Action commercial preparations

Mechanism of Action. Commercial preparations of immune globulin mimic the normal role of endoge-... 

The endo-action of the K. marxianus PG was demonstrated by a extremely rapid attack on plant tissue. This activity appears to be at least equivalent to that of several commercial preparations used for separating plant cells for protoplast preparation (RMC, unpublished data). Most of the endo-PGs produced by plant pathogens and saprophytes have so far been reported to possess macerating activity. PG secreted by K. marxianus CCT 3172 also had a strong activity in reducing the viscosity of cocoa pulp. Cocoa pulp generally contains 1 - 1.5% (w/w) of pectin consisting of 68% esterification and 11.6% methoxyl content [18]. 

The many available types of laxatives are usually classified by their apparent mode of action.22 27 35 Often, two different laxatives, either from the same class or from two different classes, are combined in the same commercial preparation. Some of the more common laxatives, listed by their apparent mechanisms of action, are in Table 27-4. The major laxative classes and rationales for their use are outlined in the next few sections. 

Marijuana was first mentioned as a medicine in an American medical text in 1843 and in 1854 was listed in the U.S. Dispensatory. The latter year also marked the first written description by Bayard Taylor in The Atlantic Monthly of cannabis intoxication. In the 1850s, recommended medical uses for marijuana included the treatment of gout, rheumatism, tetanus, opiate and alcohol withdrawal, loss of appetite, dysmenorrhea, convulsions, depression, insanity, and asthma. Although its suggested uses were widespread, marijuana never actually achieved popular use in the medical community. The reasons for this include variations in potency of commercial preparations, variability in patients responses, slow onset of oral action, and lack of solubility preventing administration by injection. However, the drug was included in many patent medicine preparations and was officially recognized as a medicine in the U.S. Pharmacopoeia until 1937. In 1937 there were 28 pharmaceuticals that contained cannabis. 

Already familiar is the convenient laboratory preparation of elementary hydrogen by reduction of acids. Generally those metals lying between magnesium and tin in oxidation potential are appropriate. Less convenient but more spectacular is the production of hydrogen from action of the alkali metals on water. For small quantities of hydrogen, reaction of metal hydrides with water has been used such hydrides will be considered later in the chapter. Commercial preparations of H2 by reduction of steam with iron or coke and, finally, by the electrolysis of water should be recalled. 

Dialkylaminoethyl bromide hydrobromides have been known for many years. However, the standard method of preparation requires large volumes of hydrobromic acid.2 The less expensive analogous chlorides are preferred since their preparation is simpler and their reactivity is sufficient for the synthesis of well-known drugs.3 Ordinarily j3-dialkylaminoalkyl chloride hydrochlorides are prepared in good yield by treatment of /3-dialkyl-aminoalkanols with an excess of thionyl chloride in chloroform or benzene.4 An article on the German commercial preparation of Atabrine refers to the action of thionyl chloride on /J-diethyl-aminoethanol hydrochloride without solvent.5... 

Various colloidal systems have been studied for use as potential ophthalmic delivery systems, including liposomes and nanoparticles. Liposomes are bioerodible and biocompatible systems consisting of microscopic vesicles composed of lipid bilayers surrounding aqueous compartments. Liposomes have demonstrated prolonged drug effect at the site of action but with reduced toxicity. Ophthalmic studies have included topical, subconjunctival, and intravitreal administration, but no commercial preparations are currently available for ophthalmic use. 

Irradiation of PP in air leads to oxidative degradation, evidenced by discoloration and embrittlement. The extent of the degradation depends on crystallinity, MW, MWD, and chain mobility [Kadir et al., 1989 Kashiwabara and Seguchi, 1992 Williams, 1992]. Neat PP does not discolor on irradiation up to 100 kGy [Williams, 1992]. The antioxidants should be selected so as not to cause the discoloration. However, most commercial preparations containing phenolic antioxidants turn yellow on irradiation. Phenolic antioxidants produce stable phenoxyl radicals that convert into colored quinonoids. Other stabilizers and antioxidants are compounds that contain either phosphorous [Bentrude, 1965 de Paolo and Smith, 1968], sulfur [Jirackova and Pospisil, 1979], or hindered piperidine derivatives [Carlsson, et al., 1980 Felder et al., 1980 Allen et al., 1981]. A comprehensive list of stabilizers and their mode of action was given by Dexter [1992]. It is noteworthy that antioxidants and stabilizers are excluded from the crystalline regions [Winslow et al., 1966] thus they would provide protection only within the amorphous domains. 

The monoalkyl ethers with R = CHj, CjHj and C4H, , known respectively as methyl ceUoaolve, ceUosolve and hutyl cellosolve, are of great commercial value, particularly as solvents, since they combine the properties of alcohols and ethers and are miscible with water. Equally important compounds are the carbitols (monoalkyl ethers of diethyleneglycol) prepared by the action of ethylene oxide upon the monoethers of ethylene glycol ... 

Trimethylene dibromide (Section 111,35) is easily prepared from commercial trimethj lene glycol, whilst hexamethylene dibromide (1 O dibromohexane) is obtained by the red P - Br reaction upon the glycol 1 6-hexanediol is prepared by the reduction of diethyl adipate (sodium and alcohol lithium aluminium hydride or copper-chromium oxide and hydrogen under pressure). Penta-methylene dibromide (1 5-dibromopentane) is readily produced by the red P-Brj method from the commercially available 1 5 pentanediol or tetra-hydropyran (Section 111,37). Pentamethylene dibromide is also formed by the action of phosphorus pentabromide upon benzoyl piperidine (I) (from benzoyl chloride and piperidine) ... 

Titanium tetrafluoride may be prepared by the action of elemental fluorine on titanium metal at 250°C (5) or on Ti02 at 350°C. The most economical and convenient method is the action of Hquid anhydrous HF on commercially available titanium tetrachloride in Teflon or Kynar containers. Polyethylene reacts with TiCl and turns dark upon prolonged exposure. The excess of HF used is boiled off to remove residual chloride present in the intermediates. 

Fluorinated Heterocyclic Compounds. HeterocycHc compounds containing the CF group are prepared by methods similar to those used in the fluorination of aHphatic compounds. The direct action of fluorine on uracil yields the cancer chemotherapy agent, 5-fluorouracil [51-21-8] as one special example of a selective fluorination on a commercial scale (25). 

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