Spegtrophotometrig Determination of α -Tocopherol Acetate in Soft Capsules

Abstract

Two spectrophotometric methods have been described for the determination of α -tocopherol acetate (vitamin E) in soft capsules. The first method applies the orthogonal function method under least squares. The quadratic coefficients calculated over the wavelength range 277 - 304 nm at 4-nm intervals in chloroform were reproducible and independent of ethyl oleate concentration. The second method applies the second derivative (D₂) to correct for irrelevant absorbance due to ethyl oleate The peak trough amplitude at 271 - 287 nm was in linear correlation to the concentration of vitamin E. The recoveries obtained using the proposed methods agreed with those obtained using the official proceduce.     

A comparative study of Mentha arvensis L. and Mentha haplocalyx Briq. by HPLC

We have developed a new method to simultaneously determine five marker compounds in Menthae Herba via HPLC/PDA – including hesperidin (1), rosmarinic acid (2), diosmin (3), didymin (4) and buddleoside (5). The newly developed method was successfully used to analyse for two species (Mentha arvensis L. and Mentha haplocalyx Briq.) of Menthae Herba, and the satisfactory results were obtained from the validation of developed method. The pattern analysis could greatly discriminate between M. arvensis L. and M. haplocalyx Briq. In conclusion, the proposed HPLC/PDA method is suitable for quality evaluation of Menthae Herba.     

In vitro anti-acne activity of phytoactives from the stem bark of Artocarpus hirsutus Lam. and characterisation of pyranocycloartobiloxanthone A as a mixture of two anomers

This study is aimed to isolate the phytoactives from the stem bark of Artocarpus hirsutus and evaluate their in vitro anti-acne activity. The ethanolic stem bark extract of A. hirsutus provided two major phytoactive constituents: (i) pyranocycloartobiloxanthone A, (1) and (ii) Artonine E, (2) whose structures were determined by NMR and MS spectroscopic analysis. The present study is the first to report compound 1 as a mixture of two anomers (α and β), approximately 70:30 ratio. Both compounds 1 and 2 were isolated for the first time from this plant. In vitro anti-acne activity of compounds 1 and 2 were evaluated by agar well diffusion method and the minimum inhibition was determined by broth micro dilution method. The result of anti-microbial activity (MIC = 2.0 μg/mL each) is comparable to antibiotic, Clindamycin (MIC = 0.03 μg/mL) and clearly demonstrate their potential as anti-acne agents.     

Effective Separation of Bacterial Phospholipids and Neutral Lipids in one Dimensional Thin Layer Chromatography

Abstract

A method for effective separation of phospholipids and neutral lipids of E. Coli in one dimensional thin layer chromatography on ready-made plates has been proposed. The chromatographing was made successively in three different solvent systems. About ten lipid components were shown to be separated on the same plate.     

Determination of Creatinine in Plasma by the Apparent Content Curves Method

Summary

A mathematical method that avoids spectral interferences in creatinine determination in plasma by the Jaffé reaction is proposed. The experimental conditions are studied and the accuracy and precision of the method are tested against two reference methods. The proposed method provides good results and it is suitable for creatinine determination in plasma.     

K Ratio H-Point Standard Additions Method

Abstract

A modification of H-point standard additions method is proposed in order to obtain an unbiased analyte concentration when both analyte and interferent are present in a sample. The method is called “K ratio H-point standard additions method.” The method uses the analytical signal data at two selected wavelengths and the K ratio of an interferent determined by using the method proposed by Ni Yongnian et al. at the same wavelengths, giving two straight lines that have a common point H with coordinates (-C_H, A_H), where C_H is the unknown analyte concentration and A_H is the absorbance of an interferent at one of the two selected wavelengths, which depends on the calculating method of K ratio. Examples of application of the proposed method are given.     

Indirect Determination of the Pesticide Malathion by Atomic Absorption Spectrophotometry

Abstract

A method for the indirect determination of the pesticide malathion by atomic absorption spectrophotometry (AAS) is proposed and compared with the standard spectrophotometric method.

A study of the influence of the different variables on the hydrolysis and extraction is carried out in order to obtain the best experimental conditions.

The proposed method offers clear advantages over the standard procedure because of the instability of the Cu (II) complex formed. Both methods are applied to the determination of malathion in two commercial formulations.     

Bis-Thiourea Bearing Aryl and Amino Acids Side Chains and Their Antibacterial Activities

Abstract

A series of symmetrical 1,3-bis thiourea 1a–e and 1,4-bis thiourea derivatives 2a–e have been successfully synthesized from the reactions of amines with 3-acetylbenzoyl isothiocyanate and 4-acetylbenzoyl isothiocyanate, respectively. All the synthesized compounds were characterized by FT-IR spectroscopy and ¹H and ¹³C NMR spectroscopy. The compounds were screened for their antibacterial activity by turbidimetric method using gram-negative bacteria (E. coli ATCC 8739) using turbidimetric method. The newly synthesized bis-thiourea derivatives bearing aryl side chains showed good antibacterial activity against E. coli. The effect of the molecular structure of the synthesized compounds on the antibacterial activity is discussed.     

Stability Indicating Hplc Method for the Determination of Sparfloxacin (Spar)

ABSTRACT

A rapid, sensitive and stability indicating method for the determination of sparfloxacin (SPAR) by RP - HPLC has been developed on a Merck RP - Select B (5 μm; 12.5 cm x 4.0 mm) column using a mobile phase of water: acetonitrile: triethylamine (80 : 20 : 0.2 v/v) pH of which was adjusted to 2.6 with orthrophosphoric acid. The flow rate was 1 ml / min. and the detection was carried out at 304 nm using Waters 486 variable wavelength detector. The retention time for SPAR was 7.2 min. Linearity range was from 8 - 1000 ppm. The method showed good precision and accuracy when applied to two brands of tablets containing SPAR. In alkaline media SPAR is stable where as it undergoes degradation in acidic and oxidising conditions generating different degradation products the nature of which is required to be established. The proposed method nicely separates the degraded products from SPAR and hence can be used as stability indicating method for the assay of SPAR.     

CdS Quantum Dots as Fluorescence Probes for the Detection of Selenite

Abstract

Water-soluble cadmium sulfide (CdS) quantum dots (QD) capped by mercaptoacetic acid were synthesized by aqueous-phase arrested precipitation and characterized by transmission electron microscopy, a spectrofluorometer, and an ultraviolet visible (UV-Vis) spectrophotometer. Based on the fluorescence quenching of CdS QD by selenite in the presence of glutathione (GSH), a simple, rapid, sensitive, and selective detection method for selenite was proposed. Under the optimum conditions, the calibration graph was linear in the range of 0.05 µmol L^?1 to 11.2 µmol L^?1. The limit of detection is 0.03 µmol L^?1. The usefulness of the proposed method was evaluated for the determination of selenite in sodium selenite tablet and sodium selenite and vitamin E injection, and the results agreed with the labeled values. In addition, the effect of foreign ions (common anions and biologically relevant cations) on the fluorescence of the CdS QD was examined to evaluate the selectivity. The quenching mechanism is also described.     

Simultaneous Determination of Methadone,Heroin and Their Metabolites in Hair By Gc-Ms

ABSTRACT

A method for the simultaneous identification and quantitation of methadone, codeine, morphine, monoacetylmorphine and heroin in hair by use of gas chromatography in combination with mass spectrometry (GC-MS) is proposed. Hair samples are incubated with dithiothreitol and subsequently subjected to enzymatic hydrolysis with Pronase E. Following addition of their deuterated internal standards, samples are subjected to liquid-liquid extraction in ToxiTubes A ⁸. The residue thus obtained is derivatized with N, O-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (BSTFA/TMCS) and directly injected into a GC-MS in the single ion mode (SIM). The calibration curve is linear over the range 0.5-50 ng/mg for all the analytes. The method was reproducible with limits of detection between 0.06 ng/mg (methadone) and 0.29 ng/mg (codeine). This method was applied in a 5-years-old child suspected to be victim of a coercive drug administration.     

Simultaneous Spectrophotometric Determination of Levodopa and Benserazide in a Pharmaceutical

ABSTRACT

A method based on a partial least-squares calibration (PLS) for the simultaneous spectrophotometric determination of levodopa (I) and benserazide (II) in a commercially available pharmaceutical preparation is proposed. The calibration procedure was developped by using laboratory made mixtures of I and II, and optimized by selecting the most suitable wavelength range and spectral mode. The relative standard error of prediction (RSEP %) was 0.5% and 0.9% with a limiting reproducibility (R) of 4 10^?6 M and 1.5 10^?6 M for levodopa and benserazide, respectively The proposed method is straightforward, expeditious and precise. Its results are consistent with those provided by HPLC for the two analytes.     

Isolation and structure determination of a new flavone glycoside from seed residues of seabuckthorn (Hippophae rhamnoides L.)

In this study, a valid method was established for the isolation and purification of flavone glycosides from Hippophae rhamnoides L. seed residues using high-speed counter-current chromatography in one step, with a solvent system of ethyl acetate-methanol-n-butyl alcohol-water (9:1:0.5:9, v/v/v/v). A total of 28.8 mg compound I and 57.3 mg compound II were obtained from 200 mg of flavone H-glycosides rich extract, with purities of 98.3 and 96.4%, respectively. The structures of two compounds were identified by MS and NMR. 3-O-β-D-Sophorosylkaempferol-7-O-{3-O-[2(E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoyl]}-α-L-rhamnoside is compound I and compound II named hippophanone is a new compound were identified by MS and NMR. The method was efficient and convenient, which could be used for the preparative separation of flavone glycosides from H. rhamnoides L. seed residues.     

N-(R-Cyclopropyl) Trifluoroacetimidoyl Phosphonates

Abstract

A convenient synthetic approach for previously unknown N-(R-cyclopropyl)trifluoroacetimidoyl phosphonates 5a,b (R?H, CF₃) was developed on the basis of the reaction of respective trifluoroacetimidoyl chlorides with triethyl phosphite. It was shown that imidoyl phosphonates 5a,b exist as equilibrium mixture of Z/E isomers (Z:E ～92:8). Activation parameters of Z–E isomerization were evaluated by ¹⁹F NMR spectroscopy. Catalytic hydrogenation of 5a,b can serve as a convenient method for the synthesis of trifluoroethylaminophosphonates with a rigid N-cyclopropyl group.     

Analytical Study of Methorexate

Abstract

Spectrophotometric, coloriaetric and differential pulse polarographic “DPP” techniques were adopted for microdetermination of methotrexate in pure form and in pharmaceutical preparations. The spectrophotometric method was based on measuring the light absorbance at 303 nm in 0.1 N NaCH. The colorimetric method was based on coupling the diazotised methotrexate with 8-hydroxy quinoline in alkaline medium and measuring the colour developed at 430 nm. The three proposed techniques were compared with the E.P. 1980. method. The DPP method was further used for methotrexste determination in presence of some biological fluids.     

Microdetermination Par Polarographie Impulsionnelle Differentielle Du Chrome (VI) Present Dans Les Ciments Industriels

Abstract

The toxicological literature often mentions that chromium(VI), present and added to cements for technical reasons, induce dermatosis. Good analytical techniques are not available. The D.P.P. method proposed here for the microdetermination of chromium (VI) in cements is fast and selective. The cation is solubilized by stirring the cement with distilled water. After filtration, the solution is submitted to differential pulse polarography. Generally, samples analysed contain between 1 and 12 mg of chromium (VI) per kg of cement. The potential peak is -0.19 V v.s. S.C.E. for the pure chromium (VI) solution and is shifted toward between -0.25 and -0.30 V v.s. S.C.E. when chromium (VI) is extracted from real cement samples The detection limit is 0.3 ppm.     

(±) Benzomalvins E isolated from Penicillium sp. SYPF 8411 in the rhizosphere soil of Codonopsis clematidea

Abstract

(+) Benzomalvins E (1) and (-) Benzomalvins E (2), a pair of epimeric derivatives, together with three known benzomalvins (3–5), were isolated from solid cultures of a interrhizospheric fungus Penicillium sp. SYPF 8411. The planar structure of (+) Benzomalvins E (1) has been previously reported. While, the absolute configuration of compound 1 was established by X-ray crystallographic analysis for the first time. The planar structure of the new compound 2 were elucidated by detailed interpretation of their HR ESI-TOF MS and NMR spectroscopic data. The absolute configuration of compound 2 was established by Rh₂(OCOCF₃)₄-induced CD spectral data and the electronic circular dichroic (ECD) method. Furthermore, the epimerization induced by pH, temperature and H₂O was revealed. Benzomalvins (1–3, 5), a type of indoximod, enhanced the cytotoxic capability of 5-fluorouracil against A549.     

An Enzyme Immunoassay of Catalytically Active Proteases

Abstract

A method is proposed to assay catalytically active protease. The method is based on the subsequent inter action of the enzyme with a protein inhibitor immobi lized on polysterene and with antibodies labelled with a high-activity enzyme. Optimal conditions have been chosen for assaying alkaline protease from Bacillus subtilis (subtilisin) by ELISA with peroxidase as label, employing two protein serine protease inhibitors isolated from duck egg white and maize seeds. The proposed method enables the detection of the catalyti cally active enzyme at concentrations as low as 1 ng/ml for 1.5 hr. The c. v. of the assay is less than 5%. The method can be used to determine the equilibrium con stant of the enzyme-inhibitor reaction in solution.     

Non-Aqueous Titrimetric Determination of Sulphadimidine Sodium and Sulphadiazine Sodium in Injections

Abstract

The behaviour of sodium salts of two heterocyclic sulphonamide derivatives (Sulphadimidine and sulphadiazine) in non-aqueous titrimetry was studied. Accordingly a simple and accurate procedure for their determination, based on their titration in acetic anhydride-acetic acid solvent system (5:1) with acetous perchloric acid solution is proposed. Results obtained agreed with those of a pharmacopoeial method.     

Simple preparative synthesis of spinochrome e,a pigment from sea urchins of the genus <Emphasis Type="Italic">Echinothrix</Emphasis>

A preparative synthesis of spinochrome E (2,3,5,6,7,8-hexahydroxy-1,4-naphthoquinone, 1), a metabolite of sea urchins of the genus Echinothrix, is proposed starting from 2,3-dichloro-6,7-diethoxynaphthazarine (4) with simultaneous substitution of the Cl atoms by hydroxyl- and nitro-groups, reduction of the latter, and subsequent removal of alkoxy groups and hydrolysis of the amine in the resulting 3-amino-2-hydroxy-6,7-diethoxynaphthazarine (6).