Automatic potentiometric flow titration procedure for ascorbic acid determination in pharmaceutical formulations

Paim, Ana Paula S.; Almeida, Cristina M.N.V.; Reis, Boaventura F.; Lapa, Rui A. S.; Zagatto, Elias A.G.; Lima, José L.F.C.

doi:10.1016/s0731-7085(02)00018-3

Cited by 28 publications

(17 citation statements)

References 21 publications

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“…An RNA isolation kit was purchased from QIAGEN (Valencia, CA). The PKC inhibitor GF109203X, paclitaxel (for drug safety monitoring, paclitaxel is widely used in the treatment of lung, ovarian, and breast carcinomas (Mekhail and Markman, 2002) and the first of a new class of microtubule stabilizing agents, has been hailed by National Cancer Institute (NCI) as the most significant advance in chemotherapy of the past 15-20 years (Paim et al, 2002)), vincristine, irinotecan, dimethyl sulfoxide (DMSO), 3-(4,5-dimethyl thizol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), b-actin monoclonal antibodies, and horseradish peroxidase (HRP)-conjugated secondary antibodies were purchased from Sigma (St Louis, MO). The ERK1/2 kinase inhibitor PD98059 and PI3K/AKT inhibitor LY294002 were purchased from Calbiochem (San Diego, CA).…”

Section: Chemicals and Reagentsmentioning

confidence: 99%

Synergistic anti‐tumor activity of isochaihulactone and paclitaxel on human lung cancer cells

Chen

et al. 2011

Journal Cellular Physiology

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Drug resistance frequently develops in tumors during chemotherapy. Therefore, to improve the clinical outcome, more effective and tolerable combination treatment strategies are needed. Here, we show that isochaihulactone (K8) enhanced paclitaxel-induced apoptotic death in human lung cancer cells, and the enhancing effect was related to increased NSAID-activated gene-1 (NAG-1) expression. CalcuSyn software was used to evaluate the synergistic interaction of K8 and paclitaxel on human lung cancer cells; the synergistic effect of K8 in combination with paclitaxel was increased more than either of these drugs alone. Furthermore, the activity of ERK1/2 was enhanced by the combination of K8 and paclitaxel, and an ERK1/2 inhibitor dramatically inhibited NAG-1 expression in human lung cancer cells. Therefore, this synergistic apoptotic effect in human lung cancer cells may be directly associated with K8-induced NAG-1 expression through ERK1/2 activation. Moreover, over-expression of NAG-1 enhanced K8/paclitaxel-induced apoptosis in human lung cancer cells. In addition, treatment of nude mice with K8 combined with paclitaxel induced phospho-ERK1/2 and NAG-1 expression in vivo. Targeting of NAG-1 signaling could enhance therapeutic efficacy in lung cancer. Our results reveal that activation of NAG-1 by K8 enhanced the therapeutic efficacy of paclitaxel in human lung cancer cells via the ERK1/2 signaling pathway.

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Section: Chemicals and Reagentsmentioning

confidence: 99%

Synergistic anti‐tumor activity of isochaihulactone and paclitaxel on human lung cancer cells

Chen

et al. 2011

Journal Cellular Physiology

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“…Titration is a quantitative analysis method used to determine the concentration of many active pharmaceutical ingredients such as tetraphenylborate sodium, phenothiazine compounds, acetaminophen, captopril, ascorbic acid, albendozole, sparfloxacin, salbutamol sulfate, montelukast sodium, phenylephrine hydrochloride, candesartan cilexetil [7][8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Status of Hydrogen Peroxide Solution 10 V in Commercialized Samples

Mn¹,

Ac²,

Hrn³

2017

Pharm Anal Acta

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Hydrogen peroxide (H 2 O 2 ) is one of the most powerful oxidants used in many sectors. Analytical method such as titration by permanganometry is used to maintain the quality of products containing H 2 O 2 . Thus, the objective of this work was to evaluate commercial samples of H 2 O 2 10 V by permanganometry. A difference of almost 3 volumes was found in the analysis of the samples. These results can be real or assigned to the potassium permanganate solution, not automation of the results and/or instability of the H 2 O 2 solutions, for example. The main issue is, in addition to alerting the consumers to adequate storage of H 2 O 2 solutions, to alert the scientific community to the need for concomitant analysis methods for unstable products such as H 2 O 2 10 V solutions in order to avoid doubts on the results and make the manufacturers aware of these quality tests.

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“…3 The potentiometric method for ascorbic acid determination has been described with sensitivity from 7.5 to 15 mmol/L. 4 The electrochemical method for ascorbic acid determination has been proposed; the calibration curve was linear up to 5 mmol/L, with the detection limit of 2.5·10 -4 mmol, and an RSD better than 2.8%. 5 Visible spectrophotometric methods 6,7 have been developed for the determination of ascorbic acid in pharmaceutical samples, and it has also been determined by direct ultraviolet spectrophotometry 8 using thermal decomposition at 90°C to the destroy ascorbic acid as a means of correcting for background absorption.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Spectrophotometric Determination of Ascorbic Acid in Pharmaceutical Samples by Oxidation of Ponceau 4R by Hydrogen Peroxide

Grahovac

Mitić

Pecev

et al. 2008

J Chinese Chemical Soc

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A new sensitive and simple kinetic method is developed for determination of traces of ascorbic acid based on its activated effect on oxidation of trisodium-2-hydroxy-1-(4-sulphonato-1-naphthylazo)naphthalene-6,8-disulphonato (red artificial color Ponceau 4R) by hydrogen peroxide, in the presence of Cu(II) as catalyst, in borate buffer. The reaction is followed spectrophotometrically by tracing the oxidation product at 478.4 nm within 1 min after addition of H 2 O 2 . The optimum reaction conditions are: borate buffer (pH = 11.00), Ponceau 4R (9.6·10 -6 mol/L), H 2 O 2 (2·10 -2 mol/L), Cu(II) (8·10 -7 mol/L) at 22°C. Following this procedure, ascorbic acid can be determined with a linear calibration graph up to 1.76 ng/mL and a detection limit of 0.28, based on 3S criterion. The relative error ranges between 6.77-1.66% for the concentration interval of ascorbic acid 1.76-17.61 ng/mL. The effects of certain foreign ions upon the reaction rate were determined for an assessment of the selectivity of the method. The method was applied for determination of ascorbic acid in pharmaceutical samples, and spectrophotometric method was used like an comparative method.

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Automatic potentiometric flow titration procedure for ascorbic acid determination in pharmaceutical formulations

Cited by 28 publications

References 21 publications

Synergistic anti‐tumor activity of isochaihulactone and paclitaxel on human lung cancer cells

Synergistic anti‐tumor activity of isochaihulactone and paclitaxel on human lung cancer cells

Status of Hydrogen Peroxide Solution 10 V in Commercialized Samples

Kinetic Spectrophotometric Determination of Ascorbic Acid in Pharmaceutical Samples by Oxidation of Ponceau 4R by Hydrogen Peroxide

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