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Detection And Identification of Drugs of Dependence
Published in S.J. Mulé, Henry Brill, Chemical and Biological Aspects of Drug Dependence, 2019
Quantitative methods for the narcotic analgesics and, in particular, morphine were developed primarily for the colorimetric estimation of these drugs following extraction from biological materials. The organic extract was usually mixed with the dye which forms a complex with the basic compound. The dye was then extracted into acid in proportion to that complexing with the drug. The acidic dye method was used most successfully with narcotic drugs34 by application of the dye methyl orange originally developed for organic bases.3,5 Other dyes used in this manner are bromcresol green, bromcresol purple, and bromthymol blue. Coupling the drug with diazonium salts was used successfully with morphine36 and organic bases.37 In all cases, the final colored product was estimated by spectrophotometry. The major difficulties with these techniques were specificity and sensitivity. Some specificity may be imparted to the reaction by subjecting the extracts to column or thin-layer chromatography prior to preparation of the color complex.
Scintillation Counting
Published in Graham Lappin, Simon Temple, Radiotracers in Drug Development, 2006
Some laboratories will operate on very few quench curves, with perhaps one for each scintillation cocktail in use. Others will have a plethora of quench curves covering every scintillation cocktail, vial and sample type. When, therefore, are quench curves genuinely required? Clearly there should be different quench curves for each radioisotope. The other major factor is the scintillation cocktail, or to be more precise, the solvent in the cocktail. Is it necessary to construct quench curves for chemical and color quench? In general, scintillation counters will deal with the issues of color influence in quench correction. However, there are many documented instances of quench correction sets that contain both chemical and color quenchers. A common color quencher is methyl orange, which will account for both color and chemical quench. If colored samples are being analyzed, it is probably worthwhile to develop suitable quench curves, although it is better to avoid colored samples in the first place (see Chapter 9).
Ultraviolet and Light Absorption Spectrometry
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Zoltan M. Dinya, Ferenc J. Sztaricskai
Sanghavi and Katdare [218] first hydrolyzed erythromycin with concentrated hydrochloric acid followed by treatment with benzaldehyde in acetic acid to obtain a Schiff base exhibiting absorption at 490 nm. In these quantitative measurements another antibiotic, such as penicillin, neomycin, or streptomycin, did not interfere, but the presence of tetracyclines disturbs the determinations. Later, benzaldehyde was replaced by p-dimethylaminobenzaldehyde and the measurements were achieved at 488 nm [219]. Amer et al. [220] estimated the erythromycin content of pharmaceutical preparations on the basis of the absorbance at 386 nm of a yellow product formed on treatment with salicylaldehyde in ethanol. Smith et al. [221] elaborated a colorimetric assay method for the chloroform-extractable complexes of erythromycin with sulfonic acid dyes (such as methyl orange). It has been shown by Bhathar and Madkaiker [200] that erythromycin also forms a complex with bromothymol blue at pH 3.5, which is extractable with chloroform and exhibits specific absorbance at 415 nm. Among several sulfophthalein acid dyes, bromophenol blue was applied by Shirokova and Charykov [222] for the determination of erythromycin. It has been established by Regosz et al. [223] that a pH 4.2 medium is optimal for the use of bromophenol blue and the absorbance at 415 nm is suitable for the assay of erythromycin content of pharmaceutical preparations. By applying bromothymol blue, an analytical method was elaborated by Slavin et al. [224] for the estimation of oleandomycin.
Protective effect of the solvent extracts of Portulacca oleracea against acidified ethanol induced gastric ulcer in rabbits
Published in Drug and Chemical Toxicology, 2022
Muhammad Shah Zeb Jan, Waqar Ahmad, Atif Kamil, Mir Azam Khan, Maqsood Ur Rehman, Irfan ullah, Muhammad Saeed Jan
The gastric content obtained from dissected stomach was centrifuged at 2500 rpm for 10 min to remove solid material. The pH of the supernatant of gastric juice was measured with help of pH meter. For the measurement of free acidity of gastric juice, 2–3 drops of methyl orange reagent was added to the gastric juice and titrated with 0.01 N NaOH till the appearance of pale color. The volume of added NaOH was noted. Then, 2–3 drops of phenolphthalein were added to the same solution for measurement of total acidity. The titration was carried out until pink color appeared. The total volume of NaOH added to the solution was noted. Acidity was measured with the help of the following formula (Katary and Salahuddin 2017).
Diallyl disulphide-loaded spherical gold nanoparticles and acorn-like silver nanoparticles synthesised using onion extract: catalytic activity and cytotoxicity
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2020
You Jeong Lee, Song-Hyun Cha, Hyunjo Kim, Sung Eun Choi, Seonho Cho, Youmie Park
Potassium gold(III) chloride, 4-nitrophenol, silver nitrate, sodium hydroxide, poly(ethylene glycol) methyl ether thiol (MW 2 kDa), diallyl disulphide (≥98%) and sodium borohydride were purchased from Sigma-Aldrich (St. Louis, MO, USA). Methyl orange was purchased from Fluka (AG, Buchs, Switzerland). Foetal bovine serum (FBS) was obtained from GE Healthcare HyClone™ (Victoria, Australia). Penicillin-streptomycin (10,000 U/mL), trypsin-EDTA (0.25%, without phenol red) and high-glucose Dulbecco’s modified Eagle’s medium (DMEM) were obtained from Gibco (Thermo Fisher Scientific, MA, USA).
Effects of coating layer and release medium on release profile from coated capsules with Eudragit FS 30D: an in vitro and in vivo study
Published in Drug Development and Industrial Pharmacy, 2018
Eskandar Moghimipour, Mohsen Rezaei, Maryam Kouchak, Jafar Fatahiasl, Kambiz Ahmadi Angali, Zahra Ramezani, Mohsen Amini, Farid Abedin Dorkoosh, Somayeh Handali
Eudragit® FS 30D and theophylline were kindly donated by RÖhm GmbH (Darmstadt, Germany) and Dr. ABIDI Pharmaceutical Co., Tehran, Iran, respectively. Glyceryl monostearate (GMS) and triethyl citrate (TEC) were obtained from Sigma (Germany). Tween 80 and methyl orange were acquired from Merck (Germany). Size 9 capsules were purchased from Capsugel (Belgium). Barium sulfate (BaSO4) was obtained by Darou Paksh Pharmaceutical Mfg. Co., Tehran, Iran. Gastrografin was purchased from BerliMed S.A. (Spain), and male Wistar rats were provided from the Pasteur Institute of Iran.