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Narcotic Analgesics And Antagonists
Published in S.J. Mulé, Henry Brill, Chemical and Biological Aspects of Drug Dependence, 2019
Unfortunately, this conformational resemblance is based on an axially oriented phenyl group. The x-ray structure determination of dl-alphaprodine hydrochloride, a related compound, proved that the phenyl group existed in an equatorial conformation in the solid state (see Formula 20) in alphaprodine and, by analogy, in pethidine itself. However, it is now fairly well accepted that both a macromolecule which contains the receptor site, and a small drug molecule can interact and influence the conformation of the other. Whether such interaction can induce inversion through the boat form of pethidine’s piperi-dine ring to a conformation of the pethidine molecule which might satisfy the unknown morphine receptor is, again, speculation. It would be helpful if information could be obtained about the macromolecule, or macromolecular system, with which analgesics interact to produce their biological effect. At least a rational start could then be made towards the determination of actual binding sites using, perhaps, the contemporary methods of electron paramagnetic resonance spectroscopy,32 nuclear magnetic resonance spectroscopy,33,34 and fluorescent antibody techniques.35,36
Water Permeability of Amphibian Urinary Bladder
Published in Gheorghe Benga, Water Transport in Biological Membranes, 1989
Jacques Bourguet, Jacques Chevalier, Mario Parisi, Pierre Ripoche
Some other drugs reacting with carboxyl of histidyl groups of the Na+ channel, like E.D.Q.Q. (N-ethyoxycarbonyl-2-ethory-1,2-dihydroquinoline) could also be used.235 E.D.Q.Q. can activate the carboxyl group of the Na+ channel and induce the covalent binding of an exogenous nucleophile like glycine methyl ester which can be followed during the membrane purification. A nitroxide derivative of amiloride and a study of amiloride binding by electron paramagnetic resonance spectroscopy has been performed by Costa et al.236 The spin-labeled amiloride seems a useful probe for the identification of the amiloride binding site, which could be used as a molecular marker for apical membranes.
Current trends in PLGA based long-acting injectable products: The industry perspective
Published in Expert Opinion on Drug Delivery, 2022
Omkara Swami Muddineti, Abdelwahab Omri
This review provides a comprehensive overview of PLGA-based LAI as per the pharmaceutical industry perspective. Attention is needed to focus on analytical methods, physicochemical, and characterization to recognize appropriate CQAs that need to be matched during generic product development. Using advanced modeling parameters, further research should be focused on formulation and critical process parameters to set appropriate control strategies for successful scale-up, commercialization, and in vivo product performance. Hence, in vitro characterization has to be investigated thoroughly to predict in vivo performance, which helps in bioequivalence studies. To develop relevant in vitro predictive models for ISF implants, reliable technologies should be explored for understanding critical parameters such as phase separation, implant formation, degradation, drug release, etc. Different techniques such as electron paramagnetic resonance spectroscopy, ultrasound imaging techniques, UV-visible imaging, fluorescence imaging, diffusion-weighted magnetic resonance imaging, etc., helps in the understanding of the parameters mentioned.
Drug stability testing and formulation strategies
Published in Pharmaceutical Development and Technology, 2018
Guidelines for stability testing on drug substances or products are provided by the International Conference on Harmonization (ICH) as Q1A (R2) guidelines and recently World Health Organization (WHO) as TRS1010 Annex 10. The analytical methods should be reliable and ‘stability-indicating’ to demonstrate the stability of a drug substance or product under the influence of a variety of environmental factors. Whilst the use of high performance liquid chromatography is predominant for stability testing, a range of other techniques are needed for drug analysis and to understand the various mechanisms of degradation. This Special Edition of PDT features the use of electron paramagnetic resonance spectroscopy, which can provide insight into free radical formation and their effect on drug stability in pharmaceutical dosage forms.
Pharmacology, toxicity and pharmacokinetics of acetylshikonin: a review
Published in Pharmaceutical Biology, 2020
Zhiqin Zhang, Jie Bai, Yawen Zeng, Mengru Cai, Yu Yao, Huimin Wu, Longtai You, Xiaoxv Dong, Jian Ni
Acetylshikonin reduced superoxide anion generation in guinea pig polymorphonuclear leukocytes by suppressing the production of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, but it had no inhibitory effect on already generated NADPH oxidase (Kawakami et al. 1996). Weng et al. (2000) and Jiang et al. (2002) reported that acetylshikonin exerted antioxidant property in lard containing Fe3+, and showed synergistic effects with d,l-α-tocopherol. Another study proved that acetylshikonin suppressed Cu2+-induced oxidation of human low-density lipoprotein (Kim et al. 2009). Skrzypczak et al. (2015) found that acetylshikonin exhibited DPPH radical-scavenging property by using electron paramagnetic resonance spectroscopy.