China
Africa
Explore chapters and articles related to this topic
Pharmacodynamics of Anticoagulants
Published in Hartmut Derendorf, Günther Hochhaus, Handbook of Pharmacokinetic/Pharmacodynamic Correlation, 2019
Dennis Mungall, Richard H. White
Numerous authors have proposed equations to predict the steady-state dose of warfarin based a patient’s initial response.102–106 These equations, which were generated before widespread use of the INR, predict a dose to reach a specific prothrombin ratio (e.g., PR = 1.5 to 2.5). This approach allows only the prediction of the maintenance dose. Most of the equations are based on the PT response the morning after the third dose of 10 mg of warfarin per day. These models are not very accurate, and no prospective trials have been performed comparing the use of one of these equations to trial and error dosing by physicians to determine if this approach affects any outcome. Until such studies are performed, use of any of these empirical formulas must be considered experimental. The equations are summarized in Table 5.
Procedures for Calculating Empirical and Molecular Formulas
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
The simplest formula (or empirical formula) is the simplest whole number ratio of elements in a compound. This type of formula is the only formula commonly used for ionic compounds or for those compounds that come as a large three-dimensional (3-D) array.
Biosynthetic Pathway of Artemisinin
Published in Tariq Aftab, M. Naeem, M. Masroor, A. Khan, Artemisia annua, 2017
Artemisinin is an endoperoxide sesquiterpene lactone that is produced by aerial parts of Artemisia annua L. and is effective against multidrug‑resistant strains of the malarial parasite. The isolation and characterization of artemisinin from A. annua is considered one of the most novel discoveries in recent medicinal plant research. It was isolated from the plant in 1972 (Roth and Acton, 1989) and its structure was determined in 1979 by x-ray analysis (Brown, 1993). It has an empirical formula of C (carbon), H (hydrogen), and O (oxygen). Artemisinin has a peroxide bridge to which its antimalarial properties are attributed. It has a unique structure and lacks a nitrogen-containing heterocyclic ring, which is found in most antimalarial compounds, as explained in Figure 6.1. Artemisinin is an odorless, colorless compound that forms crystals with a melting point of 156° C– 157° C. The molecular weight as determined by high-resolution mass spectroscopy is m/e 282.1742 m+ (Figure 6.1) (Brown, 1993).
Formulation, characterization, optimization, and in-vivo performance of febuxostat self-nano-emulsifying system loaded sublingual films
Published in Drug Delivery, 2021
Basant A. Habib, Amina S. Abd El-Samiae, Boushra M. El-Houssieny, Randa Tag
Febuxostat (FXS) is a potent, non-purine, selective xanthine oxidase inhibitor. Xanthine oxidase is needed to sequentially oxidize both hypoxanthine and xanthine (purines) to uric acid. Thereby the production of uric acid by the body through the metabolization of purines is reduced by FXS, thus it is used in the treatment of gout, chronic hyperuricemia and major complications of chronic kidney disease (Younes et al., 2016). FXS was found to be preferable than allopurinol in reducing the serum uric acid levels (Alhakamy et al., 2020). Its empirical formula is C16H16N2O3S with a molecular weight of 316.37. It is a weak acid (pKa = 3.42), insoluble in water (aqueous solubility is 12.9 μg/ml) and considered to be a BCS class II compound (Yin et al., 2018). Its oral bioavailability is moderate (<49%) due to its low aqueous solubility and its exposure to enzymatic degradation in both intestine and liver. Moreover, the presence of food decreases the maximum concentration of FXS in plasma after oral dosing (Cmax) by 38–49% (Yin et al., 2018; Alhakamy et al., 2020). Yet, the marketed dosage forms of FXS are confined only to oral tablets of different doses (40, 80, and 120 mg) (Gaffo & Saag, 2009). Trials have been made to formulate other dosage forms of FXS; such as: transdermal ethosomes (El-Shenawy et al., 2020), self-nano-emulsified loaded transdermal films (Alhakamy et al., 2020), and sublingual tablets (Bhide et al., 2019).
Terminalia ferdinandiana Exell. Fruit and Leaf Extracts Inhibit Proliferation and Induce Apoptosis in Selected Human Cancer Cell Lines
Published in Nutrition and Cancer, 2018
Chromatographic separations were performed as previously described (21). Briefly, 2 µl of sample was injected onto an Agilent 1290 HPLC system fitted with a Zorbax Eclipse plus C18 column (2.1 × 100 mm, 1.8 µm particle size). The mobile phases consisted of (A) ultrapure water and (B) 95:5 acetonitrile/water at a flow rate of 0.7 ml/min. Both mobile phases were modified with 0.1% (v/v) glacial acetic acid for mass spectrometry analysis in positive mode and with 5 mM ammonium acetate for analysis in negative mode. The chromatographic conditions utilized for the study consisted of a 5 min isocratic phase at 5% B, a gradient of (B) from 5% to 100% was applied from 5 to 30 min, followed by a 3 min isocratic phase at 100% B. Mass spectrometry analysis was performed on an Agilent 6530 quadrapole time-of-flight spectrometer fitted with a Jetstream electrospray ionization source in both positive and negative mode. Data were analyzed using the Masshunter Qualitative analysis software package (Agilent Technologies). Each extract was analyzed using the Find by Molecular Feature function to generate a putative list of compounds which was then screened against two accurate mass databases: a database of plant compounds of therapeutic importance generated specifically for this study (800 compounds); and the Metlin metabolomics database (24,768 compounds). Empirical formula for unidentified compounds was determined using the Find Formula function in the software package.
Bictegravir in a fixed-dose tablet with emtricitabine and tenofovir alafenamide for the treatment of HIV infection: pharmacology and clinical implications
Published in Expert Opinion on Pharmacotherapy, 2019
Hanh Thi Pham, Thibault Mesplède
The BIKTARVY® tablet is composed of BIC 50 mg, with two active anti-HIV drugs: FTC (200 mg) and TAF (25 mg). The tablet is oval, purplish-brown, and 15 mm in length. A summary of the tablet components is in Box 1. The chemical name for BIC (GS-9883) is (2R,5S,13aR)-8-hydroxy-7,9-dioxo-N-(2,4,6-trifluorobenzyl)-2,3,4,5,7,9,13,13a-octahydro-2,5-meth-anopyrido[1ʹ,2ʹ:4,5]pyrazino[2,1-b][1,3]oxazepine-10-carboxa-mide. The empirical formula is C21H18F3N3O5 with a molecular weight of 449.386 g/mol. Bictegravir sodium itself (C21H17F3N3NaO5) is an off-white to yellow powder with a water solubility of 0.1 mg/mL at 20°C [46].