High Performance Liquid Chromatographic Determination of Pirenzepine Dihydrochloride in Its Pharmaceutical Formulation

Abstract

A high-performance liquid chromatographic procedure for the determination of pirenzepine dihydrochloride as a bulk material and in its tablet dosage form (Gastrozepin^R) is presented. Normal phase liquid chromatography has been performed on a Micro-pack Si-10 column using ammonium hydroxide (28–30% NH₃) in methanol (0.75: 99.25% v/v) as mobile phase at a flow rate of 2 ml/min. Clobazam has been used as internal standard with retention times of 1.9 and 2.8 minutes for clobazam and pirenzepine dihydrochloride, respectively at 254 nm. Analytical calibration yields a linear relationship between 5 and 25 μg/ml, with correlation coefficient of 0.999. Tablets each labelled to contain 25 mg pirenzepine dihydrochloride give mean percentage found of 99.98 ± 0.4. A plot of logarithm of concentration against time for a solution in 6 N hydrochloric acid gives a straight line with a slope of - 0.197 day^?1. The proposed method is, therefore, a stability indicating method.     

Spectrophotometric Analysis of some Phenothiazine Neuroleptics using Chloramine-T

ABSTRACT

A sensitive and selective spectrophotometric method has been developed for the determination of six phenothiazine neuroleptics. The method is based on the interaction of the drugs with chloramine-T in sulphuric acid medium to yield a red, reddish-violet, orange or greenish-blue intermediate with maximum absorption at 500-636 nm. Beer's law is obeyed over the range 5-125 μg ml^?1 of the drugs. The apparent molar absorptivities were found to be in the range 1.04x10³ to 5.46x10³ 1.mol^?1cm^?1. The investigated drugs were assayed in tablets and injections. The mean percentage recoveries were 97.65-101.75 and the relative standard deviations were found to be less than 2%.     

Spectrophotometric Determination of Certain Phenothiazines and Their Dosage Forms Using Bromophenol Blue

Abstract

A simple and rapid spectrophotometric method for the determination of seven phenothiazine derivatives has been performed either in pure form or in their dosage forms. The method is based upon the interaction of the drug in dry chloroform with bromophenol blue in the same solvent to produce a stable yellow ion-pair complex which absorbs at 410 nm, with high apparent molar absorptivity. Beer's Law is obeyed in the concentration range 1?10 ugml^?1 for the studied compounds. The mean recoveries range from 99.80±0.74 to 100.50±1.33. The proposed method is applied for the analysis of the studied compounds in their commercial preparations. Results are in good agreement with those obtained by official methods.     

Preparation and Thermal Decomposition of Cyclic Azoamidinium Salts as Water-Soluble Radical Initiators for Polymerization over A Wide Temperature Range

Abstract

A series of cyclic azoamidinium chlorides as water-soluble initiators were prepared by reactions of the iminoether derived from 2,2′-azobisisobutyronitrile with substituted alkylene diamines. The first-order rate constants for the decomposition of the azoamidinium salts varied from 0.59 × 10^?5 to 14.1 × 10^?5 s^?1 with the ring size and the alkyl substitution of the ring. Decomposition of 2,2′-azobis[2-(imidazoline-2-yl)propane] dihydrochloride was found to be accelerated by alkyl substitution on the imidazolinium ring. However, the azoamidinium compounds having larger rings, 2,2′-azobis[2-(3,4,5-trihydropyrimi-dine-2-yl)propane] dihydrochloride and 2,2′-azobis[2-(4,5,6,7-tetra-hydro-1H-1,3-diazepine-2-yl)propane] dihydrochloride, decomposed at a slower rate than the unsubstituted azobis[2-(imidazoline-2-yl)-propane] dihydrochloride. These new initiators were found to be capable of initiating radical polymerizations of acrylamide and vinyl acetate.     

Simultaneous Determination of Caffeine and Meclizine Dihydrochloride in Sugar-Coated Tablets

Abstract

In this study, simultaneous determination of caffeine and meclizine dihydrochloride in their binary mixture was conducted by two spectrophotometric methods. In the first method, derivative spectrophotometry, the quantification of caffeine and meclizine dihydrochloride was performed by reading the dA/dλ values at 286.2 nm and 243.4 nm respectively in the first derivative spectra of their mixture in methanol. The relative standard deviation of the method was 0.54% for caffeine and 0.67% for meclizine dihydrochloride. In the second, selective precipitation + derivative spectrophotometry, determination of meclizine dihydrochloride was carried out by precipitation with potassium ferricyanide at pH 2 selectively, then measuring the absorbance of its solution in methanol at 420.8 nm, and determination of caffeine was succeeded by reading the dA/dλ values at 260.6 nm in the first derivative spectra of the remaining solution after precipitation. Relative standard deviation of the method was found to be 0.56% for caffeine and 1.85% for meclizine dihydrochloride. These two methods were applied successfully to a sugar-coated tablet containing these drugs.     

Spectrophotometric determination of some phenothiazine drugs using chloramine-T-iodine-starch

A simple, accurate, and sensitive spectrophotometric method for the determination of promethazine hydrochloride (PMH), prochlorperazine maleate (PCPM), trifluoperazine hydrochloride (TFPH), trimeperazine tartrate (TMT), fluphenazine dihydrochloride (FH), and trifluopromazine hydrochloride (TPH) is described. The method is based on the oxidation of the studied drugs by a known excess of chloramine-T in a hydrochloric acid medium and subsequent determination of the unreacted oxidant by interacting it with iodide in the same acid medium. Liberated iodine subsequently reacts with starch to form a stable starch-iodine complex. The reacted oxidant corresponds to the drug content. The colored complex exhibits a maximum absorption at 590 nm. The apparent molar absorptivity and Sandell sensitivity values are in the range 4.07 × 10⁴ − 1.18 × 10⁵ L/mol cm and 45.00−95.00 ng/cm², respectively. The proposed method has been applied to the assay of phenothiazine drugs in pure and dosage forms. The reliability of the analysis was established using parallel determination by the reference method. The text was submitted by the authors in English.     

Determination of Some Phenothiazine Drugs Based on Colour Reaction with Potassium Periodate

ABSTRACT

A simple, rapid and sensitive method for the determination of six phenothiazine drugs, either in pure form or in pharmaceutical formulations, is described. The method is based on the formation of stable phenothiazine free radical by the use of potassium periodate as the chromogenic reagent in sulphuric acid medium. The reaction is suggested to proceed via oxidation of the phenothiazine nucleus into a semiquinonoid radical. The wavelengths of maximum absorption range from 500 to 525nm. Molar absorptivities range from     

Side‐chain effects on phenothiazine‐based donor–acceptor copolymer properties in organic photovoltaic devices

A series of new phenothiazine‐based donor–acceptor copolymers, P1 and P2, were synthesized via a Suzuki coupling reaction. The weight‐averaged molecular weights (M_w) of P1 and P2 were found to be 16,700 and 16,100, with polydispersity indices of 1.74 and 1.39, respectively. The UV–visible absorption spectra of the polymer thin films contained three strong absorption bands in the ranges 318–320 nm, 430–436 nm, and 527–568 nm. The absorption peaks at 320 and 430 nm originated mainly from the phenothiazine‐based monomer units, and the longer wavelength absorption band at 527–568 nm was attributed to the increased effective conjugation length of the polymer backbones. Solution‐processed field‐effect transistors fabricated with these polymers exhibited p‐type organic thin film transistor characteristics. The field‐effect mobilities of P1 and P2 were measured to be 1.0 × 10^?4 and 7.5 × 10^?5 cm² V^?1 s^?1, respectively, with on/off ratios in the order of 10⁴ for all polymers. A photovoltaic device in which a P2/PC₇₁BM (1/3) blend film was used as the active layer exhibited an open‐circuit voltage (V_OC) of 0.70 V, a short‐circuit current (J_SC) of 6.79 mA cm⁽², a fill factor of 0.39, and a power conversion efficiency of 1.86% under AM 1.5 G (100 mW cm^?2) illumination. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and characterization of low‐band‐gap conjugated polymers containing phenothiazine and benzo‐2,1,3‐thia‐/seleno‐diazole

Two phenothiazine‐based conjugated polymers, poly(3, 7‐divinylene‐N‐octyl‐phenothiazine‐alt‐benzo‐2,1,3‐ thiadiazole) (PQS) and poly(3,7‐divinylene‐N‐octyl‐phenothiazine‐alt‐benzo‐2,1,3‐selenodiazole) (PQSe) were synthesized by Heck coupling reaction. The chemical structures of the two polymers were confirmed by ¹H‐NMR and Ft‐IR. They showed good solubility in some common organic solvents such as tetrahydrofuran (THF), chloroform. The weight‐average molecular weight (Mw) of the polymers determined by GPC in THF against polystyrene standards was 3.7 × 10³ for PQS and 1.9 × 10³ for PQSe, respectively. The temperatures of 5% weight loss (T₅) were 385.0°C for PQS and 324.0°C for PQSe, respectively, determined by TGA measurements under nitrogen ambience. UV–vis absorption spectra of the polymer films showed the absorption maxima at 537 nm for PQS and 539 nm for PQSe, with the full width at half maximum (FWHM) of 190 and 230 nm, respectively. The optical band gaps ( ) of the polymer films are 1.86 eV for PQS and 1.80 eV for PQSe, respectively. As the polymers have low‐band‐gap and broad absorption in the visible region, they may be used as potential light‐harvesting materials for photovoltaic devices (PVDs). Furthermore, photoluminescence (PL) spectra of the polymer solutions showed the emission maxima at 698 nm for PQS and 709 nm for PQSe, with FWHM of 152 nm and 167 nm, respectively, which revealed that these two polymers may be used as red and near infrared light‐emitting materials for polymeric light‐emitting diodes (PLEDs). Copyright © 2009 John Wiley & Sons, Ltd.     

Spectrophotometeric determination of someN-substituted phenothiazine derivatives usingN-bromophthalimide

A simple, rapid and sensitive spectrophotometric method is described for the quantitative determination ofN-substituted phenothiazines. The method depends on the formation of a stable phenothiazine free radical cation by the use ofN-bromophthalimide as oxidising agent in a strong acid medium (methanol/ sulphuric acid 1 1 v/v). The produced red or violet color possesses absorption maximum range from 500 to 530 nm. A linear relationship exists between the absorbance at (_max) and concentration in the range 5 to 40 g ml^–1 with apparent molar absorptivities range from 6 × 10³ to 12 × 10³1 mol^–1 cm^–1. The color is developed instantaneously for all the studied phenothiazines except for thioproperazine mesylate, trifluoperazine dihydrochloride and prochlorperazine mesylate that require 25, 15 and 25 min, respectively, for complete reaction. The developed colors are stable over 24 h. The average % recovery is 99.85±0.61 to 100.28±0.95. The method was applied successfully to the microdetermination of chlorpromazine HCl, promethazine HCl, pericyazine, thioproperazine mesylate, perphenazine, prochlorperazine mesylate, trimeprazine tartrate and trifluoperazine 2HCl either in pure form or incorporated in their pharmaceutical preparations. The results of analysis are in good agreement with those of the official B.P. 1988 and USP XXII.     

Spectrophotometric Determination of Hydrazine

Abstract

A simple sensitive and selective method is described for the determination of trace amounts of hydrazine. The method is based on the reduction of nitrate to nitrite. Hydrazine in ammoniacal condition is used as reducing agent with copper(II) as catalyst. The nitrite prepared is determined based on the diazo coupling reaction between p‐nitroaniline and N‐(1‐naphthyl)ethylenediammine dihydrochloride(NEDA). The method obeys Beer's law in the concentration range of 0–15 µg of hydrazine in a sample volume of 10 ml at 545 nm and the colour is stable for 3 h. The molar absorptivity is calculated to be 3.83×10⁴ l/mol/cm with a correlation coefficient of 0.999. The relative standard deviation is 1.8% (n=10) at 12 µg of hydrazine. Interferences due to foreign ions have been studied and the method has been applied for the determination of hydrazine in boiler feed water.     

Rapid Method for the Micro-Determination of Hydrazine by Amperometric Titration With Potassium Iodate

Abstract

An amperometric method, with potassium iodate as the titrant, for the rapid and precise determination of micro amounts of hydrazine salts is described. Hydrazine dihydrochloride, hydrazine sulfate and hydrazine hydrate could be quantitatively analyzed at the concentration range of 4 × 10^?7 -4×10^?3 M in the presence of 5 M hydrochloric acid. Hydrazine salts, 2×10^?4 -4×10^?3 M, were titrated in 5 minutes with a relative error and a relative standard deviation of 0.1%. It was also found that hydrazine dihydrochloride can be precisely determined, without any interference, even in the presence of hydroxylamine which is ten times as much as the former.

The suitable applied potential between the rotating platinum indicator microelectrode and the silver plate-silver chloride reference electrode was + 0.7V.     

A novel turn-on fluorescent probe for Hg2+ detection based on rhodamine B spirolactam derivative

ABSTRACT

In this work, a new turn-on fluorescent probe 1 for Hg²⁺ ions detection based on rhodamine B spirolactam was reported. Among tested metal ions, probe 1 shows high selectivity towards Hg²⁺ in the the mixture solution of methanol and 0.02 M HEPES buffer (V/V = 9:1, pH = 7.2). No absorption and emission band of probe 1 was observed in the range from 450 to 700 nm. While only addition of Hg²⁺ to probe 1 could lead to appearance of a new absorption band centered at 553 nm and a fluorescence emission band around 577 nm upon excitation at 520 nm. Moreover, it exhibits excellent linear relationship (R² = 0.9993) between fluorescence intensity at 577 nm and the concentration of Hg²⁺ from 1.6 to 32 μM. The sensing mechanism was proven to be spirolactam ring open induced by Hg²⁺ through ¹H NMR, MS, absorption and fluorescence spectra. In addition, probe 1 could detect Hg²⁺ in real water samples and on filter paper, which demonstrates its application in environment science.     

Simple Synthesis of Red Iridium(III) Complexes with Sulfur-Contained Four-Membered Ancillary Ligands for OLEDs

Phosphorescent iridium(III) complexes have been widely researched for the fabrication of efficient organic light-emitting diodes (OLEDs). In this work, three red Ir(III) complexes named Ir-1, Ir-2, and Ir-3, with Ir-S-C-S four-membered framework rings, were synthesized efficiently at room temperature within 5 min using sulfur-containing ancillary ligands with electron-donating groups of 9,10-dihydro-9,9-dimethylacridine, phenoxazine, and phenothiazine, respectively. Due to the same main ligand of 4-(4-(trifluoromethyl)phenyl)quinazoline, all Ir(III) complexes showed similar photoluminescence emissions at 622, 619, and 622 nm with phosphorescence quantum yields of 35.4%, 50.4%, and 52.8%, respectively. OLEDs employing these complexes as emitters with the structure of ITO (indium tin oxide)/HAT-CN (dipyra-zino[2,3-f,2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile, 5 nm)/TAPC (4,4′-cyclohexylidenebis[N,N-bis-(4-methylphenyl)aniline], 40 nm)/TCTA (4,4″,4″-tris(carbazol-9-yl)triphenylamine, 10 nm)/Ir(III) complex (10 wt%): 2,6DCzPPy (2,6-bis-(3-(carbazol-9-yl)phenyl)pyridine, 10 nm)/TmPyPB (1,3,5-tri(mpyrid-3-yl-phenyl)benzene, 50 nm)/LiF (1 nm)/Al (100 nm) achieved good performance. In particular, the device based on complex Ir-3 with the phenothiazine unit showed the best performance with a maximum brightness of 22,480 cd m⁻², a maximum current efficiency of 23.71 cd A⁻¹, and a maximum external quantum efficiency of 18.1%. The research results suggest the Ir(III) complexes with a four-membered ring Ir-S-C-S backbone provide ideas for the rapid preparation of Ir(III) complexes for OLEDs.     

Determination of phenothiazines by charge-transfer complex formation with chloranilic acid

A rapid and sensitive spectrophotometrc method has been developed for the microdetermination of some phenothiazine derivatives as the pure substances and in different dosage forms. The method depends on the formation of stable donor-acceptor complexes between phenothiazines and chloranilic acid in an acetonitrile-2-propanol solvent mixture. The resulting intensely purple chloranilic acid radical anion possesses a characteristic absorption maximum at 515 nm. Beer's law is obeyed over the concentration ranges 1-6, 1-10 and 5-30 mug ml for prochlorperazine dimaleate, trifluoperazine dihydrochloride and thiethylperazine dihydrochloride, with apparent molar absorptivities of 7.76 x 10(4), 1.95 x 10(4) and 6.64 x 10(3) 1. mole(-1).cm(-1), respectively. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.     

Spectrophotometric Determination of Steroid Oximes

Abstract

A spectrophotometric procedure for the determination of steroid oximes is described utilizing 11β-hydroxy-iia-methyl-5β-pregnane -3, 20 -dione dioxime (I) and iia-hydroxy-progesterone dioxime (II) as models. The method is based on (a) acid hydrolysis to release hydroxylamine, (b) oxidation of hydroxylamine to nitrous acid with iodine, (c) diazotization of sulfanilic acid with the nitrous acid, (d) coupling of the diazonium compound with N-(i-naphthyl)-ethylenediamine dihydrochloride, and (e) measurement of the azo dye at 550 nm. A stoichiometric yield of hydroxylamine is obtained. Analyses of I and II have given typical recoveries (mean ± S. D.) of 99.5 ± 1.1% and 97.8 + 3.5%, respectively. The method is sensitive to ≥ 0.3 × 10^?5 M dioxime.     

Copolyfluorenes containing phenothiazine or thiophene derivatives: Synthesis,characterization, and application in white‐light‐emitting diodes

Four copolyfluorenes chemically doped with 0.1 and 1 mol % 3,7‐bis[2‐thiophene‐2‐yl)‐2‐cyanovinyl]phenothiazine ( PFPhT ) or 2,5‐bis[2‐(thiophene‐2‐yl)‐2‐cyanovinyl]thiophene chromophores ( PFThT ) were synthesized using the Suzuki coupling reaction and applied in white‐light‐emitting devices. They were characterized by GPC, elemental analysis, DSC, TGA, optical spectra, and cyclic voltammetry. They exhibited good thermal stability (T_d > 420 °C) and moderate glass transition temperatures (>95 °C). The PhT‐Br and ThT‐Br showed PL peaks at 586 and 522 nm (with a shoulder at 550 nm). In film state, PL spectra of the copolymers comprised emissions from the fluorene segments and the chromophores due to incomplete energy transfer. Both monomers exhibited low LUMO levels around ?3.50 to ?3.59 eV, whereas the PhT‐Br owned the higher HOMO level (?5.16 eV) due to its electron‐donating phenothiazine core. Light‐emitting diodes with a structure of ITO/PEDOT:PSS/copolymer/Ca(50 nm)/Al(100 nm) showed broad emission depending on the chromophore contents. The maximum brightness and maximum current efficiency of PFPhT2 ( PFThT1 ) device were 8690 cd/m² and 1.43 cd/A (7060 cd/m² and 0.98 cd/A), respectively. White‐light emission was realized by further blending PFPhT2 with poly(9,9‐dihexylfluorene) (w/w = 10/1), with the maximum brightness and maximum current efficiency being 10,600 cd/m² and 1.85 cd/A. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 833–844, 2009     

Supramolecular assemblies of Al3+ complexes with vitamin D3 (cholecalciferol) and phenothiazine. Encapsulation and complexation studies in β-cyclodextrin

Ternary assemblies of β-cyclodextrin with cholecalciferol (or vitamin D₃) or phenothiazine and Al³⁺ ions were studied. The stability constants of aluminium binary complexes with cholecalciferol or phenothiazine and of ternary assemblies (β-cyclodextrin, cholecalciferol or phenothiazine and Al³⁺) were determined using potentiometric titrations at 25 °C (I = 0.100 M). The ¹³C NMR spectra of the supramolecular structures in the solid state showed that ternary supramolecular structures associating β-cyclodextrin, cholecalciferol or phenothiazine and aluminium(III) ions were obtained. Finally, X-ray powder diffraction patterns showed that the ternary assemblies with phenothiazine are channel type inclusion complexes.     

Colorimetric Determination of Some N-Substituted Phenothiazine Derivatives Using 2-Iodoxybenzoate

Abstract

A new, sensitive colorimetric method has been described for the quantitative determination of six N-substituted phenothiazines. the method depends on the formation of stable phenothiazine free radical by the use of 2-iodoxybenzoate as chromogenic reagent. the drug in 50% sulphuric acid is treated with reagent (5×10^?4 M). the produced red or purple color possesses characteristic absorption maximum for each of the drugs tested. Beer's law is obeyed over the concentration range 2-30 μg.ml^?1 with apparent molar absorptivities ranging from 9.4-12.4×10^?3 for the studied phenothiazine derivatives. the average % recovery is 99.5±0.96 - 101.6±1.01. the method was applied successfully to the microdetermination of promazine. HCl, chlorpromazine, HCl, promethazine. HCl, perphenazine, levomepromazine HCl and mesoridazine besylate either in pure form or incorporated in their representative pharmaceutical preparations. the stoichiometry of the reaction was assumed and a reaction mechanism was suggested. the precision of the assay was comparable with the official ones.     

Calibration of Circular Dichrometers

Abstract

The tris (hydroxymethyl)aminomethane salt of d-10-camphorsulfonic acid (TRIS-CSA) provides a convenient, non-hygroscopic alternative to the parent compound in the calibration of circular dichrometers. The molecular ellipticities, [6], of TRIS-CSA at 291 and 191 nm are 8015± 11 and -16, 130± 40 deg cm² dmol^?1, respectively. The circular dichroism (CD) maxima in terms of δε are 2.429 1 cm^?1 mol^?1 at 291 nm and -4.888 1 cm^?1 mol^?1at 191 nm. TRIS-CSA has an ORD peak at 306.5 nm, a zero crossover at 292 nm, and a trough at 270.5 nm (molecular rotation, [M]_306.5=4475± 10, [M]_270.5= -5615± 10 deg cm² dmol^?1), and a molar absorptivity, ε, of 35.9± 0.2 1 cm^?1 mol^?1 at 286 nm.