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
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International Journal of Pharmaceutics

  • Publisher: Elsevier
  • FAD Code: IJPH
  • CODEN: IJPHDE
  • ISSN: 0378-5173
  • Abbreviation: Int. J. Pharm.
  • DOI Prefix: 10.1016/j.ijpharm,10.1016/S0378-5173
  • Language: English
  • Comments: Fulltext from 1978 V1

Citations 10

"A Flow Injection Analysis/mass Spectrometry Method For The Quantification Of Polyethylene Glycol 300 In Drug Formulations"
Int. J. Pharm. 2004 Volume 282, Issue 1-2 Pages 183-187
Jun Zhang, Jenny Lin and Timothy A. Anderson

Abstract: A direct flow injection analysis/mass spectrometry (FIA/MS) method was developed for the quantification of polyethylene glycol. The method was used for the evaluation of distribution uniformity and mixing homogeneity of polyethylene glycol 300 (PEG 300) as a component in drug formulation mixtures. In the method, five of the most intense ions of the PEG 300 oligomer were chosen for selected ion monitoring (SIM) by mass spectrometry. Standard calibration curves were established, using either single channel SIM or the summed intensity of all five SIM channels plotting against the standard concentrations. Both calibration approaches produced comparable results on quantification. The feasibility of the method was demonstrated using both atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI). The method provided fast and sensitive quantification of PEG 300 without tedious chromatographic separation or sample preparation. The method has been successfully adopted for the evaluation of the mixing process in drug formulations.

"Flow Injection Potentiometric Determination Of Bismuth(III) In Anti-acid Formulations"
Int. J. Pharm. 2001 Volume 221, Issue 1-2 Pages 115-121
Marcos F. S. Teixeira and Orlando Fatibello-Filho

Abstract: A flow injection potentiometric procedure is proposed for determining bismuth(III) in anti-acid formulations. In this work, a tubular electrode coated with an ion-pair formed between [Bi(EDTA)]- and tricaprylylmethylammonium cation (Aliquat 336) in a poly(vinylchloride) (PVC) was constructed and used in a single channel flow injection system. The effect of membrane composition, pH and flow injection parameter over the Bi(III) tubular electrode response (slope (mV/decade)) was initially evaluated in quintuplicate in 0.5 mol L-1 EDTA solution as carrier. The best response (-59.6±0.9 mV/decade) was attained with the 5% m/m ion-pair; 65% m/m o-nitrophenyl octyl ether (o-NPOE) and 30% m/m PVC in pH 6-9. The electrode showed a linear response to E (mV) versus log [Bi(EDTA)]- in the bismuth(III) concentration range from 2.0 x 10^-5 to 1.0 x 10^-2 mol L-1 and a useful lifetime of at least 5 months (more than 1000 determinations for each polymeric membrane). The detection limit was 1.2 x 10^-5 mol L-1 and the RSD was less than 2.0% for a solution containing 5.0 x 10^-4 mol L-1 bismuth(III) (n=10). Several species such as Cd(II), Mn(II), Ni(II), Zn(II), Co(II), Cu(II), Mg(II), Cr(III) and Al(III) at 1.0 x 10^-3 mol L-1 concentration in 0.5 mol L-1 EDTA solution did not cause any interference. The frequency rate was 90 determinations per hour and the results obtained for bismuth(III) in anti-acid formulations using this flow procedure and those obtained using a spectrophotometric procedure are in agreement at the 95% confidence level.

"Flow-through UV Spectrophotometric Sensor For Determination Of (acetyl)salicylic Acid In Pharmaceutical Preparations"
Int. J. Pharm. 2001 Volume 216, Issue 1-2 Pages 95-104
Antonio Ruiz-Medina, Maria L. Fernández-de Córdova, Pilar Ortega-Barrales and Antonio Molina-Díaz

Abstract: The solid phase spectrophotometry technique. in which the absorbance of the species of interest sorbed on a solid support is measured directly, was applied to the determination of salicylic acid using flow injection-analysis. Salicylic acid was determined by monitoring of its intrinsic absorbance at 297 nm sorbed on Sephadex QAE A-5 resin placed in an appropriate Row-through cell, The method proposed improves the selectivity compared with the corresponding solution-phase method and the sensitivity is increased by a factor of 30 or more. The flow-through sensor proposed allows working with several calibration lints simply by varying the sample volume injected. Thus, linear dynamic ranges from 1 to 20 and From 2 to 40 µg mL-1 can be obtained by using 1000 and 300 µL. respectively, with detection limits being 0.064 and 0.135 µg mL-1. Relative Standard Deviations (RSDs) of 0.52 and 0.38%. and sampling frequencies of 18 and 25 hr-1, respectively. were also achieved. The sensor also allows the indirect determination of acetylsalicylic acid previous hydrolysis on-line to salicylic acid. For acetylsalicylic acid, a linear dynamic range from 5 to 120 µg mL-1 and 25 h-1 of sampling frequency (300 µL of sample volume) M ere obtained. The proposed Row-through sensor has been successfully applied to the determination of both analytes in pharmaceutical preparations. (C) 2001 Elsevier Science B.V. All rights reserved.

"Selective Determination Of Pyridoxine In The Presence Of Hydrosoluble Vitamins Using A Continuous-flow Solid Phase Sensing Device With UV Detection"
Int. J. Pharm. 2000 Volume 202, Issue 1-2 Pages 113-120
M. J. Ayora Cañada, M. I. Pascual Reguera and A. Molina Díaz

Abstract: A very simple, inexpensive and highly selective flow injection UV spectrophotometric method for the determination of vitamin B-6 is presented. The native absorbance of the analyte is continuously monitored at 290 nm when it is transiently retained on Sephadex SP C-25 cation exchanger gel beads placed in the detection area of a flow cell. The pre-concentration on the active solid phase provides by itself a high increase in sensitivity compared with the same procedure carried out without a solid support. The analytical response is linear in the concentration ranges 1-10 and 2-20 µg mL-1 using 600 and 1250 µl of sample, respectively. The R.S,D. (%) are 0.65 (600 µl) and 0.84 (1250 µl) and the detection limits 0.08 and 0.02 µg mL-1, respectively. The procedure was successfully applied to the determination of vitamin B-6 in pharmaceuticals containing (among other active principles) hydrosoluble vitamins in much higher concentrations than that tolerated by the method if performed in aqueous solution. Nevertheless they were tolerated using the proposed sensor due to the selective retention of the analyte.

"Dissolution Of Four Controlled-release Theophylline Formulations In Milk"
Int. J. Pharm. 1987 Volume 36, Issue 1 Pages 73-80
P. Macherasa*, M. Koupparis* and E. Apostolellia

Abstract: The dissolution of 4 controlled-release theophylline formulations was studied in a low-fat (0.75%) milk and in a buffer of pH 6.5. A flow injection dialysis-UV spectrophotometric method was developed to determine the drug in the milk samples. Calibration curves were linear up to 250 µg/ml for theophylline and aminophylline and up to 450 µg/ml for choline theophyllinate, with detection limits of 18.5, 5.4, and 14.7 µg/ml, respectively, in a 5.0 mL minimum sample volume. Lower dissolution profiles in milk than in buffer were observed for 3 of the formulations examined. One theophylline formulation exhibited relatively similar dissolution profiles in both media. The use of milk as a food-stimulating medium in dissolution studies is suggested for the in vitro evaluation of the release drugs from controlled release-formulations. The proposed technique can be applied in such studies.
Theophylline Milk Pharmaceutical Spectrophotometry Dissolution rate Dialysis

"Drug Dissolution Studies In Milk Using The Automated Flow Injection Serial Dynamic Dialysis Technique"
Int. J. Pharm. 1986 Volume 33, Issue 1-3 Pages 125-136
P. Macherasa,*, M. Koupparisb,* and C. Tsaprounisa

Abstract: The application of flow injection serial dynamic dialysis (FISDD) technique to monitor dissolution studies in complex media is described. The method is based on the study of the kinetics of the simultaneous dissolution and dialysis processes. Commercial formulations of salicylamide, propantheline bromide, nitrofurantoin and acetaminophen were used to investigate the utility of the FISDD technique for studying the dissolution of drugs in low fat milk. The latter was utilized as a food simulating medium. Dissolution studies were also conducted in phosphate buffer of pH 6.5. In each case the FISDD system was coupled with the rotating basket apparatus. The determination of the dialyzable drugs was performed automatically by the FIA analyzer. A fully automated monitoring of dissolution of drugs in milk and buffer was achieved. In all cases the dissolution rate of drugs in milk was lower than the corresponding rate in the aqueous buffer. The potential significance of this system with respect to the in vitro study of dissolution of drugs in food simulating media is discussed. This system could be used either to reveal or explore food-drug and/or food-formulation interactions anticipated or observed in vivo.
Drugs Milk Dialysis Dissolution rate

"Automated Flow Injection Serial Dynamic Dialysis Technique For Drug-protein Binding Studies"
Int. J. Pharm. 1986 Volume 30, Issue 2-3 Pages 123-132
P. Macheras,*, M. Koupparis,* and C. Tsaprounis

Abstract: The interface of an automated flow injection analyzer with a dialysis unit to study drug-protein interactions using flow injection serial dynamic dialysis (FISDD) procedure is described. The method is based on the study of the kinetics of dialysis of the ligand in the absence and presence of protein. A study of the binding of sulfamethoxazole. sulfamethizole and sulfisoxazole to bovine serum albumin by means of such an automated system was undertaken to investigate the utility of FISDD technique for protein binding studies. The determination of dialysable sulfonamides was performed automatically by the FIA analyzer.. The influence of ionic strength and viscosity on the rate of dialysis was investigated. It was found that both variables did not affect the kinetic profile. Binding by the cellophane membrane was not encountered as a problem with the compounds studied. Binding parameters estimated for sulfamethoxazole were found to agree well with those reported in the literature. The Scatchard plots for the binding of sulfamethizole and sulfisoxazole with bovine serum albumin, revealed two classes of binding sites for each sulfonamide. The system was also used for the calculation of the dialytic rate constants. Experimental variables can be readily controlled to yield favoured conditions to study the protein binding phenomenon.
Drugs Sulfonamides Spectrophotometry Dialysis

"Automated Flow Injection Colorimetric Determination Of Acetaminophen For Assays And Dissolution Studies Of Multicomponent Dosage Forms"
Int. J. Pharm. 1985 Volume 27, Issue 2-3 Pages 349-359
M. Koupparis,*, P. Macheras and C. Tsaprounis

Abstract: An automated flow-injection determination of acetaminophen, based on its oxidation with iron(III) and subsequent chelation of the produced iron(II) with 2,4,6-tripyridyl-S-triazine (TPTZ), is described. Acetaminophen in the range 50-500 µg/ml can be rapidly determined with a precision of 0.4% with a rate of 120 measurements per hour. Salicylates and phenothiazines interfere seriously. The method was evaluated by performing recovery studies and analyzing commercial formulations. The method was also used to monitor the dissolution of acetaminophen formulations. Full automation of the dissolution studies was achieved. A complete dissolution profile in tabulated form and graphical presentation were provided at the end of the study. Results obtained by the proposed method were found to agree well with those derived from established techniques.
Acetaminophen Pharmaceutical Spectrophotometry

"Application Of Automated Flow Injection Analysis To Dissolution Studies"
Int. J. Pharm. 1984 Volume 20, Issue 3 Pages 325-333
M. Koupparis, P. Macheras* and C. Reppas

Abstract: The application of FIA to dissolution studies is described. Propantheline bromide, salicylamide and sulfamethizole were chosen as model drugs to investigate the utility of FIA method for dissolution studies. In each case the FIA system with the appropriate chemistry manifold was coupled with the rotating basket apparatus, A fully automated monitoring of dissolution rates was achieved. A complete dissolution profile in tabulated form is provided by the computer of the system at the end of the experiment.

Automation of any type of solid dosage forms agitation technique can be easily acquired by adapting a FIA system.

Propantheline bromide Salicylamide Sulfamethizole Pharmaceutical Clinical analysis Spectrophotometry

"Amperometric Determination Of Guanethidine Sulfate In A Flowing Stream At The Glassy Carbon Electrode"
Int. J. Pharm. 1984 Volume 20, Issue 1-2 Pages 65-72
James T. Stewart* and Mumtaz H. Shah

Abstract: A flow injection method for the determination of guanethidine sulfate (an antihypertensive agent) based on electrochemical oxidation at the glassy carbon electrode is presented. The amperometric method may be used to determine guanethidine sulfate in the presence of other drugs commonly found in its pharmaceutical dosage forms or administered concurrently in therapeutic situations. Using an electrode potential of +1200 mV, a calibration curve is linear in the 0.5-16 µg/ml concentration range with minimum detectability at 5 ng (S/N (signal-to-noise ratio) = 2). The method applied to the analysis of guanethidine sulfate in selected pharmaceutical dosage forms shows good accuracy and precision. Although automation was not used in this study, the method could readily be incorporated in automated systems because it employs the technique of continuous analysis in a flowing stream.
Guanethidine sulfate Pharmaceutical Amperometry Electrode