China
Africa
Explore chapters and articles related to this topic
Membrane Systems
Published in Agis F. Kydonieus, Controlled Release Technologies: Methods, Theory, and Applications, 2019
Typical of recent clinical trials, one study84 described implantation of six capsules (3.5 mm long and 2.4 mm OD) in each subject’s left forearm, with an 11-gauge trocar needle and a local anesthetic. Each capsule contained 35 mg of megestrol acetate and released approximately 50 µg/day. The plasma levels of megestrol acetate varied between subjects and from day to day for a given subject, but stabilized after about 3 months at about 0.6 ng/mℓ plasma. At this rate of administration, which prior studies suggest may be three times that required to prevent conception, the normal ovarian hormone patterns were disturbed, and ovulation was inhibited. Absorption from the implanted PDMS capsules in vivo has been reported by a number of observers to vary significantly. The in vivo measurements reported in such studies employ radioimmunoassay, which makes possible safer and more convenient determination of the functionality of delivery systems in vivo than was feasible, even with radioactively labeled drug, during the earlier days of controlled-release development.215
Thin-Layer Chromatography in Pharmaceutical Analysis
Published in Bernard Fried, Joseph Sherma, Practical Thin-Layer Chromatography, 2017
Elena Dreassi, Giuseppe Ceramelli, Piero Corti
Smets el al43 describe a very quick method consisting of methanolic extraction with a Stomacher apparatus and HPTLC analysis on silica gel layers, C18 and CN, developed with seven different mobile phases for the qualitative and quantitative determination of different compounds with anabolic properties and their esters in injection sites in animal tissues. The plates were dipped into a 5% ethanolic solution of sulfuric acid and then heated; the spots were identified in fluorescence at 366 nm; Rf values and colors obtained were compared with those of standard compounds. In comparison with techniques currently used, as immunoassay, this method has the advantage of allowing the separation and identification of the esterificated forms of the anabolics as estrogens (stilbenes and their esters, estradiol and its esters, ethinylestradiol, and mestranol), androgens (methyltestosterone, testosterone and its esters, nortestosterone and esters, trembolone and trembolone acetate, stanozolol, boldenone, methyIboldenone, and chlortestosterone) or gestagens (progesterone, medroxyprogesterone acetate, chlormadinone acetate, melengestrol acetate, and megestrol acetate). After a first monodimensional screening, the extract has to be concentrated if no characteristic spots of the different compounds can be observed. In the case of different esters within the same compound, a second elution (bidimensional) with various mobile phases has to be carried out. In case there are still doubts about the attribution of the spots, it is recommended to adopt plates of a different type other than CN or C18.
Nanotechnology in Drug Delivery
Published in Yubing Xie, The Nanobiotechnology Handbook, 2012
Jungmin Cho, Sungwon Kim, Kinam Park
One of the main physicochemical properties of a drug for successful development into clinical application is the water solubility. In many cases, the drug solubility in water is not high enough to lead to in vivo therapeutic efficacy. Many promising drugs have been abandoned due to their poor water solubility. More than half of all the newly developed drugs are known to have poor water solubility. Poor water solubility requires use of higher amount of the drug, and this in turn may result in higher incidents of side effects (Speiser 1998). For this reason, poorly soluble drugs have been formulated by a variety of different approaches, ranging from simple salt formation to complicated drug delivery systems such as polymer micelles. Of these, the nanocrystal approach has received significant attention. Drug nanocrystals dissolve faster than their microsized drug counterparts due to substantially increased surface area (Junghanns and Müller 2008). Several nanocrystal formulations have become clinically available. Sirolimus, an immunosuppressant, is a poorly water-soluble drug, and it was available as an oral solution and tablet (Rapamune®, Pfizer). When it was made into a formulation of nanocrystals less than 200 nm (Rapamune), the solid oral formulation was equally effective as the solution formulation (Merisko-Liversidge et al. 1996). Rapamune is a product generated by NanoCrystal® technology from Elan Pharmaceuticals. Another three examples of the NanoCrystal technology are Megace ES® (megestrol acetate, Par Pharm Co.), Tricor® (fenofibrate, Abbott), and Emend® (aprepitant, Merk) (Adis 2007; Deschamps et al. 2009).
Occurrence and fate of pharmaceuticals in effluent and sludge from a wastewater treatment plant in Brazil
Published in Environmental Technology, 2021
Ramiro Pereira Bisognin, Delmira Beatriz Wolff, Elvis Carissimi, Osmar Damian Prestes, Renato Zanella
Pharmaceuticals of human and veterinary prescription, and hormones were the assessed analytes, among them one finds β-estradiol; paracetamol; megestrol acetate; androstenedione; caffeine; ciprofloxacin; clindamycin; chloramphenicol; chlortetracycline; danofloxacin; diclofenac; doxycycline; enrofloxacin; estriol; estrone; ethisterone; fenbendazole; fenbendazole sulfone; florfenicol; flunixin; ivermectin; lincomycin; marbofloxacin; metronidazole; norfloxacin; ofloxacin; oxytetracycline; progesterone; sarafloxacin; sulfacloropyridazine; sulfadiazine; sulfadimethoxine; sulfadoxine; sulfamazine; sulfamethoxazole; sulfaquinoxalin; sulfathiazole; testosterone; tetracycline; tilmicosin; tylosin and trimethoprim. Solid analyte standards (purity ranging from 95.0 to 99.6%) were purchased from Dr. Ehrenstorfer (Germany) and Witega (Germany). The standard solution of each analyte was prepared at a concentration of 1,000 mg L−1 in acetonitrile. Afterwards, a solution encompassing a mixture of all compounds (each with 10 mg L−1) was prepared at acetonitrile. These solutions were stored in amber bottles at ± 5°C.