Sci. Pharm., Volume 73, Issue 4 (December 2005) – 5 articles , Pages 173-262

The naphthoquinone levels in clones of the sundew species Drosera communis, D. madagascariensis, D. peltata and D. rotundifolia were determined under in vitro, green house, and outdoor growth conditions. D. rotundifolia revealed a lower naphthoquinone content in vitro which rose upon transfer ex vitro. D. communis and D. madagascariensis exhibited higher levels in vitro which decreased in the greenhouse and further under outdoors conditions. Decreased naphthoquinone levels were found in D. peltata when in vitro cultures were moved to the greenhouse, which increased again when the plants were cultivated outdoors. The results underline that in the cultivation of the medicinally useful carnivorous genus Drosera species-specific differences in the biosynthesis of secondary metabolites under different environmental conditions have to be taken into consideration. Full article

Epidermal characters of nine of the Central European Equisetum species were documented using both scanning electron and light microscopy. The arrangement of silica pilulae on the subsidiary cells of stomata as well as the type and the arrangement of papillae on the ridges of main stems and branches allow an unambiguous identification of the species even in the powdered state. A key for the identification is presented, and recommendations for an improved text for the monograph in the European Pharmacopeia are given. Full article

Two simple and sensitive colorimetric and atomic absorption spectrometric procedures have been established for determination of hyoscine N-butylbromide (Hyo.Br) in pure form and in pharmaceutical formulation. The methods are based on formation of an insoluble coloured ion-associate between the examined drug and tetrathiocyanatocobaltate (CoTC) or hexathiocyanatochromate (CrTC). The first method involves extraction of Hyo-CoTC and Hyo-CrTC ion-associates with methylene chloride and isobutyl alcohol, followed by measuring the absorbance at 630 and 557 nm, respectively. Optimization of the extraction conditions is investigated. Beer's law is obeyed in the concentration ranges 144.20-865.20 and 72.00-640.00 μg/ml using CoTC and CrTC, respectively. The molar absorptivities, Ringbom ranges, Sandell sensitivities and quantification and detection limits are also calculated. The second method is based on measuring the absorbance of the excess cobalt or chromium in the aqueous solution, after precipitation of the drug, at 240.7 and 357.9 nm using atomic absorption spectrometer, respectively. Linear application ranges, characteristic concentrations and detection limits of Hyo.Br are 0.404-1.617 mg/ml, 16.11 and 10.78 μg/ml in the case of CoTC, while 0.040-0.283 mg/ml, 29.50 and 2.70 μg/ml in the case of CrTC. The present methods have been successfully applied for the determination of the drug in commercial dosage form. The data obtained by the developed methods are compared with the official one. Full article

The coumarin-3-cinnamoyl derivatives 2a-d were prepared via Claisen-Schmidt condensation of 3-acetylcoumarin 1 with different aromatic aldehydes. Cycloaddition reaction of 2b,e with guanidine and thiourea yielded the corresponding aminopyrmimidine 3a,b and thioxypyrimidine derivatives 4a,b, respectively. Compounds 4a,b were condensed with chloroacetic acid or 3-bromopropionic acid to yield coumarin 3-thiazolo-pyrimidine 5a,b and thiazinopyrimidine 6a,b derivatives, respectively. Compounds 4a,b were condensed with chloroacetic acid and aromatic aldehyde to yield the aryl methylene derivatives 7a,b which could be prepared directly by condensation of compounds 5a,b with aromatic aldehydes. Compounds 2a-e were condensed with malononitrile or ethyl cyano acetate in presence of ammonium acetate to yield cyanopyridine 8a,b and cyanopyridone 9a-d derivatives, respectively, which were prepared by condensation of 3-acetylcoumarin 1, malononitrile or ethylcyanoacetate and aromatic aldehydes in presence of ammonium acetate. Condensation of compounds 2a,b,e with o-phenylenediamine in refluxing ethanol led to the formation of 10a-c as intermediate, followed by cleavage by thermolysis to benzimidazole derivative 11 along with compounds 12a-c as mixture, which were obtained directly by fusion of a,&unsaturated ketones 2 with ophenylene diamine at 200-220°C, while compound 11 could be prepared in pure form by fusion of 1 with o-phenylene diamine at the same temperature. The pharmacological screening showed that many of these obtained compounds have good antidepressant activity comparable to Tranylcypromine® as reference drugs. Full article

New Plastic membrane ion-selective electrode for trimetazidine dihydrochloride based on trimetazidinium-tetraphenylborate was prepared. The electrode exhibited mean calibration graph slope of 29.5 mV per decade of (TrimCl₂) concentration at 25°C. The electrode can be used within the concentration range 3.2×10^-5-10^-2 M (TrimCl₂) at pH ranges of 1.5-3.8 and 4.5-7.5. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode, which was (0.00088 V°C^-1). The electrode showed a very good selectivity for (TrimCl₂) with respect to a number of inorganic cations, sugars and amino acids. The electrode was applied to the potentiometric determination of the trimetazidine ion and its pharmaceutical preparation under batch and flow injection conditions. Graphite coated wire was prepared and characterized as sensor for the drug under investigation. Also, trimetazidine was determined by conductimetric titrations. Full article