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Biomedical subjects

R Kaliszan

Publications and source records attributed to R Kaliszan.

At least 55 records · Page 3Linked to original sources
PubMed1985

Effect of imidazoline drugs on human blood platelet aggregation.

The effect of seven commonly used in therapy imidazoline derivatives on human blood platelet aggregation was studied. Three of the agents, i.e. clonidine, antazoline and tetryzoline were classified as partial agonists of the receptor responsible for aggregation. Two other drugs, i.e. phentolamine and tolazoline act as competitive antagonists of relatively high receptor affinity. The remaining imidazolines: xylometazoline and naphazoline effectively inhibit the platelet receptor in a non-competitive manner. The last two compounds seem to be selective alpha 2-adrenoceptor antagonists.

Adrenergic alpha-Agonists↗
PubMed1985

Analgesic activity of new pyrazine CH and NH acids and their hydrophobic and electron donating properties.

Analgesic efficacy was determined by the hot plate method for a group of 17 new pyrazine and 3 non-pyrazine CH and NH acids. The biological data were quantitatively related to the hydrophobicity of the compounds, expressed by fragmental constant, and to the orbital energy of the highest occupied molecular orbital, calculated quantumchemically. It has been found that the higher the electron donating properties, the more active is the agent, provided that its hydrophobicity allows it to reach its site of action. The results obtained support the charge transfer model for the biological interaction of analgesic agents.

Amides↗
PubMed1985

Structure and alpha-adrenergic activity of pyrazinimidazolines.

The effects of newly synthetized pyrazinimidazolines on the contraction of isolated rat tail artery and on the chronotropic action of rat atria as well as the effects on blood pressure in anaesthetized rats were determined. The structure-activity relationships were studied, including standard imidazoline drugs. Starting from practically inactive derivatives the step-by-step structural modifications have been made resulting in markedly active chemical congeners, which were designed, synthetized and tested pharmacologically.

Animals↗
PubMed1984

High performance liquid chromatography as a source of structural information for medicinal chemistry.

The methods of generating physicochemical data related to the changes in structure of solutes by means of high performance liquid chromatography (HPLC) are reviewed from the point of view of quantitative relationships between chemical structure and biological activity. The information obtainable from retention data are discussed in categories of the specific molecular interactions involved and in thermodynamic terms. The advantages and limitations of the approaches directly relating bioactivity and capacity factors are also considered. The present and potential usefulness of HPLC for medicinal chemistry is demonstrated.

Chemical Phenomena↗
PubMed1982

Structure-olfactory activity relationship in a group of substituted phenols.

Using phenol as the standard relative olfactory thresholds have been determined for a series of substituted phenols in experiments with 8--10 human subjects. Significant relations have been obtained describing the activity as a square function of the hydrophobicity parameter corrected for ionization. Chromatographic measurement of phenol polarity has been proposed based on retention indices determined on phases of different polarity. The human sense of smell system has been discussed as a model for studies on drug-receptor interactions involving the living organism as a whole.

Chemical Phenomena↗
PubMed1981

Chromatography in studies of quantitative structure-activity relationships.

The rational bases, experimental techniques and conditions required for the chromatographic determination of the structural data of importance for studies on quantitative relationships between chemical structure and biological activity of drugs (QSAR) are reviewed. Practical applications of the information gathered from various chromatographic modes in correlation with bioactivity data are discussed.

Animals↗
PubMed1979

In vitro activity of sulphonamides as a function of their molar refractivity.

A significnat correlation has been found between the in vitro activity of 16 commonly employed sulphonamides and their molar refractivity. The molar refractivity has been shown to be a superior parameter for the description of the activity of sulphonamides than the sum of electronegativities of atoms making up a heterocyclic substituent in the sulphonamide molecule and molecular weight of the substituent.

Bacteria↗
PubMed1976

Studies on the polymorphism of barbital.

Crystalline samples of barbital obtained by isothermal crystallization from various solvents or by sublimation were analysed. Morphological, thermomicroscopical, thermal, IR, density and initial dissolution rate studies were carried out. X-ray analysis according to Debye-Scherrer was realised after 9-month storage of samples at room conditions. The ability of barbital to form polymorphic modifications was confirmed but the conclusions of previous works were discussed. It was found that the stability of metastable crystal structures II, III and IV was high enough to make them commercially feasible.

Barbital↗
PubMed1976

Studies on the polymorphism of carbromal.

Specimens of carbromal obtained by crystallization from various solvents were analyzed. After a 9-month storage period, the occurrence of three polymorphic forms (I, II and III) was ascertained. The metastable form III obtained by crystallization from dimethylformamide showed a reasonably high stability. Preliminary pharmacological tests revealed clear-cut differences in the therapeutic effect between a commercial specimen and the polymorphic modification III. The results presented here indicate the importance of polymorphism of carbromal for medicinal use.

Animals↗