[The production of furocumarin in Apium graveolens L. and Pastinaca sativa L. after infection with Sclerotinia slcerotiorum]. / Untersuchungen zur Furocumarinbildung in Apium graveolens L. und Pastinaca sativa L. nach Infektion mit Sclerotinia sclerotiorum.

Roots of celery (Apium graveolens) and parsnip (Pastinaca sativa) were inoculated with Sclerotinia sclerotiorum. At the beginning of the infection it is recognized that the level of furocoumarins rises but decreasing in the further time. Trimethylpsoralene was detected neither dc nor hplc. Sclerotinia grows poorly in parsnip. In this the high level of furocoumarins prevents the growth of the fungus because the furocoumarins are fungistatic. Obvious Sclerotinia is able to stimulate the origin of furocumarins in genetic predestinated plants first at time which can explained as reaction against the infection. The infection cannot avail to arise the technical useful yield.

[The separation of some racemic beta-blockers and alpha-sympathomimetics with HPLC following derivatization]. / Zur Trennung einiger racemischer beta-blocker und alpha-Sympathikomimetika durch HPLC nach Derivatisierung.

Five beta-adrenergic blocking agents and two alpha-sympathicomimetics were separated after derivatization with (R)-(-)-1-(Naphth-1-yl)-ethylisocyanate (NEIC). For two of these analytes the separation was successful also after reaction with (R)-(+)-1-phenylethylisocyanate (PEIC) by using HPLC with RP-18 phases and a water-methanolic eluent by UV-detection on 254 nm. After reaction with (1S)-(+)-campher-10-sulfonylchloride (CSC) an acceptable separation of norphenylephedrine also was possible. Analytes which can be derivated with NEIC and PEIC give no reaction with CSC (and vice versa).

[Spectrophotometric analysis of the multicomponent system: dihydralazine sulfate, hydrochlorothiazide and reserpine]. / Untersuchungen zur spektrometrischen Analyse des Mehrkomponentensystems Dihydralazinsulfat, Hydrochlorothiazid und Reserpin.

With respect to their performance a computer aided spectrometric analysis of multicomponent system dihydralazine sulfate hydrochlorothiazide and reserpine was made under various conditions. To find out the advantageous measuring points the difference spectra were determined. The influence of the number of measuring points, the single and mixture calibration and the dimensiation of calibration matrix to accuracy and precision was investigated and the limits of the determination for the three component system are discussed.

[Ion pair-HPLC of a pharmaceutical multicomponent system]. / Ionenpaar-HPLC eines pharmazeutischen Mehrkomponentensystems.

A multicomponent system of non-ionic (methyl- and propylhydroxybenzoate) and ionic (theophylline, phenobarbital, atropine methobromide, demelverine hydrochloride) analytes, which are applied in therapy as bronchospasmolytically effective drug (Aminophyllin compositum tablets), was investigated by means of ion-pair-HPLC-technique on reversed phases. As ion-interaction-reagents (IIR) were tried alkylsulfonates and sodium cyclamate. The influence of some factors on retention was described. The use of "mixed" IIR for improvement of the separation was investigated.

[Ion pair-HPLC of some aromatic amino- and hydroxycarboxylic acids]. / Untersuchungen zur Ionenpaar-HPLC einiger aromatischer Amino- und Hydroxycarbonsäuren.

Various factors influencing the ion-pair-HPLC separation of some aromatic amino- and hydroxycarbon acids were described and discussed. Distinct effects of the ion pair formation of organic acids with quarternary alkylammonium salts (CTAB) are recognized on condition that the carboxylic group is not blocked by intramolecular H-bonding or partial betain structure. If the carboxylic group is unconnected the retention time increases depending on the pka of the acid with increasing pH if no complete ionization exists. In order to separate similar compounds at low retention time with distinct resolution an organic modifier of suitable strength and high selectivity have to be added to the mobile phase.

[The determination of clonidine by charge-transfer-complex formation with iodine]. / Bestimmung von Clonidin durch Charge-Transfer-Komplexbildung mit lod.

The donor clonidine (1) forms a charge-transfer-complex of stoichiometric composition 1:1 with the sigma-acceptor iodine. The association constant was determined by means of the Hildebrand-Beneshi equation being 38,000 l/mol. At first it forms an outer complex, characterized by charge-transfer band at 285 nm and the blue-shifted iodine band at 393 nm. From this complex the inner ionic complex results depending on time in which iodine iones arise reacting with unconnected iodine to triiodiones. These show absorptions at 291 and 364 nm. Resulting from it an assay of 1 worked out. The regression line is y = (4.370 +/- 0.256) x + (0.411 +/- 0.053), Srel = 1.3% (n = 10) and the linear range is placed between 0.01-0.25 mg/10 ml solution.

[The effect of micelle formation on the rate of arylation of various amino acids by 2,4-dinitrofluorobenzene]. / Uber den Einfluss von Mizellbildnern auf die Arylierungsgeschwindigkeit verschiedener Aminosäuren mittels 2,4-Dinitrofluorbenzen.

The micelle catalysis of cetyltrimethylammoniumbromide (CTAB), alconiumbromide (ABr) and benzalkoniumchloride (BCl) on the arylation of several amino acids by 2,4-dinitrofluorobenzene (DFB) was examined. Comparing the reaction rates (RGK) a graduation of the surfactants is observed with regard to their catalytic activity decreasing from ABr down BCl to CTAB respectively. The straight line shows the same ascent angle and are removed almost parallel against one another. Several amino acids react upon the influence of CTAB with DFB different. At the selected amino acids two groups are found. The reaction of tryptophane, tyrosine, proline and phenylalanine with DFB takes place with comparable velocity influenced by CTAB, whereas threonine, histidine and ornithine react with DFB somewhat or not at all.

[The micelle catalysis of cetyltrimethyl ammonium bromide on phenylalanine arylation by 2,4-dinitrofluorobenzene]. / Untersuchungen zur Mizellkatalyse des Cetyltrimethylammoniumbromids auf die Arylierung des Phenylalanins mittels 2,4-Dinitrofluorbenzen.

The reaction of phenylalanine with 2,4-dinitrofluorobenzene is increased by substances forming micells. As against the basic test, the increase is not dependent on conditions using solutions of 2.42 X 10(-3) mol phenylalanine and 1.62 X 10(-4) mol dinitrofluorobenzene the rate constant of the reaction proportionally increases by addition of 6.2 X 10(-4) to 4.4 X 10(-3) mol cetyltrimethyl ammonium bromide solution, then remains constant and finally decreases with further increase of the concentration. These curves could continuously be registered with varying pH values, although the basic and the catalytic reaction rate of both the reactions will increase according to the pH value with any buffer. A further increase of the basic and the catalyzed reactions can be enabled by increasing the temperature. The validity of the Arrhenius equation could be proved.

[HPLC studies on the distribution behavior of guanyl- and N-phenylguanylhydrazone derivatives]. / HPLC-Untersuchungen zum Verteilungsverhalten von Guanyl- und N-Phenylguanylhydrazonderivaten.

The article in hand presents first HPLC studies on the distribution behaviour of guanylic and N-phenylguanylic hydrazone derivates. The chromatographic parameters of compounds, which had been separated at NH2-columns by 0.06 mol X 1(-1) Na2HPO4 buffer/methanole (30 : 70), could be identified, and the k'/rates could be utilized for the calculation of the coefficient of distribution. As a result of performed calculations of the correlation, it could be proved that the log. P rates which had been ascertained by the HPLC method, been determined by the shaked flash method and been calculated acc. to Leo, correlate to the 1% significant level.

[The use of short-term tests for oxidation studies of drugs. 2. Kinetics of 2-mercaptobenzthiazole oxidation]. / Untersuchungen zur Anwendbarkeit des Kurzzeittestes für oxidationsempfindliche Pharmaka. 2. Mitteilung: Kinetik der 2-Mercapto-benzthiazoloxidation.

By the example of 2-mercapto-benzthiazole it has been ascertained how far the k25 value obtained by extrapolation from the Arrhenius equation corresponds with the k25 value of the long-term test. To record besides oxidation products the 2-mercapto-benzthiazole, a UV-spectrophotometric method has been produced. The isothermal short-term test has been performed at 50, 60, 70, 80 and 90 degrees C after identification of the temperature independence of the reaction mechanism and of the reaction rate pH dependence.

[Studies on the light transmittance of coloured plastic bottles for liquid pharmaceutical preparations. Part 43: Contributions to problems concerning the use of plastic containers for liquid pharmaceutical preparations (author's transl)]. / Untersuchungen zur Lichtdurchlässigkeit eingefärbter Plastflaschen. 43. Mitteilung1 : Beiträge zur Problematik des Einsatzes von Kunstsoffbehältern für flüssige Arzneizubereitungen.

To assess the light transmittance of coloured plastic bottles, studies were made using the photographic paper method and a spectrophotometric technique. According to its sensitivity between 400 and 500 nm, the photographic paper gives information as to this wavelength range, directional radiation and scattered light being covered. In contrast to this, the spectrophotometric method yields discriminating information on the wavelength range between 200 and 800 nm. Apart from a minimum transmittance up to 500 nm, the coloured plastic bottles should have a high transmittance greater than 700 to ensure high transparency. Of the dyes tested, Pigment Orange and Chromeophthal Brown give the plastic bottles light-protecting properties 4 years' storage, both of these dyes show changes in the light-protecting properties by which the light transmittance of plastic bottles coloured with them is increased. When these dyes are used in adequate concentrations, this increase in light transmittance will remain within allowable limits, provided direct solar radiation be avoided.

[Criteria for the use of the linear allothermal short-time test in predicting stability (author's transl)]. / Kriterien zur Anwendung des linearen allothermen Kurzzeittestes nach Zoglio zur Stabilitätsvorhersage.

Three selected model substances of varying activation energy (naphazoline, 109 kJ/mole; acetylsalicylic acid, 72 kJ/mole; and phenobarbital, 60 kJ/mole) were studied to determine the conditions under which the allothermal short-time test according to Zoglio (linear increase in temperature) will yield stability predictions which are consistent with those provided by the isothermal short- or long-time test. The error of the determination method should be less than or equal to 1%. It is advantageous to use for the calculation as many data as the analytical facilities will permit to obtain. The actual value for the respective temperature should differ from the desired value by < +/- 0.2%. The increase in temperature should be very slow 1-2 degrees C/h at best). This is particularly true for substances of low activation energy, because more the energy values calculated on the basis of the allothermal test differ from the isothermally determined values, the flatter is the curve provided by the arrhenius equation. The temperature range should be chosen as large as possible, from 30-90 degress C, and the experiment should be continued until at least a 10% decomposition is achieved. On calculating the collision factor A and the reaction-rate constant for any temperature, it has proved useful to continue the experiment isothermally at the final point of the allothermal test.