Substances and Groups of Compounds

Barbituric acid derivatives, history and applications 88PHA827. Benzodiazepine receptor ligands as drugs 89FES345. Coumarine-based antioxidants 88KFZ1438. 

Fluorinated heterocycles 87PHA73,87T3123 90FES1043, 90FES1137, 90YGK16. 

Hematoporphyrins as photosensitizers for photodynamic diagnostics and therapy of tumors 90WCH149. 

N-Heterocycles derived from hydrazinoacetic acids 90PHA1. N-Heterocyclic drugs, action on central serotonin receptors 87JMC1. Imidazo[2,l-b]thiazole derivatives 89KFZ206, 89KFZ801. 

Medicines derived from S- and N,S-heterocycles as well as from sul-fonylamides and sulfides of N- and N,O-heterocycles 87YGK536. Organoelement compounds as drugs 87PHA793. 

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Confronted with a chemical substance or group of compounds the reader has to consider the four potential categories of risk - inflammability, instability, toxicity and dangerous reactions resulting from contact with other substances and materiais. But procedure does not only relate to chemical substances. It concerns other materials (eg asbestos), and modes of operation and introduces most often a manipuiator . These processes occur in an environment which also can have significant role. 

Chloramphenicol 1 %, polysorbate 80 6 %, in water for injection has been suggested as an ophthalmic solution [95]. Other formulae have been given and some of these are collected in Table 6.10. A solution of the antibiotic has been prepared in 50% iV,iV-dimethylacetamide as an intravenous injection. N,N-dimethylacetamide is a hydrotropic substance, a group of compounds whose actions are discussed in Section 6.7. Different crystal forms of chloramphenicol palmitate are soluble to differing extents in solutions of polysorbate 60. A detailed study of the solubilization of chloramphenicol in cetomacrogol solutions has been reported by Rogers [98] Regdon-Kiss and Kedvessy [99] have studied the... 

It is the parent substance of a group of compounds which includes cytosine, thymine and uracil, which are constituents of nucleic acids and barbituric acid and its derivatives, which are important medicinally. 

These designed methods will allow hereinafter development of the high-performance remedies, using biologically active substances from Arctium lappa L. root. Identification of stmcture and quality contents allows to obtain correct prediction of phamiacological properties of this groups of compounds. Express method allows to make supply of medical herb raw material more rational. 

Indol, CgH N, is the mother substance of the indigo group of compounds. It exists in various essential oils including neroli oil and oil of jasmin flowers. It is a crystalline compound, melting at 52° and boiling at 253° to 254°. Its odour is powerful and disagreeable, being distinctly faecal in character. Its constitution is as follows —... 

Preparative planar chromatography is a very important step in the complicated procedures of isolation of group of compounds or pure substances from complex matrices. The method gives additional possibilities of using various adsorbents and eluent systems to achieve complete separation of stracmral analogs. The method also enables combining the various methods of sample application, plate development, and derivatization to achieve satisfactory separation of isolated plant extracts components. 

Historically, organic environmental pollutants were hydrophobic, often persistent, neutral compounds. As a consequence, these substances were readily sorbed by particles and soluble in lipids. In modern times, efforts have been made to make xenobiotics more hydrophilic - often by including ionisable substituents. Presumably, these functional groups would render the compound less bioaccumulative. In particular, many pesticides and pharmaceuticals contain acidic or basic functions. However, studies on the fate and effect of organic environmental pollutants focus mainly on the neutral species [1], In the past, uptake into cells and sorption to biological membranes were often assumed to be only dependent on the neutral species. More recent studies that are reviewed in this chapter show that the ionic organic species play a role both for toxic effects and sorption of compounds to membranes. 

The study of the properties of the elements shows that these substances fall into groups, the members of each of which are like one another, and form compounds which are similar. The examination of the properties and compositions of compounds has shown that similarity of properties is always accompanied by similarity of composition. Hence, the fact that certain elements are very closely allied in their properties suggests that these elements may also be allied in their composition. Now, to speak of the composition of an element is to think of the element as formed by the union of at least two different substances it implies the supposition that some elements at any rate are really compounds. 

Similarity between odors arises because dissimilar substances or mixtures of compounds may interact with receptors to create similar sensory impressions in the sensory centers of the brain. The group of musk fragrances (comprising macro-cyclic ketones and esters as well as aromatic nitro compounds and polycyclic aromatics) are, for example, compounds with similar odors but totally different structures [5, 6]. Small changes in structure (e.g., the introduction of one or more double bonds in aliphatic alcohols or aldehydes) may, however, alter a sensory... 

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