Spotting drugs

If it is known that a drug must bind to a particular spot on a particular protein or nucleotide, then a drug can be tailor-made to bind at that site. This is often modeled computationally using any of several different techniques. Traditionally, the primary way of determining what compounds would be tested computationally was provided by the researcher s understanding of molecular interactions. A second method is the brute force testing of large numbers of compounds from a database of available structures. 

Compounds closely related to the sulfonamide antibiotics proved to be the first drugs effective against Mycobacterium leprae, the causative agent of the disease known since antiquity, leprosy. These drugs are at least partly responsible for the decline of I hose horror spots, the leper colonies. 

This drug may cause spontaneous abortion. Women of childbearing age must use a reliable contraceptive If pregnancy is suspected, discontinue use of tiie drug and notify the primary health care provider. Report severe menstrual pain, bleeding, or spotting. 

A TLC method was developed for the estimation of nieotinie aeid and nicotinamide (Fignre 10.7) in phatmacentical preparations containing other vitamins, enzymes, herbs, and drugs, etc. [16]. The percentage recoveries for nicotinic acid and nicotinamide were 100.1 + 1.9 and 100.2 1.5, respectively, with this system. Each alcohol extract of samples or standard was pnt on sihca gel TLC plates, which were developed with distilled water. Each silica gel spot visualized under UV lamp was collected and extracted with 0.1 mol/1 HCl. The optical density of each clear extract was measured at 262 run. 

Qian et al. [46] determined miconazole nitrate and benzoic acid in paint by a thin-layer chromatographic densitometric method. The drug was spotted on a GF254 silica gel plate, developed with a 42 21 13 5 w-hexane-chloroform-methanol-... 

Zheng and Sun [67] used a thin-layer chromatographic method for the analysis of primaquine and other quinoline derivatives. The drug and other compounds were chromatographed on silica gel GF254 plate, with methanol aqueous 25 28% ammonia (200 3) and chloroform dichloromethane diethylamine (4 3 1), as mobile phases. Spots were located under ultraviolet radiation. The detection limit was 12 pg/mL. Total separation could be achieved by the use of two plates and the respective mobile phase. 

The Rf value for dobutamine hydrochloride when chromatographed on a silica gel 60 F254 thin layer plate developed by ethyl acetate/n-propanol/water/acetic acid (100/40/15/5 v/v/v/v) in an unsaturated chamber is about 0.67. The spot of the drug may be visualized under short wavelength UV light (254 nm), or under white light after exposure to iodine vapors. 

Modras (51) reported spot test reactions to differentiate hydralazine from closely related drugs. Reagents used were aqueous copper (I) chloride, aqueous ammonium molybdate, iodine in potassium iodide solution, aqueous cobalt (II) nitrate, alcoholic ninhydrin, and alcoholic bromophenol blue. The tests were performed on paper or on Silica Gel G. 

Another way that professionals assess for psychiatric disorders is to use an inventory that assesses for personality characteristics. The most famous of these inventories is the Minnesota Multiphasic Personality Inventory (MMPI), which is now in its second edition as an instrument. Although the MMPI is actually a personality inventory, as it names suggests, many professionals will use it to spot suspected psychiatric disorders, such as depression, Bipolar Disorder, Schizophrenia, and Anxiety Disorder. The MMPI has several scales to assess common personality traits, such as depression, mania, psychopathic deviance, and even alcohol and drug use (Weed, Butcher, McKenna, Ben-Porath, 1992). 

A 2-Dimensional experiment is done to determine if there are any TLC artifacts, or what are known as TLC procedure-related effects. In this study, a spot of drug substance at nominal concentration, usually 25 mg/ml, is placed on the HPTLC plate by making one spot by overlaying 3 applications of 5 pi each. This yields one tight spot that contains 15 pi of drug substance solution, rather than a large spot that pools by performing one application. The HPTLC plate is then developed in the usual manner and dried. The plate is then rotated 90° and a second... 

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