430 nm, with excitation at 375 nm. The calibration graph was rectilinear for 1 to 100 ng of thiamine and the time required was 3 min for each determination. The results for analysis of a vitamin capsule, a tablet and a syrup were in good agreement with those obtained by a chemically induced fluorimetric and a HPLC method, without interference from other B-group vitamins or a number of other vitamins.
Thiamine Electrode Fluorescence Potentiometry Interferences

"Automated Dissolution Testing With Flow Injection Analysis. Dissolution Profiles For The Antiviral Drugs, DHPG And Acyclovir, In Capsule Formulations"
Drug Dev. Ind. Pharm. 1987 Volume 13, Issue 1 Pages 39-56
Richard A. Kenley, Stuart E. Jackson, Gary C. Visor, and John S. Winterle

Abstract: We have designed, assembled, and tested an automatic dissolution apparatus using flow-injection analysis (FIA) techniques with spectrophotometric detection. The components (pumps, switching valves, detector, and so forth) that comprise the system are all readily-available items used primarily for high-performance liquid chromatography. The system performs well as evidenced by the usual tests for precision, response linearity, and dissolution behavior of standard U.S.P. calibrator (salicylic acid and prednisone) tablets, and offers siqnificant advantages over conventional continuous-flow dissolution testing methods with respect to simplicity, cost, and versatility. Dissolution tests on capsules of the antiviral drugs, DHPG and acyclovir, showed very similar drug release profiles for both formulations.
Drugs DHPG Acyclovir Spectrophotometry Dissolution rate

"A Study On The Micelle-sensitized Ce(IV)-Na2S2O3-norfloxacin Chemiluminescence System And Its Applications"
Luminescence 2005 Volume 20, Issue 3 Pages 220-225
Zenghong Xie, Sulan Liao, Guonan Chen*

Abstract: A new chemiluminescence (CL) flow-injection method was developed for the determination of norfloxacin. The method is based on the CL reaction of norfloxacin with sodium thiosulphate and Ce(IV) in sulphuric acid medium sensitized by sodium dodecylsulphate. Under optimum conditions, the CL intensity is proportional to the concentration of the norfloxacin in the range 3.89 x 10^-8-7.18 x 10^-6 g/mL. The detection limit (3 s[sol ]k) was 2.21 x 10^-9 g[sol ]mL for norfloxacin. The method has been applied successfully to the determination of norfloxacin in pharmaceutical formulations and human urine. The mechanism for this chemiluminescence system is discussed.
Norfloxacin Chemiluminescence Optimization Micelle

"Determination Of Azapropazone In Its Pharmaceutical Form By HPLC And Flow Injection Analysis"
J. Liq. Chromatogr. Relat. Technol. 2005 Volume 28, Issue 6 Pages 857-869
Nafiz Oncu Can and Goksel Altiokka

Abstract: Azapropazone is an analgesic and anti-inflammatory agent that is used in the treatment of musculoskeletal and joint disorders, as well as in acute gout, because of its uricosuric properties. A simple and sensitive high performance liquid chromatographic method (HPLC), for the determination of azapropazone in its pharmaceutical form has been developed and validated. Azapropazone and indapamide (internal standard) were separated by a reversed phase column (Supelco Hypersil 5 µm, 150 x 4.6 mm ID, C18) with a mobile phase consisting of K2HPO4 (0.1 M) and methanol (55:45, v/v) (at pH 7.0). The mobile phase was pumped at 1.2 mL min-1 flow rate then azapropazone was determined by ultraviolet detection at 251 nm. The method has an average analysis time of 5.81 min. for azapropazone. The flow injection analysis (FIA) was performed by using a carrier stream of ethanol:water (10:90, v/v) with a flow rate of 1.2 mL min-1. The LOD and LOQ concentrations of azapropazone for the two methods were 2.77 x 10^-8 M and 8.41 x 10^-8 M for HPLC, 3.65 x 10^-7 M and 1.10 x 10^-6 M for FIA, respectively. The results obtained from the analysis of capsule samples using both methods were compared by common statistical tests. There was no significant difference observed between the methods.
Azapropazone Spectrophotometry Method comparison