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Organic Nanocarriers for Brain Drug Delivery
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
Marlene Lúcio, Carla M. Lopes, Eduarda Fernandes, Hugo Gonẹalves, Maria Elisabete C. D. Real Oliveira
Many therapeutic agents are not effective to treat CNS diseases because of their low lipid solubility for BBB penetration. Docetaxel (DTX), an inhibitor of microtubule depolymerisation, has been used for the treatment of many malignancies, including brain cancer [213]. DTX presents restricted clinical use which is explained by its poor aqueous solubility and nonspecific in vivo distribution, resulting in toxic effects [214, 215]. To overcome these limitations, Gaoe et al. [206] proposed the use of nanoemulsions to encapsulate DTX. The authors prepared nanoemulsions by the high-energy homogenisation method using soybean oil and egg lecithin and poloxamer 188 as surfactant agents. The mean droplet size of the nanoemulsion was 72.3 nm with a PDI of 0.19, the average zeta potential was -6.38 mV and the EE was 93.1%. In vitro toxicity tests demonstrated that the nanoemulsion had comparable antiproliferative effects in both U87MG cells and bEnd.3 cells. In vivo toxicity studies in healthy mice resulted in a slight change in the liver cells for the DTX-loaded nanoemulsion-treated group, whereas the administration of Taxotere® (commercial formulation) induced hydropic degeneration of liver cells. The main adjuvant used in Taxotere® is PS-80 which is associated with adverse effects such as peripheral neuropathy and acute hypersensitivity reaction [216]. In addition, nanoemulsions, i.v.-administered in mice, have been distributed to the brain, have accumulated at the glioma site and have been effective at targeting glioma sites and extending the median survival time of glioma mice.
Electronic Properties of Natural and Modeled Bilayer Membranes
Published in Andrew A. Marino, Modern Bioelectricity, 2020
Dyes embedded in BLMs or present in the bathing solution have been shown to determine the occurrence and the value of the photoelectric response. A biphasic photovoltage was seen in a system composed of egg lecithin, and bathed with cyanine dye from one side (91). The action spectrum was similar to the absorption spectrum of the dye, and the photovoltage was proportional to the light intensity until a saturation value was reached. A similar dependence of the pho tovol tage upon the dye concentration was found, however after exceeding a certain concentration the photovoltage decreased. An extensive study of the photoelectric responses of similar systems containing various cyanine dyes was carried out (92). Mechanisms involving intermolecular electron transfer in the photoresponse generation were assessed as unlikely for most of the cases. Instead, intermolecular charge shifts and translocations of dyes in membranes were suggested.
Nanoemulsions in Non-Invasive Drug Delivery Systems
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Ratna Jyoti Das, Subhabrata Ray, Paulami Pal, Anup Kumar Das, Bhaskar Mazumder
Different formulations of nanoemulsions have been developed to enhance the oral bioavailability of drugs with solubility problems (like paclitaxel). In a recent study, o/w nanoemulsions were prepared with pine nut oil as the internal phase and egg lecithin as the primary emulsifier. The stearyl amine gives a positive charge while deoxycholic acid gives a negative charge to the droplets. The particle size ranged from 100–120 nm, with zeta potential varying between 34–245 mV. Oral administration of the nanoemulsions significantly increased the concentration of paclitaxel in the systemic circulation system compared to the aqueous control. The study indicated that it can be a promising vehicle to increase the oral bioavailability of hydrophobic drugs (Charles and Attama, 2011; Rutvij et al., 2011; Subhashis et al., 2011; Yashpal et al., 2013; Zhang et al., 2014).
Progress in spray-drying of protein pharmaceuticals: Literature analysis of trends in formulation and process attributes
Published in Drying Technology, 2021
Joana T. Pinto, Eva Faulhammer, Johanna Dieplinger, Michael Dekner, Christian Makert, Marco Nieder, Amrit Paudel
With respect to lipid excipients, dipalmitoyl phosphatidylcholine (DPPC), an endogenous phospholipid to the lung, has been frequently applied to protein formulations, particularly, inhaled ones. In combination with sugars (i.e. lactose, mannitol, trehalose), DPPC has been used to produce spray-dried inhalable particles of bFGF, human growth and parathyroid hormones, wherein the lipid showed to induce aggregation of bFGF.[94] For human growth and parathyroid hormones, DPPC was shown to enrich the surface of the spray-dried particles, thus stabilizing them. The lipid acted as barrier to moisture uptake, thereby preventing the crystallization of the sugar present in the formulations of the hormones.[84,86] In combination with Eudragit® E100, DPPC was used to produce microparticles of albumin that exhibited sustained release profiles.[169] Another lipid, egg lecithin (Lipoid E80®), was used in combination with hyaluronic acid to produce sustained release formulations of human growth hormone for subcutaneous injection.[82] Triethyl acetate, a lyophilic molecule, was applied as a plasticizer for the enteric coating of oral vaccines of Vibrio cholera.[121]