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Biological monitoring of chemical exposure
Published in Sue Reed, Dino Pisaniello, Geza Benke, Principles of Occupational Health & Hygiene, 2020
Gregory E. O’Donnell, Martin Mazereeuw
The elimination half-life is important when estimating the internal dose, and is relevant to determining when the most appropriate time is to take a biological monitoring sample. Generally speaking, most polar compounds (parent compounds or metabolites) are excreted fairly quickly within hours and certainly less than one day. These compounds are best sampled at the end of the shift or the following morning. These compounds include most solvents, organophosphate insecticides, herbicides, isocyanates, 4,4’-methylene-bis-chloroaniline, fluoride, methyl bromide, cyanide and cytotoxic drugs. Compounds with elimination half-lives greater than one day accumulate over the working week and hence are best sampled at the end of the last shift of the work week. These compounds include most metals, chlorinated solvents such as trichloroethylene and perchloroethylene, and polycyclic aromatic hydrocarbons. Compounds with longer elimination half-lives include some heavy metals such as mercury, cobalt, cadmium, lead and manganese, and endocrine disruptor chemicals such as polychlorinated biphenyls and organochlorine insecticides. These chemicals are absorbed into body organs and lipophilic tissue; they are slowly released into the blood and reach a steady-state concentration that allows sampling at any time.
A meticulous overview on drying-based (spray-, freeze-, and spray-freeze) particle engineering approaches for pharmaceutical technologies
Published in Drying Technology, 2021
Sagar Pardeshi, Mahesh More, Pritam Patil, Chandrakantsing Pardeshi, Prashant Deshmukh, Arun Mujumdar, Jitendra Naik
They are designed to achieve a prolonged therapeutic effect by continuously releasing medication at a nearly constant rate. The rate-controlling step in CR dosage form is the release of the drug from the dosage form and the absorption of the drug will be in a controlled manner. The dosing frequency could be reduced by giving a single dose of CR dosage form which provides constant blood level for a period of time as designed thereby eliminate fluctuation in the plasma drug concentration which ultimately reduces side effects and results in improved patient compliance.[149] The drawbacks include dose dumping, patient variability, high cost, and poor in vitro–in vivo correlation. The drugs with a narrow therapeutic index, poor absorption, large dose, short or long elimination half-life, low aqueous solubility, and possess extensive first-pass metabolism are not the ideal candidate for CR formulation. The parameters that should be considered while selecting a drug candidate for CR include; biological elimination half-life should be in between 2 and 6 h. The molecular weight reflects the diffusivity, and thus, for spherical molecules it should be below 150 Daltons and for chain-like molecules, it should be below 400 Daltons. The intrinsic absorption rate should be greater than the release rate whereas solubility should be 0.1–1.0% in non-ionized form. In addition, absolute bioavailability should be 75% or more with a broader therapeutic index and lower protein binding.[144,150]
Flurbiprofen-loaded interpenetrating polymer network beads based on alginate, polyvinyl alcohol and methylcellulose: design, characterization and in-vitro evaluation
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Non-steroidal anti-inflammatory drugs are frequently preferred for the treatment chronic disorders caused by inflammation [1]. Flurbiprofen (FBP), a phenyl propionic acid derivative non-steroidal anti-inflammatory drug, is is used commonly worldwide for long-term treatment of musculoskeletal and joint disorders such as rheumatoid arthritis and osteo arthritis [2–4]. However, FBP, a poor water soluble drug, requires frequent dose administration in order to achieve therapeutic concentration because of its short elimination half-life (2–6 h) [2,5]. In addition, like other non-steroidal anti-inflammatory drugs, when this drug is taken orally it shows adverse side effects including gastrointestinal disorders [6–8], and is rapidly completely absorbed following oral administration [4]. Therefore, gastrointestinal problems and other side effects can be reduced by using biodegradable beads/micro-nano spheres of this drug. The related studies concerning the the encapsulation of FBP have been reported in the literature [3,6,8–10]. Coimbra et al. [6] prepared poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microspheres containing flurbiprofen by an oil-in-water emulsion solvent evaporation method as a particulate drug delivery system for localized administration. Kawadkar et al. [8] also investigated the drug release behavior of FBP-loaded genipin crosslinked gelatin microspheres. On the other hand, Lu et al. [9] prepared gelatin microspheres including flurbiprofen using a emulsion-congealing method for intra-articular administration.
Production of aceclofenac-loaded sustained release micro/nanoparticles using pressure homogenization and spray drying
Published in Drying Technology, 2018
Rameshwar Deshmukh, Arun Mujumdar, Jitendra Naik
Aceclofenac is a NSAID. It is used for the relief from pain and inflammation. A major disadvantage of NSAID therapy is potential negative reactions such as gastrointestinal effects including bleeding, and ulceration or perforation of the intestinal wall. The mean plasma elimination half-life of aceclofenac is around 4 h and therefore, it is considered as an ideal candidate for the sustained drug delivery system to achieve improved therapeutic efficacy.[19202122] The frequent dosing, that is, required with NSAIDs often leads to patient noncompliance. To reduce the dosing frequency and adverse side effects, prolonged release formulation of aceclofenac is essential. Hence, aceclofenac-loaded micro/nanoparticles are being considered to overcome the side effect and to improve patient compliance.[19]