Sensitive and rapid spectrophotometric methods for determination of anticancer drugs.

Sensitive, rapid, and simple spectrophotometric methods were developed for determination of the anticancer drugs vinblastine sulfate (VBS) and vincristine sulfate (VCS), which belong to the class of vinca alkaloids. The first method is based on the reaction of VBS and VCS with diazotized dapsone, forming yellow azo products with absorption maxima at 430 nm. The colored species obey Beer's law in the concentration range of 0.5-24 microg/mL for VBS and 0.5-12 microg/mL for VCS. The second method describes the reaction of VBS and VCS with iron(III) and subsequent reaction with ferricyanide in hydrochloric acid medium to yield blue products with absorption maxima at 750 nm. The Beer's law range for this method is 0.1-4 microg/mL for VBS and 0.5-10 microg/mL for VCS. With both methods, colored species were stable for 1 h. The methods are simple and reproducible and are applied for determination of VBS and VCS in pharmaceutical formulations. Commonly encountered pharmaceuticals added as excipients do not interfere in the analysis and the results obtained in the analysis of dosage forms agree well with the labeled contents

Kinetics and mechanism of oxidation of L-isoleucine and L-ornithine hydrochloride by sodium N-bromobenzenesulphonamide in perchloric acid medium

Kinetic studies of the oxidation of L-isoleucine (ISL) and L-ornithine hydrochloride (ORH) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) were studied in aqueous perchloric acid medium. The rate shows first-order dependence on both [BAB](0) and [amino acid](0) and inverse first-order dependence on [H+] for ISL and first-order dependence on [H+] for ORE. The rate of reaction decreased with decreases in the dielectric constant of the medium. The addition of benzenesulphonamide (BSA), which is one of the reaction products, had no significant effect on the reaction rate. The rate remained unchanged with the variation in the ionic strength of the medium for ISL, whereas the rate decreased with increases in the ionic strength of the medium for ORR Isovaleronitrile and 3-(methylamino)propionitrile were identified as the products. Thermodynamic parameters were computed by studying the reactions at different temperatures (298-316 K). The rate laws derived are in excellent agreement with the experimental results. Plausible mechanisms are suggested

3-Aminophenol as a novel coupling agent for the spectrophotometric determination of sulfonamide derivatives

A rapid, simple and sensitive spectrophotometric method for the determination of some sulfa drugs is described. The method is based on the formation of orange yellow colored azo product by the diazotization of sulfonamides, viz., dapsone (DAP), sulfathiazole (SFT), sulfadiazine (SFD), sulfacetamide (SFA), sulfamethoxazole (SFMx), sulfamerazine (SFMr), sulfaguanidine (SFG) and sulfadimidine (SFDd) followed by a coupling reaction with 3-aminophenol in aqueous medium. Absorbance of the resulting orange yellow product is measured at 460 nm and is stable for 6 days at 27°C. Beer's law is obeyed in the concentration range of 0.05–8.0 μg/ml at the wavelength of maximum absorption. The method is successfully employed for the determination of sulfonamides in various pharmaceutical preparations and common excipients used as additives in pharmaceuticals do not interfere in the proposed method. Plausible reaction mechanism is proposed for the formation of the azo product

Crystal structure of 2-chloro-3-(beta-nitrovinyl)quinoline

2-Chloro-3-(beta-nitrovinyl)quinoline (CNQ) was crystallographically studied owing to its medicinal properties and its occurrance in numerous commercial products, including pharmaceuticals, fragrances and dyes. The vinyl group is planar, and takes up an extended conformation. An hydrogen bonding of C-H...N type helps to stabilize the molecules in the unit cell

Crystal structure of 4-Amino-3-(4′-chlorophenyl)-4-H-[1,2,4]-triazolo-5-thiol

The crystal structure of 4-amino-3-(4′-chlorophenyl)-4H-[1,2,4]-triazolo-5-thiol (ACPTT) was determined by crystallographic methods. There are two crystallographically independent molecules in the asymmetric unit and are related by pseudo inversion symmetry with each other. A number of C-H…N and N-H…N types of intermolecular interactions stabilize the molecules in the unit cell in addition to van der Waals forces

Crystal structure of a tetrazole derivative

Abstract 5-(4'-Methyl-1,1'-biphenyl-2-yl)-1H-tetrazole(MBT), C28H24N8, CCDC: 223082, F.W.=472.55, triclinic, P1, a=4.99(1)Å, b=14.25(4)Å, c=16.63(5)Å, α = 90.27(5)°, β = 91.19(5)°, γ = 90.64(5)°, V = 1182(6)Å3, Z = 4, Dcal = 1.327 Mgm-3, μ = 0.084mm-1, F000 = 496, λ (MoKα) = 0.71073Å, final R1 and wR2 are 0.0924 and 0.2309, respectively. There are two crystallographically independent molecules in the asymmetric unit. The dihedral angles between the two phenyl rings of the biphenyl ring system are 44.2(2)° and 44.3(2)° for the two molecules respectively. The molecules are stabilized by N-H…N and C-H…N types of intermolecular hydrogen bonds in the unit cell in addition to van der Waals forces. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Crystal structure of bis(2-butyl-4-chloro-imidazole)5-iminoethane

The title compound (C18H26N6Cl2) crystallizes in monoclinic space group P21/c with a = 14.867(4) Å}, b = 7.758(2) Å}, c = 9.671(3) Å}, β = 108.78(1)∘, V = 1056.0(5) Å}3, Z = 2, D cal = 1.250 Mg/m3 at T = 293 K. The structure was solved by direct methods and refined by full-matrix least-squares procedures to final R = 0.0650 and wR = 0.1719 using 2493 reflections. The imidazole ring is planar and the n-butyl chain adopts an extended conformation. The molecules in the crystal are stabilized by N–H ⋅s N type of intermolecular hydrogen bondings in addition to van der Waals forces

Crystal Structures of two Imidazole Derivatives

2-n-Butyl-5-chloro-3H-imidazole-4-carbaldehyde (BCIC), C8H11ClN2O. F.W. = 186.64, monoclinic, P2(1)/c, a = 7.2617(3) Angstrom, b = 13.2067(6) Angstrom, c = 9.8491(4) Angstrom beta = 101.76(1)degrees, V = 924.74(7) Angstrom(3), Z = 4, D-cal = 1.341 Mgm(-3), mu = 0.367 mm(-1), F-000 = 392, lambda (MoKalpha) = 0.71073 Angstrom, final R1 and wR2 are 0.049 and 0.126, respectively. 2-n-Butyl-4-chloro-1 [(2'-cyanobiphenyl-4-yl)methyl]-5-hydroxymethyl imidazole (BCCI), C22H22ClN3O, F.W. = 379.88, triclinic, P (1) over bar, a = 8.198(2) Angstrom, b = 10.997(3) Angstrom, c = 11.524(2) Angstrom, alpha = 90.83(2)degrees, beta = 94.31(2)degrees, gamma = 109.45(2)degrees, V = 976.0(2) Angstrom(3) , Z = 2, D-cal = 1.293 Mgm(-3), mu = 1.856 mm(-1), F-000 = 400, lambda (CuKalpha) = 1.5418 Angstrom, final R1 and wR2 are 0.081 and 0.239, respectively. The imidazole ring in both the molecules is planar. The n-butyl group adopts a bent conformation in BCIC where it is in extended conformation in BCCI. The biphenyl ring system orients at an angle of 45.1(1)degrees in BCCI. The molecules are stabilized by N-H...N and O-H...N type hydrogen bonds in addition to van der Waals forces

Crystal structures of two triazole derivatives

3-Phenyl-4-amino-5-mercapto-1,2,4-triazole(PAMT), C8H8N4S, F.W. = 192.24, triclinic, P (1) over bar, a = 6.1698(3)Angstrom, b = 7.1765(1)Angstrom, c = 9.9894(3)Angstrom, alpha = 81.87(1)degrees, beta = 84.97(2)degrees, gamma = 78.81(2)degrees, V = 428.72(3)Angstrom(3), Z = 2, D-cal = 1.489 Mgm(-3) , mu = 0.330 mm(-1), F-000 = 200, lambda(MoKalpha) = 0.71073 Angstrom, final R1 and wR2 are 0.0871 and 0.2170, respectively. 3-(4-Methylphenyl)-4-amino-5-mercapto-1,2,4-triazole (MAMT), C9H10N4S, F.W. = 206.27, triclinic, P (1) over bar, a = 5.996(1)Angstrom, b = 7.582(2)Angstrom, c = 11.143(1)Angstrom, alpha = 73.16(1)degrees, beta = 89.65(2)degrees, gamma = 87.88(1)degrees, V = 484.52(3)Angstrom(3) , Z = 2, D-cal = 1.414 Mgm(-3) , mu = 2.674 mm(-1), F-000 = 216, lambda (CuKalpha) = 1.5418 Angstrom, final R1 and wR2 are 0.0656 and 0.1820, respectively. In both of the molecules the triazole rings are planar and oriented at angles of 5.7(1)degrees and 1.4(2)degrees with the respective phenyl rings in MAMT and PAMT. The molecules in the unit cell are stabilized by N-H...N type hydrogen bonds in addition to van der Waals forces