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Cyclodextrins and Skin Disorders: Therapeutic and Cosmetic Applications
Published in Andreia Ascenso, Sandra Simões, Helena Ribeiro, Carrier-Mediated Dermal Delivery, 2017
Oluwatomide Adeoye, Ana Figueiredo, Helena Cabral Marques
The biosynthesis of CyD is facilitated by an enzymatic product of bacteria known as cyclodextrin glucosyltransferase enzyme (CGtase). The CGtase enzyme can be produced from different types of microorganisms such as strains of Bacillus sp. (B. amylobacter, B. macerans, B. circulans, B. subtilis, B. megaterium, alkalophilic Bacillus sp.), Klebsiella (K. pneumoniae, K. oxytoca), Thermoanaerobacter sp., Clostridium sp. [16]. During the biosynthesis of CyD, CGtase induces the intramolecular transglycosylation reaction to degrade the amylose helix fraction of starch, and facilitate the subsequent cyclization of the product to form toroidal or doughnut shaped molecules (Fig. 13.2). This toroidal shape is due to the stabilization of the C2-C3 hydroxyl groups by hydrogen bonds, and its rigid non-rotating structure. The most important characteristic of the CyD toroids is the hydrophilic exterior surfaces and hydrophobic interior cavities, which confers the ability to clathrate various molecules, thus forming inclusion complexes. This toroidal characteristic is due to the orientation of the hydroxyl groups of the glucose residues towards the external surfaces of the toroid with the primary (C-6) and secondary (C-2 and C-3) hydroxyl groups at the narrow and wider edges, respectively. On the other hand, the interior cavity is lined by skeletal carbons and ethereal oxygens, which give it a lipophilic character [15,18–21]. Many types of starch have been used as substrates for CyDs biosynthesis. However, potato starch is still the most commonly used due to high yield [22].
Critical Issues in the Evaluation of Histochemical and Biochemical Methods for Steroid Receptor Analysis *
Published in P. Pertschuk Louis, Lee Sin Hang, Localization of Putative Steroid Receptors, 2018
Kenneth S. McCarty, Jr David L. Ingram, Kenneth S. McCarty Sr.
Several investigators have used immunocytochemical methods with antibody directed against the sex steroid in attempts to localize ER on frozen sections or in fresh tumor cells.24,36,37,86,88,89,91,93,100-107 Tissues are initially incubated with estradiol or estrogen derivatives, followed by washing and incubation with antiestradiol antibodies. Either this antibody or a second antibody “tagged” with a fluorescein- or peroxidase-linked secondary antibody is used for visualization. The use of frozen sections brings into play previous criticisms concerning diffusion and/or extraction of estrogen receptor in aqueous media, although several studies have used fixed tissues. The question of the availability of receptor-bound estradiol to antiestradiol antibodies must also be raised. Evidence suggests the reaction between estrogen receptor and estradiol is clathrate; that is, the estradiol is “enveloped” by receptor in a process which involves a conformational change of receptor. Several investigations, including a convincing study by Morrow et al.,108 indicate that this altered estradiol-receptor complex is not capable of reacting with antiestradiol antibodies in vivo or in vitro.109,110 Attempts to maximize the antigenic surface of the steroid by use of polymerized polyestradiol phosphate (PEP) by Pertschuk have been met with much criticism and have been discontinued.105,110-112 It seems likely that steroid bound to nonspecific type II or type III receptors is more accessible to antibody than is estradiol bound to ER. It follows that any staining procedure utilizing antiestradiol antibodies would be more likely to detect nonspecific binding than ER-bound estradiol.
Evaluation of a docetaxel-cisplatin-fluorouracil-Au complex in human oral carcinoma cell line
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
Wannisa Khamaikawin, Kitsakorn Locharoenrat
FTIR spectroscopy was employed to investigate possible chemical structure and chemical interactions between the test drug and citrate-capped Au nanoparticles (Figure 1). Docetaxel presented characteristic peaks of the benzene ring at 711 cm−1 and 1494 cm−1, a peak at 1713 cm−1 for the carbonyl group (C=O), and a peak at 3409.02 cm−1 for the primary amine group (N–H) [26]. Cisplatin presented the NH/OH stretching bands at 1296−1 and 3300 cm−1 [27,28]. 5-Fluorouracil showed peaks for the primary amine groups (N–H) at 3409.02 cm−1 and 3566.89 cm−1 as well as one for the carbonyl group (C═O) at 1647.80 cm−1 [29]. Citrate-capped Au nanoparticles presented a characteristic peak at 1396 cm−1, conforming to the symmetric and asymmetric stretching of (COO−) [28,30]. Some characteristic peaks of plain docetaxel, cisplatin, and 5-fluorouracil still existed in the docetaxel-cisplatin-fluorouracil combination. These data suggested a chemical interaction or band overlap (no new peak shown). The docetaxel-cisplatin-fluorouracil-Au complex exhibited shifts in all spectra, indicative of the substitution and the success of interactions between the test drug and the Au colloidal dispersion. The characteristic peaks of docetaxel reduced in the complex, which proved that docetaxel entered the cavity of the clathrate-like water.
[6]-Shogaol/β-CDs inclusion complex: preparation, characterisation, in vivo pharmacokinetics, and in situ intestinal perfusion study
Published in Journal of Microencapsulation, 2019
Ran Li, Rui Bao, Qiu-Xuan Yang, Qi-Long Wang, Michael Adu-Frimpong, Qiu-Yu Wei, Toreniyazov Elmurat, Hao Ji, Jiang-Nan Yu, Xi-Ming Xu
The inclusion complex of [6]-shogaol and β-CD was prepared using saturated aqueous solution method, also known as co-precipitation method as described previously with slight modifications (Zhang et al.2015). Briefly, β-CDs and [6]-shogaol were accurately weighed based on the molar ratio (1:1) of the active drug to excipient based on earlier reports (Lili et al.2014, Pinho et al.2015, Savic et al.2015, Zhang et al.2015, Al-Nasiri et al.2017, Li et al.2017). The [6]-shogaol was dissolved in an appropriate amount of methanol, and was added to the β-CD saturated aqueous solution using a syringe, and stirred magnetically at a constant temperature of 55 °C for 3 h. It was stirred continuously at 37 °C for 2 h, and then stirred at 25 °C for 1 h, before being placed in a freezer at 4 °C for 24 h. The clathrate was washed with a small amount of double distilled water (DDW) and petroleum ether. Finally, the 6-S-β-CDs were dried with vacuum drier to obtain a white powdery clathrate, which was weighed and the yield of the clathrate was calculated.
Gavage approach to oxygen supplementation with oxygen therapeutic Ox66™ in a hypoventilation rodent model of respiratory distress
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
William H. Nugent, Danuel A. Carr, Rosa MacBryde, Erica D. Bruce, Bjorn K. Song
Oral versus inhalation administration changes the therapeutic kinetics. Pulmonary-based treatments to improve oxygenation (e.g. mechanical ventilation and concentrated oxygen) and extracorporeal membrane oxygenation, which functions similar to a cardiac bypass by externally reoxygenating blood [29,30], have immediate impacts on PaO2 and oxygen delivery. The gut also offers a vascularized surface similar in size to the lungs for absorption [31], which has shown promise during enteral passage of hyper-oxygenated perfluorocarbons [32]. However, two key differences are blood perfusion and a rate-controlling digestive step. The lungs have their own, dedicated half of the heart to ensure gas exchange is not diffusion limited, whereas the mesenteric blood flow accounts for about 10% of cardiac output [33]. The digestion step is specific to Ox66™, which creates a longer duration, time-release effect. Indeed, this means an immediate oxygen need to relieve critical organ hypoxia may not be feasible. But, neither would the specialized equipment, training, and personnel be required in such cases as enteral perfusion. Utilizing gavage, the response in oxygen delivery to the spinotrapezius muscle took approximately 15 min to manifest (a determinant in the sampling resolution). This was expected given gastric transit time into the small intestine and (likely) digestive kinetics of the clathrate structure. Correspondingly, effect durations were protracted compared to the immediacy of removing a gaseous oxygen supplement, which we attribute to a time-release effect. The time course of oral Ox66™ is not ideal for urgent rescue therapies but warrants further study as a complementary treatment or early intervention to reduce the cumulative hypoxic effects seen in ARDS.