Prolonged-action preparation

Wollister, L.E. Studies of prolonged action medication. 11. Two phenothiazine tranquilizers (thoradizine and chlor-promazine) administered as coated tablets and prolonged action preparation. Curr. Pharm. Tlier. 1965. 6, 486-496. 

C. A typical aromatic amine. Best prepared by the prolonged action of concentrated ammonia solution at a high temperature upon anthraquinone-l-sulphonic acid in the presence of BaClj and by reduction of the corresponding nitro compound or by amination of the chloroanthraquinone. 

The procedure for preparing 6-hydroxynicotinic acid is also based on a method described by von Pechmann. 6-Hydroxynico-tinic acid has also been prepared by decarboxylation of 6-hy-droxy-2,3-pyridinedicarboxylic acid by heating 6-hydra-zinonicotinic acid or its hydrazide with hydrochloric acid by the action of carbon dioxide on the sodium salt of a-pyridone at 180-200 and 20 atmospheres by heating the nitrile of 6-chlo-ronicotinic acid with alcoholic sodium hydroxide or hydrochloric acid from 6-aminonicotinic acid and by the prolonged action of concentrated ammonium hydroxide on methyl cou-malate. ... 

A sulfanilamide drug of prolonged action, 2-p-aminobenzenesulfamido-4-methylpyiimidine (sulfomerazine 162), first prepared by Japanese chemists from acetacetic aldehyde in 82% yield (49JPJ447), ranks among practically valuable 2-amino-4-methylpyrimidine derivatives. Later, a synthesis of this product directly from l-methoxybut-l-en-3-yne (100°C, AcONa, AcOH, 3 h) in 64% yield has been developed (76MI1). 

As has been mentioned, preparation of esters of the C-17 hydroxyl group of selected progestins affords compounds with prolonged action. Similar chemical treatment of a corticoid would almost certainly lead to an ester of the sterically more accessible primary alcohol at C-21. In an interesting method for achieving esterification of the more hindered and less reactive tertiary 17-hydroxyl, prednisolone... 

Zervas48 through the catalytic reduction of 2,3,4,6-tetraacetyl-2-hydroxy-D-glucal, has recently been prepared by the reductive desulfurization of ethyl tetraacetyl-l-thio-/ -D-mannopyranoside (XL),47 a substance which has been obtained through the mercaptolysis of mannosidostreptomycin48 and may be prepared through the prolonged action of ethyl mercaptan and hydrochloric acid on D-mannose. 

TESTOSTERONE, LONG-ACTING For IM use only. Individualize dosage. In general, more than 400 mg/month is not required because of the prolonged action of the preparation. 

Biphasic insulin mixture of insulin preparations that provide for immediate and prolonged action... 

Thionyl Bromide, SOBr2.—This analogue of thionyl chloride is best prepared by the prolonged action of hydrogen bromide on thionyl chloride 3... 

Chlorine and bromine react with thiophene to give successively the halogenation products shown (70-73). The bromination can be interrupted at the intermediate stages monochloro and dichloro derivatives have been obtained preparatively by chlorination with MeCONHCl. Addition products are also formed during chlorination prolonged action (with Cl2-I2) gives the dihydrothiophene derivative (74 Z = S). Iodination (I2-HgO) results in mono- and di-iodothiophenes (70) and (71) (X = I) only. Substituted compounds are halogenated as expected, e.g. (75). 

A convenient method of preparing arsenic pentasulphide is to boil arsenic pentoxide with piperazine, when a solution is obtained which, by the prolonged action of hydrogen sulphide, yields the compound As2S5.3C4H10N2.3H2S if this is treated with cold dilute hydrochloric or acetic acid, crystals of arsenic pentasulphide are formed.6... 

Recently, both hirsutine (85) and dihydrocorynantheine (86) were found to be active when the effects of these compounds on the action potentials of sino-atrial node, atrium and ventricle tissues were studied with standard microelectrode techniques [65]. In sino-atrial node preparations, both compounds concentration-dependently increased cycle length, decreased the slope of the pacemaker depolarization, decreased the maximum rate of rise and prolonged action potential duration. Thus, it was for the first time shown that hirsutine and dihydrocorynantheine have direct inhibitory effects on the cardiac pacemaker. In atrial and ventricular preparations, both compounds concentration-dependently decreased the maximum rate of rise and prolonged action potential duration. Although stereochemically different, these two alkaloids exhibited no difference in their effects on various myocardial action potential parameters. Dihydrocorynantheine also displays potent a-adrenoceptor blocking activity, while hirsutine is inactive [66]. Experiments with ion channels indicate that the mechanisms for these two phenomena probably differ. The direct effects of hirsutine and dihydrocorynantheine on the action potential of cardiac muscle through inhibition of multiple ion channels may explain the negative chronotropic and antiarrhythmic activities of these two alkaloids. 

There have been several examinations of the structure of Nageli dextrin,405407 which is prepared by the prolonged action of acid on granular starch. In one study,405 there was separated from waxy maize a branched fraction that was resistant to pullulanase action. As this fraction contained some molecules having two branch points that were in close proximity, it was considered that this may have hindered hydrolysis, and that it could be of relevance to studies on the structure of the original amylopectin. 

Ammonium peroxides.—At —10° C. dry ammonia reacts with a solution of 98 per cent, hydrogen peroxide in absolute ether to form a crystalline precipitate of the formula NH OaH or (NH4)202)H202. It melts at 14° C., and is converted by the prolonged action of ammonia into an oil, (NH4)202, which solidifies at —40° C., begins to decompose about —10° C., and melts at —2° C. It readily loses ammonia, regenerating the parent substance, NB C H.1 A crystalline, hydrated form of the composition (NH4)2O2,2H2O2,]0H2O, has been prepared. Potassium hydroxide decomposes it, with formation of ammonia and potassium peroxide. 

Normal ammonium thiotungstate, (NH4)3WS4, is prepared by the prolonged action of hydrogen sulphide on a dilute solution of ammonium... 

In the last decade hollow spheres are extensively studied in the context of application as containers of prolonged action for substances of the different chemical nature dmgs, cosmetics, dye. A number of methods for preparation of microspheres with the sizes ranging from nanometers to micrometers and consisting of various materials are developed. Polyelectrolye capsules have been produced by sequential adsorption of oppositely charged polyelectrolytes, also known as Layer-by-Layer (LbL) assembly onto the surface of colloidal particles followed by core dissolution [1-2]. Most of the capsules applications imply their chemical or physicochemical modification by influence of the ionic strength [3], pH [3], temperature... 

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