New Rapid Assay for Nafcillin by Spectrofluorimetry in Pharmaceutical Dosage

Abstract

A method for the spectrofluorimetric determination of nafcillin is proposed (λ_ex = 226 nm, λ_em = 366 nm), for concentrations between 0.10 and 1.0 μg mL^?1. The method was performed in ethanol/water medium (30% V/V), at apparent pH 6.0 provided by adding of phosphate buffer solution with pH = 6.20.

The obtained values of detection and determination limits are 0.016 and 0.054 μg mL^?1, respectively.

The method was successfully applied to assay a commercial injection containing nafcillin sodium monohydrate.     

Rapid Determination of Lactulose in Milk Using Seliwanoff's Reaction

ABSTRACT

A rapid method based on Seliwanoff's reaction to distinguish between UHT and sterilised milk was proposed. Lactulose was determined directly in milk with no treatment. Analysis of raw milk and its carbohydrates showed that the only interference was the relatively high concentration of lactose, which imposes the lower limit of detection. Small variations of lactulose (9mg dL^?) during heat treatment could be observed when the absorbance was measured against pretreated milk (blank). This method showed a linear range between 17–170mg dL^? and a detection limit lower than that of the official HPLC method. This novel procedure was compared with a commercially available enzymatic method and the results obtained correlated well.     

A Rapid Spectrophotometric Method to Resolve Ternary Mixtures of Propyphenazone, Caffeine, and Acetaminophen in Tablets

Summary.  A simple and rapid derivative spectrophotometric assay procedure is described for the analysis of caffeine (1), acetaminophen (2), and propyphenazone (3) in tablet formulations. The concentration range of application is 5.0–25.0 μg·cm⁻³ for 2 and 3 and 1.0–5.0 μg·cm⁻³ for 1. The method involves the extraction of the drugs from tablets with 0.1 N H₂SO₄, filtration, appropriate dilution, and measurement of the fourth derivative absorbance values at zero crossing wavelengths of 230.0, 263.2, and 256.6 nm for 1, 2, and 3. As a reference method, a reversed phase HPLC procedure was developed. Commercially available tablets were analyzed; statistical comparison of the results with those obtained from the reference method showed good agreement. The derivative spectrophotometric method has the advantage of being simple, rapid, inexpensive, and easy to perform. Received April 18, 2001. Accepted (revised) June 5, 2001     

Rapid High Performance Liquid Chromatographic Determination of Ampicillin in Human Urine

Abstract

A rapid, sensitive and specific HPLC assay for the determination of ampicillin in human urine is developed.

Ampicillin was directly measured in human urine at 225 nm using a reversed phase column (Synchropack RP-P) and a mobile phase composed of (1:9 methanol-sodium acetate solution, 0.01 M, pH 4). The analysis required no longer than 10 min. Linear correlation between the peak height ratio of ampicillin to cefoxitin sodium (internal standard) and ampicillin concentration in urine over the range 10–100 μg ml^?1 was obtained. The developed method proved to be advantageous as it monitors ampicillin level in urine. Moreover, the urinary excretion of ampicillin in human subjects after an oral administration of 500 mg ampicillin capsules was established using the proposed method.     

SYNTHESES AND SOME PROPERTIES OF SULFOXIDES,SULFILIMINES, AMINOSULFONIUM SALTS AND SULFOXIMINES CONTAINING PYRIDINE NUCLEI

Abstract

Several 2-pyridyl sulfides (1) (e.g., methyl (1a), ethyl (1b), isopropyl (1c), benzyl (1d), 1-phenylethyl (1e), l-menthyl (If) 2-pyridyl sulfides; and bis(2-pyridylthio)methane (1g), and methyl 2-(N-oxy-pyridyl) sulfide (1h) were prepared by the usual method. Sulfoxides (2) were prepared by oxidation of the corresponding sulfides with m-chloroperbenzoic acid in good yields. A few sulfoxides were found to work as phase-transfer catalysts for some typical nucleophilic reactions in nonpolar solvents such as benzene, and in two-phase systems such as benzene-water. S-2-Pyridyl-N-(p-toluenesulfonyl) sulfilimines (3) were prepared upon treatment of sulfides with Chloramine-T. Hydrolysis of N-(p-toluenesulfonyl)-2-pyridyl-o-tolylsulfilimine (3i) with conc. sulfuric acid gave the corresponding free sulfilimine in a moderate yield. S-2-Pyridyl sulfoximines (4) were not obtained by the general method from the sulfoxides and hydrazoic acid. Alkyl-2-pyridyl sulfoximines, however, were obtained by oxidation of the free sulfilimines derived from the corresponding aminosulfonium salts (5) prepared by reaction of the sulfides with mesitylene-sulfonylhydroxylamine (MSH). These free sulfilimines and sulfoximines thus prepared were found to give adducts with a few copper salts.     

Preparation and Radical Oligomerization of anFe(II) Complex without Loss of Spin-Crossover Properties

Summary.  11-(4H-1,2,4-Triazol-4-yl)-undecylmethacrylate (1), a new ligand for Fe(II) spin-crossover (SCO) complexes containing a polymerizable group, was synthesized and characterized. The complex [Fe·1 ₃](BF₄)₂ (2) was obtained by reaction of 1 with Fe(BF₄)₂·6H₂O (molar ratio 1/Fe(II) = 3/1) in THF. Complex 2 showed a gradual spin-crossover between 80 and 230 K. The methacrylate units in the ligands of complex 2 could be oligomerized radically in solution (initiator: azoisobutyronitrile) without loss of the spin-crossover behaviour. Received May 30, 2000. Accepted December 10, 2000     

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.     

Regioselective Isomerisation of Highly Substituted 1-Methylenecyclohexenepoxides to the Corresponding Allylic Alcohols. Influence of the Base and of the Protecting Groups

Summary. Highly substituted 1-methylenecyclohexenepoxides 3, useful building blocks for a projected synthesis of wailupemycin A (1), were synthesized from (R)-carvone in eight synthetic steps in 23–40% overall yield. The regioselectivity of the subsequent isomerisation to the corresponding allylic alcohols was shown to depend on the basicity of the reagent and on the bulkiness of the protecting groups existing in 3. With diethylaluminum 2,2,6,6-tetramethylpiperidid (DATMP), secondary allylic alcohols 5 were formed exclusively. With strong bases such as a mixture of lithium di-iso-propylamide and potassium tert-butoxide (LIDAKOR), the tertiary allylic alcohol 6 was obtained as predominant product.To whom inquiries about the X-ray analysis should be addressed     

Spectrophotometric Determination of Neomycin With 2,4-Dinitrofluorobenzene

Abstract

A spectrophotometric method is described for the determination of neomycin based on the reaction with 2,4-dinitrofluorobenzene. the best conditions for the reaction were obtained by using 0.02 M borate buffer (pH 9.0) as diluent, under ambient conditions after 50 minutes of reaction.     

Comparison Between Four Radioimmunoassays for Plasma Estriol

Abstract

We have compared the results obtained for plasma estriol (E₃) when four radioimmunoassay methods were used to measure this steroid during various stages of human pregnancy. The first method used a nonspecific antiserum combined with a chromatographic step. The second method utilizes as binding reagent a specific antibody against estriol combined with the same chromatographic step. The last two methods involve solvent extraction only, combined with the specific antiserum. Dichloromethane and ether respectively are used as solvent. The lowest levels of E₃ were obtained with methods I and II. With dichloromethane extraction the E₃ levels were comparable to those obtained with methods I and II. When using ether extraction the E₃ levels were in most cases two to four times higher. Even with highly specific anti- E₃ sera, chromatography is still required to achieve specificity.     

A new indole-type alkaloid from the roots of Clematis florida var. plena

One new indole-type alkaloid, α-L-rhamnopyranosyl-(1→6)-β-D- glucopyranosyl 6-methoxy-3-indolecarbonate (1), together with three known alkaloids (2–4), one aromatic acid (5) and five known saponins (6–10), was isolated from the roots of Clematis florida var. plena. Their structures were established by NMR spectroscopic analysis and acid hydrolysis. In in vivo anti-inflammatory activity, n-butanol extract was found to be potent against ear edema in mice, with inhibition rate of 48.7% at a dose of 800?mg/kg. Furthermore, compounds 8 and 9 obtained from the n-butanol extract exhibited significant anti-inflammatory activities with inhibition rates of 50.9% and 54.7% at a dose of 200?mg/kg.     

Electrochemical Reduction of Metronidazole and Its Determination in Pharmaceutical Dosage Forms by D.C. Polarography

Abstract

A simple d.c. polarographic method has been developed for the determination of metronidazole in dosages forms. In Robinson - Britton buffer (pH 4.38) and in presence of 1.60 × 10^?3 % Triton X-100, the drug produced a well defined 4-electron polarographic wave followed by another wave of about half the height of the first wave. The current is proportional to the concentration and permits the drug to be determined by d.c. polarography in the concentration range 5.0 × 10^?5 -7.0 × 10^?4 M. Results obtained by the proposed method are in excellent agreement with that provided by the USP-XX method. A rapid, sensitive and accurate polarographic method for the determination of metronidazole in the tablets which are produced locally is proposed.     

Structural Effects of Oligosaccharide-Branched Cyclodextrins on the Dual Recognition toward Lectin and Drug

Bi-galactose-branched cyclodextrins (Bi-Gal-CDs)(1–6) having different spacer arm lengths between two terminal galactoses were foundto have the optimum length for association with PNA lectin. Also, the inclusioninteraction of the drug depended on the length of the spacer arms. The dual association of thesecompounds was quantitatively evaluated by SPR and compared to the other oligosaccharide-branchedCDs (Scheme 1). The number and the length of the spacer arm are important for theassociation both with the lectin and drug for the purpose of targeting drug-delivery systems.The association constants K of bi-Gal-CD (2) with rat liver cells showed a 60 timeshigher association than with PNA. Direct evidence of the association between PNA andbi-Gal-CD (2) was characterized by AFM observations. The results obtained strongly suggested a method to find a new design for the targeting drug carrier. In order toincrease the association with the cell, a sufficient spacer arm length is necessary for the effectivedual recognition of the oligosaccharide-CDs. In order to increase the inclusion of thedrug, the CD structure of a multi-saccharide branch is necessary.     

Application of the Coupled Redox and Complexation Reactions to Flow Injection Spectrophotometric Determination of Promazine

Abstract

A flow injection (FI) spectrophotometric method is proposed for the determination of promazine hydrochloride. The method is based on the coupled redox - complexation reactions which proceed in the promazine-iron(III) and 1,10-phenantroline system. A linear calibration graph was obtained between 2–12 ppm of promazine hydrochloride with a sampling rate of 163 samples h^?1. The proposed method was applied to the determination of promazine in pharmaceuticals.     

Extraction - Spectrophotometric Determination of Phosphate Using N-Phenylbenzohydroxamic Acid

Abstract

A simple solvent extraction and spectrophotometric method for the determination of micro amount of phosphate (PO₄) is described. Phosphate is selectively separated from associated elements by reacting it with calcium and extracting excess calcium with N-phenylbenzohydroxamic acid (PBHA) at pH 11.3. The excess calcium was determined in ultra-violet and visible region and hence the phosphate content was calculated. The Beer's law is obeyed in the range 0.5 ? 10.0 ppm at 340 nm and 0.25 - 8.0 ppm at 560 nm of phosphate for a fixed amount of calcium (20.0 ppm). These results are also compared with those obtained by atomic absorption spectrophotometry. The method has been applied for the determination of phosphate in pharmaceutical and other samples.     

Complexation of aminoglycoside antibiotics with metal cations as a derivatization reaction: Determination of gentamicin by equilibrium electrochemical and spectrophotometric methods

The complexation of aminoglycoside antibiotics with metal cations was proposed as a derivatization method for the further determination of the complex obtained by potentiometry with ion-selective electrodes (ISE), voltammetry at the interface between two immiscible electrolyte solutions (ITIES), and spectrophotometry. It was shown by the spectrophotometric method that gentamicin formed a 1: 1 complex with copper(II). For the potentiometric determination of gentamicin, we obtained ionophores that were ion associates formed by the gentamicin complex of copper(II) and tetraphenylborate derivatives as counterions. The transfer of the gentamicin complex of copper(II) was studied voltammetrically at the ITIES. The results obtained indicate that l antibiotic gentamicin can be directly determined as a complex with copper(II) by potentiometric, voltammetric, and spectrophotometric methods.     

Spectrofluorimetric Determination of Chlorpromazine Hydrochloride and Thioridazine Hydrochloride

Abstract

Fluorescence spectroscopy was applied to the development of a sensitive and simple method for the determination of chlorpromazine HCl and thioridazine-HCl. The method is based upon development of an intense fluorescence using N-bromosuccinimide as the fluorogenic reagent. The produced fluorescence has very characteristic excitation and emission spectra and was stable for at least one hour. The results were reproducible and as little as 5 ng/ml chloropromazine HCl and 1 ng/ml thioridazine-HCl could be determined. The method was applied successfully to the analysis of various commercially available dosage forms. The obtained results were in good agreement with those of the official BP 93 procedures.     

ELIMINATION OF THIOPHENOL FROM PHENYL ORTHOTHIOESTERS IN THE MASS SPECTROMETER AND NOVEL REARRANGEMENT OF KETENE THIOACETALS UPON ELECTRON IMPACT

Abstract

The mass spectra of four selected phenyl orthothioesters (1–4) have been measured. The obtained spectra revealed the conversion of the compounds (1–4) into ketene thioacetals (5–8) via the elimination of thiophenol in the mass spectrometer. The thermal nature of the process was confirmed and the mass spectra of ketene thioacetals (5–8) have been discussed. A novel fragmentation path for ketene thioacetals was suggested.     

Spectrophotometric Study of 1,2,7-Trihydroxyanthraquinone-Mg(II) Complex. Determination of Mg(II)

Abstract

The spectrophotometric study of violet complex Anthrapurpurin-Mg(II) in a basic medium and a hydroalcoholic solution was made (δ_max - 530 nm., ? = 3.5 × 10³ 1 mol^?1 cm^?1, stoichiometry 1:1, apparent constant of stability log K = 9. 26). A new method for the spectrophotometric determination of Mg(II) is proposed for concentrations between one and six ppm. Relative errors between replicate samples were 0.90 %.     

Supramolecular synthons and pattern recognition in adenine amides – synthesis,structures and thermal properties

An effective method for the synthesis of novel adenine amides was developed and successfully implemented, leading to 4-propyloxy-N-(9H-purin-6-yl)benzamide (1) and 4-dodecyloxy-N-(9H-purin-6-yl)benzamide (2). The compounds were fully characterised by means of spectroscopic (¹H NMR, ¹³C NMR, FT-IR) and thermal (TG, DSC) analysis. The crystallographic analysis revealed that the formation of supramolecular chains relies on hydrogen bonding between amide functionalities. All supramolecular synthons found in the crystal structure of 1 were confirmed with the temperature-dependent IR method. The temperature-dependent IR method is useful in determining supramolecular interactions for compound 2, for which the crystal structure could not be obtained. A detailed analysis of temperature-dependent FT-IR spectra was used for the first time to identify the hydrogen bonds that exist in the solid state of our compounds; it can therefore be considered a promising method for the pattern recognition of hydrogen bonding in supramolecular chemistry.