High Pressure Liquid Chromatographic Analysis and Dissolution of Famotidine in Tablet Formulation

Abstract

A reversed phase high pressure liquid chromatographic method was developed for the quantitation of famotidine in tablet formulation using a mobile phase consisting of 0.1M phosphate buffer (84%), acetonitrile (11%) and methanol (5%) at a pH of 6.5. The detection wavelength was set at 285 nm. The method is precise and adaptable for quality control purposes. The use of the analytical method hi studying tablet dissolution is described.     

Determination of the Components of the Boll Weevil Pheromone with a High Pressure Liquid Chromotographic Method

Abstract

A high pressure liquid chromatographic method was developed to separate the 4 components of the pheromone of the boll weevil. Minimum detectable amounts with 3.5% tetrahydrofuran in hexane was 10 ng for (+)-cis-2-isopropenyl-1-methyl-cyclobutaneethanol, 1 ng for (Z)-3,3-dimethyl-Δ¹,α-cyclohexaneethenol, and 2.5 ng each for (Z)-3,3-dimethyl-Δ¹,α-cyclohexaneacetaldehyde and (E)-3,3-dimethyl -Δ¹α-cyclohexaneacetaldehyde at 214 nm.     

High Performance Liquid Chromatographic Procedure for Retinoic Acid in Ophthalmic Solution

Abstract

A fast and simple procedure has been developed for the quantitation of retinoic acid in ophthalmic solutions. the procedure involves the use of reverse phase high performance liquid chromatography with a mobile phase containing an amine modifier. This procedure is specific for retinoic acid in the presence of its degradation products and formulation excipients. the method is linear over a wide range of concentrations.     

Pheromone, 2. Mitt. Ein Verfahren zur Herstellung von Ketonen und Spiroketalen durch Entschwefelung von Thienylethern

Summary Starting from substituted methoxythiophenes1 ketones and spiroketals can be synthesized in one step by desulfurization with partial hydrogenation. The bark beetle pheromone chalcogran2 a and the wasp anti aggression pheromone2 b were prepared by this method.

Prof. Dr. F. Sauter zum 60. Geburtstag gewidmet     

High Performance Liquid Chromatographic Determination of Trimethoprim and Sulphadiazine in Medicated Fish Feedstock

Abstract

A high performance liquid chromatographic (HPLC) method for the determination of sulphadiazine and trimethoprim in medicated fish feedstock is described. It is based on the extraction of the drugs into methanol followed by separation on a μ-Bondapak column using an aqueous acetonitrile mobile phase of pH 3.0. The method was validated by determining intra- and inter-assay precision and the coefficient of variation was found to be less than 8% for both drugs. Callbration curves were linear over the range 160–4000 pg drug per g of feedstock and the method was applied to the determination of a commercial feedstock formulation.     

Investigation of terminal olefine in the isothiocyanatotolane liquid crystals with alkoxy end group

Three series of liquid crystals based on isothiocyanatotolane core with terminal alkenoxy groups (4A-1?4C-2) have been synthesised via multi-step reactions. Their thermotropic mesophases and physical properties are evaluated by comparison with the alkoxyl analogues (4a-1?4c-2). The results show that the isothiocyanatotolane LCs with alkenoxyl terminals deliver higher birefringence (0.410~0.436), lower melting points, lower melting enthalpies and viscosity. The effects of the alkenoxy terminal groups and the lateral fluoro substituents on the mesomorphic behaviour and physical properties are discussed. The formulation of the mixture containing isothiocyanatotolane liquid crystals with alkenoxyl terminals provides evidence of an useful candidate for liquid crystal photonics.     

The Determination of Sodium Monofluoroacetate (Compound 1080) in Formulation and Technical Samples by High Pressure Liquid Chromatography

Abstract

A high pressure liquid chromatographic (HPLC) procedure was developed for the determination of sodium monofluoroacetate (Compound 1080). The procedure utilized an amine (NH₂) bonded column for the reverse phase determination of sodium monofluoroacetate in formulation and technical samples.     

Eigenvalues of propagation through liquid crystals

Abstract

Analytical expressions are given for the propagation constant through an homogeneous liquid crystal, following the 4 × 4 matrix formulation of Berreman. Also propagation through polarizers can be calculated analytically; it is a special case of a situation described by Teitler and Henvis.     

Using dextromethorphan potentiometric membrane sensor in analysis of dextromethorphan hydrobromide in pharmaceutical formulation and urine; Computational study

Dextromethorphan (DXM) is an antitussive (cough Hyj/UA suppressant) drug found in many cough medicines. Dextromethorphan has also found other uses in medicine, ranging from pain relief to psychoactive applications. In this study, a potentiometric liquid membrane sensor for simple and fast determination of dextromethorphan hydrobromide in pharmaceutical formulation and urine was constructed. For the membrane preparation, DXM-tetraphenylborate complexes were employed as electroactive materials in the membrane. The wide linear range (10⁻⁶–10⁻² M), low detection limit (1 × 10⁻⁶ M), and fast response time (∼5 s) characterize the proposed sensors. Validation of the method shows suitability of the sensors for applications in the determination of dextromethorphan hydrobromide in pharmaceutical formulation and urine.     

High Performance Liquid Chromatographic Assay of Verapamil Hydrochloride in Dosage Formsk

Abstract

A stability indicating high-performance liquid chromatographic (HPLC) method for determining verapamil hydrochloride in dosage forms is described. The assay affords baseline separation of the drug from its synthesis impurities and from photolytic degradation products, as well as from formulation excipients. The drug was extracted in 0.05 N hydrochloric acid, chromatographed on a C₁₈ reverse-phase column, eluted with methanol-water-acetic acid-triethylamine (55:44:1:0.1) and the effluent was detected at 280 nm. Linearity studies were carried out using peak height or peak area measurements and the detector response to the concentration of verapamil hydrochloride was confirmed. Excellent interlaboratory precision and recovery data were obtained by the spiked placebo method. This procedure was rapid and selective for the assay of the cardiotonic drug. Application of the method for the assay of verapamil hydrochloride in representative dosage forms is described.     

Cyclodextrin Bonded Phase for Liquid Chromatographic Separation and Analysis of Some Oral Contraceptives

Abstract

A specific and sensitive analytical HPLC procedure was described for quantitative determination of ethinylestradiol and norethisterone acetate (Anovlar 1) and ethinylestradiol and norgestrel (Primovlar) in tablet formulation. These steroids were extracted from the tablets with methanol. The steroids were then determined with high performance liquid Chromatograph-Cyclobond 1 column using mobile phase phosphate buffer pH 7.0: methanol (60:40), flow rate 0.5 ml min^?1 and the detection was effected spectrophotometrically at 280 nm, using variable wavelength UV detector.

There was > 99.3% recovery from synthetic mixtures and the coefficient of variation was < 2.0% for the formulations investigated. The method is highly quantitative and reproducible.     

昆虫信息化合物相对蒸气压的气相色谱分析

报道了用０１２％胆固醇对氯肉桂酸酯（ＣＰＣＣ）和００８％ＯＶ１０１液晶相毛细管柱气相色谱法测定化合物相对蒸汽压的方法及对６０个昆虫信息化合物相对蒸汽压的测定结果。由此可直接利用公式计算昆虫信息素各组分的释放速率。使合成信息素最佳配比的选择方法大为简化。     

A Short Formal Synthesis of (-)-Serricornine

A short and efficient formal synthesis of serricornine (1), the sex pheromone of Lasioderma serricorne F., is described. The homochiral aldol 5 is straightforwardly converted to tosylate 9 to give homochiral lactone 2a (6 steps, 22% overall yield from oxazolidinone 4), a known precursor of (-)-1.     

Enantioselective Synthesis of Ipsenol and Ipsdienol Using a (2-Bromoallyl)borane Derivative

(S)-(-)-Ipsenol (2b) and (S)-(+)-ipsdienol (4b), a major component of the sex pheromone of the bark beetle, and their enantiomers (3b and 5b) were prepared enantioselectively using tartrate esters of (2-bromoallyl)boronic acid in the key step.

     

Chemical Recycling and Liquefaction of Rigid Polyurethane Foam Wastes through Microwave Assisted Glycolysis Process

Glycolysis of polyurethane rigid foams (PUFs) was performed utilizing microwave irradiation at atmospheric pressure. The effects of various metal hydroxide and acetate catalysts as well as different microwave powers were investigated. All reactions were monitored by FTIR spectroscopy. The recovered liquid product containing OH functional groups was applied as a portion of the polyol in formulation of a new polyurethane rigid foam product. The reactivity factors and densities were compared with the foam produced from totally virgin polyol.     

A Model of Resonance Scattering in Liquid Na[sbnd]Pb Alloys

Abstract

The curve of the electrical resistivity of liquid Na[sbnd]Pb alloys has a large maximum around the composition of Na₄Pb corresponding to a minimum value of the concentration-concentration fluctuation in the long wavelength limit, S_cc (0). The maximum in the resistivity curve is interpreted in terms of a resonance scattering of the conduction electrons by the short range ordered ‘complex’, based on the t-matrix formulation and with the help of thermodynamic data of these alloys.     

Stereospecific Synthesis of (2E,13Z)‐2,13‐Octadecadienyl Acetate,the Sex Pheromone Component of the Lepidoptera Species

The main component of the sex pheromone of many lepidopteran pests, (2E,13Z)‐2,13‐octadecadienyl acetate (1), has been synthesized following a simple route using 12‐(2‐tetrahydropyranyloxy)‐1‐dodecyne (2) as the starting material.     

On the Effect of Diene Geometry in Intramolecular Allyl Cation Cycloadditions

Attempted intramolecular allyl cation cycloaddition of trienol 2a, which contains a conjugated diene of Z-configuration, affords monocyclic trienes 3a,b, in contrast to related trienols known to produce [5,5]-bicyclic and/or [5,7]-bicyclic products. Cyclopentyl trienes 3a,b are isomeric with multifidene, an algal pheromone. Dimethyl trienol 6 fails to cyclize (under identical conditions), but eliminates to yield tetraene 7.     

GLC and HPLC Determination of Diazepam and its Degradation Products in Pharmaceutical formulations

Abstract

Stability-indicating high performance liquid chromatographic (HPLC) and gas-liquid chromatographic (GLC) assays for diazepam in pharmaceutical formulations are described. In HPLC method, the material is extracted with 5 % aqueous methanol and chromatographed on a dimethyloctyl stationary phase using methanol-water-acetic acid (80: 20: 1) and propyl paraben internal standard. The system separated diazepam from the main degradation products, desmethyl diazepam (a synthetic precursor of diazepam) and the excipients present in ampoules and syrups. The GLC method included the extraction of diazepam and 2-methylamino-5-chiorobenzo-phenone (MACB) from aqueous acidic solution into chloro form leaving the other degradation products in the aqueous phase. The chloroform extract is evaporated to dryness, dissolved in chloroform containing diethylhexyl phtha-late as internal standard and chromatographed on an OV-17 stationary phase using flame ionisation detector. The results are compared with the BP method described for each formulation.     

Kalidoss—Jacobson Free Length Theory Applied to Binary Liquid Mixtures of CCI4+Toluene/Aniline/oCresol m-cresol p-Cresol

Abstract

Ultrasonic velocities and intermolecular free lengths in binary liquid mixtures of CC4 with toluene, aniline, o-cresol, m-cresol and p-cresol have been calculated theoretically, at different compositions and at temperature 298 K, based on Free Length Theory as revised recently by Kalidoss. It is observed that there is a close agreement of calculated velocities with experimental ones. The shape and thermostatic state picture built up in this formulation could be considered as a good representation of molecular state.