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Chemical Modulation of Topical and Transdermal Permeation
Published in Marc B. Brown, Adrian C. Williams, The Art and Science of Dermal Formulation Development, 2019
Marc B. Brown, Adrian C. Williams
Permeation retarders are materials with the opposite effect to enhancers – they interact with skin components to decrease flux. Such materials could act by modification of the intracellular keratin, by altering partitioning into the tissue (i.e., by using an antisolvent), or by increasing the “rigidity” or barrier nature of the stratum corneum lipids. This last approach, to increase the order of lipid bilayers within the stratum corneum by adding further lipid like molecules, though intuitively unlikely, has shown promise. An analogue of Azone, N-0915, reduced the flux of both metronidazole and the insect repellent diethyl m-toluamide (DEET) though human epidermal membranes, whereas Azone enhanced fluxes (Hadgraft et al., 1996). These opposing properties of the two analogues probably result from their chemical structures; Azone adopts a soup spoon structure providing a larger area per molecule (illustrated in Section 3.2.2.4), whereas N-0195 is more linear and with a charge distribution that may favour electrostatic interactions with stratum corneum lipids.
Clinical applications of hyperthermia in cancer treatments
Published in Clifford L. K. Pang, Kaiman Lee, Hyperthermia in Oncology, 2015
Clifford L. K. Pang, Kaiman Lee
When HR is 130–150 beats/min, close attentions should be paid. A fugitive β-receptor retarder (e.g., esmolol) should be pumped in to the vein to keep the heart rate within 120–130 beats/min, which is more proper.
Towards a New Theory of Antioncogenesis
Published in Nate F. Cardarelli, Tin as a Vital Nutrient:, 2019
Szent-Györgyi et al.37 isolated two substances from the thymus gland, one a cell growth promoter termed “promine”, and the other a growth retarder, designated “retine”. Isolation was through methanol extraction followed by complex chromatographic separation. Both materials were evaluated against Ehrlichs sarcoma transplants in mice. Promine accelerated growth by a factor of 2 to 3× as measured by tumor weight at necropsy.37 In contrast, retine slowed tumor growth; the control tumor weights at sacrifice were 1050 ±150 mg compared to tumor weights of 225 ± 30 mg in subject mice injected with four units of retine daily. Promine enhanced growth rate, but was not carcinogenic in esse. Promine always sterilized the recipients. Later, promine was separated into two distinct fractions, one a tumor growth promoter and the other, termed “infertine”, the sterilant.38 Retine and promine were detected in other organs besides the thymus, whereas infertine appeared to be present only in the thymus.38–39 Calf thymus was used as the source. It was also noted that the older the calf, the less retine and more promine detected in the aorta.38 Chemical characterization was essentially not performed except to note that all three factors are of low molecular weight and have a nitrogen content. Interestingly, the authors note that promine makes “old” animals behave like “young” animals.38 This report ends with a discussion section, wherein it is speculated that a thymic hormone maintains in action those genes responsible for youth. Of further interest to this thesis is speculation in the subject report that the thymus may synthesize steroids, and that the atrophied thymus of patients over 70 years of age shows rejuvenation with adrenocortical or testicular failure.39
Copper release rate needed to inhibit fouling on the west coast of Sweden and control of copper release using zinc oxide
Published in Biofouling, 2018
J. Fredrik Lindgren, Erik Ytreberg, Albin Holmqvist, Magnus Dahlström, Peter Dahl, Mattias Berglin, Anna-Lisa Wrange, Mia Dahlström
An experimental generic paint was obtained from the paint manufacturer Boero Group (www.boerogroup.com). Its formulation is based on hydrogenated rosin as binder together with an acrylate as film former and erosion retarder. It is prepared by dissolving rosin in xylene to a final concentration of 50% (w w–1) using a Cowles mixer and then adding an acrylic retarder and red pigment (Fe2O3). Then the plasticizer is added followed by the extenders, barium sulfate (BaSO4) and anhydrous talc, and then the anti-sagging agent, SiO2. Finally, the viscosity of the formulation is controlled by adding once again xylene solvent. The paint is thoroughly mixed throughout this process. The dispersion of the paint components was analyzed with a grindometer.
Targeted delivery of epirubicin to breast cancer cells using poly-aptamer DNA nanocarriers prepared by the RCA method with multiple repeats of aptamers of FOXM1 and AS1411
Published in Drug Development and Industrial Pharmacy, 2023
Elham Moradi, TaranehSadat Zavvar, Mona Alibolandi, Mohammad Ramezani, Khalil Abnous, Seyed Mohammad Taghdisi
The stepwise RCA product assembly was confirmed by the agarose gel electrophoresis technique. According to Figure 1(a), the padlock probe band was behind the primer band since it had more nucleotides than the primer. The circular DNA (incubated padlock probe with primer) band was retarder than the padlock probe and primer bands, confirming their hybridization. According to Figure 1(b), the RCA product bands moved to higher molecular weight sites compared with each previous sample; since DNA nanoparticles from the RCA were obtained in various and larger sizes.
The preparation and characterisation of tasteless core-shell clarithromycin microcapsules
Published in Journal of Microencapsulation, 2022
Yu Fu, Yunjing Zhu, Xue Liang, Yihan Kong, Xiaolin Wang, Anan Zhang, Zhiqing Zhao, Jingxin Gou, Yanjiao Wang, Tian Yin, Yu Zhang, Haibing He, Xing Tang
The bitter taste is produced when the taste buds react to bitter drugs dissolved in the mouth. Due to the extreme bitterness of CAM, the addition of sweeteners and flavouring agents is not able to effectively mask it. According to the difference between the mechanism and means for taste-masking, current oral solid preparation techniques could be divided into four categories: drug properties modification, bitter retarder, flavour adding, and physical barrier (Tadros 2013).