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Biopharmaceutics Aspects of Dermally Applied Drug Delivery Systems
Published in Tapash K. Ghosh, Dermal Drug Delivery, 2020
In the absence of quantifiable systemic level, traditional IVIVC from topical dosage forms for local therapy is not feasible. For TDS (be it matrix, reservoir or semisolid type), establishment of an IVIVC may be possible. Transdermal dosage forms are designed for extended release; however, the drug release and permeability mechanism from these systems are more complicated than oral extended release dosage forms. Transdermal IVIVC generally uses drug permeability data whereas oral drug IVIVC uses dissolution data. In order to obtain in vitro permeability data, excised human skin or animal skin are used to conduct an in vitro test using a diffusion cell. Some studies used artificial membrane to conduct permeability tests. A few studies employed USP apparatus, including the use of Apparatus 5 (Paddle over Disk Method), Apparatus 6 (Rotating Cylinder Method) and Apparatus 7 (Reciprocating Holder Method) as described in USP General Chapter <724> describing Drug Release for transdermal systems (TDS) and other dosage forms to obtain drug release data from TDS [5]. However, drug release data might not be appropriate to be used to simulate the process of in vivo drug penetration through the skin.
Performance Testing
Published in Marc B. Brown, Adrian C. Williams, The Art and Science of Dermal Formulation Development, 2019
Marc B. Brown, Adrian C. Williams
Experimental duration should consider several factors. Firstly, membrane integrity must be maintained throughout the experimental period. This will vary with the membrane being employed – clearly artificial membranes are generally more robust than are biological tissues. Secondly, if assessing pseudo steady-state flux of a permeant, it is often advised that the experiment run for a time period greater than 2.7 times the lag time – steady-state conditions are not attained until this period. Thirdly, the experimental duration may depend on the permeant assay sensitivity; poor permeants with difficult assays need to run long enough to allow permeation of sufficient material for detection and analysis.
Fungal Sterols
Published in Rajendra Prasad, Mahmoud A. Ghannoum, Lipids of Pathogenic Fungi, 2017
Because free sterols are principally membrane components, it is interesting to look at the interrelations between sterols and phospholipids. The physical effects of sterols in artificial membranes have been discussed earlier. We have compared the properties of yeast membranes that had altered sterol composition either through mutant sterol accumulation or by feeding sterols to sterol auxotrophs. As a probe, the fluorescence anisotropic behavior of 1,6-diphenyl-1,3,5-hexatriene was monitored in different membrane preparations. We have observed that when auxotrophs were fed with different sterols, there was a substantial accommodation by the cells51 of different sterols and plasma membranes were isolated from these cells. Each of these preparations showed no discontinuity in the plots of the steady-state fluorescence anisotropy of the probe. Liposomes were prepared from the phospholipids that were produced by the auxotroph. The specific sterol that had been fed to the yeast showed patterns of anisotropy that were similar to that of membrane preparations, having no discontinuities. A contrasting result was obtained when liposomes were prepared from phospholipids extracted from a culture but were mixed with a sterol which was different from the one that was used to grow the culture. Discontinuities were found. This was true of each of the sterols tested, when they were mixed with phospholipids prepared from cells grown on a different sterol.
Metoclopramide nasal spray in vitro evaluation and in vivo pharmacokinetic studies in dogs
Published in Pharmaceutical Development and Technology, 2018
Ying Li, Xianpeng Fan, Wanqing Li, Peng Yang, Hui Zhang, Daoquan Tang, Xiaoxin Yin, Jianxu Sun, Aiping Zheng
Commonly, Franz diffusion chamber is a typical ex vivo drug permeation model. The artificial membrane (Soliman et al. 2010), rabbit (Colombo et al. 2011), sheep (Mahajan & Gattani 2010), bovine (Ventura et al. 2006) or porcine (Ekelund et al. 2005) nasal epithelium mucosa were used to this Franz diffusion model. Among them, due to lack the expression of active transport and enzyme, artificial membrane is not an optimal model. Rodents, such as rabbits or rats, have a sensitive smell, so nasal epithelium mucosa area is relatively large. Moreover, some active transporters have been demonstrated in rabbit nasal mucosa (Cremaschi et al. 1998). Therefore, rabbit nasal mucosa was applied to in vitro permeation study. Permeation experiment data indicated that the drug has good permeability. Permeation enhancers decreased the permeability of MCP, while preservative could enhance drug absorption modestly.
Development of lipid nanoparticles for transdermal loteprednol etabonate delivery
Published in Journal of Microencapsulation, 2022
Burcu Üner, Samet Özdemir, Çetin Taş, Yıldız Özsoy, Melike Üner
The determination of in vitro release profiles of formulations was achieved by using Franz diffusion cells (Permegear, USA). The diffusion area of the Franz diffusion cell was 2.88 cm2 and the receptor volume was 20 mL. The release study was conducted under the sink conditions (Ghadiri et al.2012). 2 mL of formulations were put into a donor chamber separated with an artificial membrane (Spectra/Por® Dialysis membrane, USA, with Mw cut-off at 3.5 kDa) from the receiver chamber. At specified periods, 1 mL samples were taken from the release medium (PBS) and then replenished by volume equivalent to fresh medium (Ng et al.2010). HPLC method was applied for the quantification of samples.
How can we better realize the potential of immobilized artificial membrane chromatography in drug discovery and development?
Published in Expert Opinion on Drug Discovery, 2020
Biological membranes are essential for drug efficacy, triggering research in the field of artificial membrane technology in the aim to face impediments in the early drug discovery phase. The development of IAM chromatography, by immobilizing crucial phospholipids on silica support, has been a key advancement toward this direction, providing an intermediate step between in silico and more complex in vitro assays. Initially, IAM Chromatography was intended to meet the criticism toward the octanol-water system and to provide an alternative to traditional lipophilicity. However, understanding of the molecular factors, involved in IAM retention, which define it as a border case between passive diffusion and binding, highlights many other applications. Thus, one measurement on an IAM column provides information for more issues relevant to multi-objective drug discovery, while it offers the possibility to determine more than one index, allowing the medicinal chemist to choose the most appropriate for his/her purpose. Isocratic retention factors logkw, their gradient elution alternative CHI, as well as their discrete polar component Δlogkw have been so far successfully used to model ADME properties, in particular permeability through essential biological barriers, such as human intestinal and blood–brain barrier. The binding component in IAM retention permits rapid estimation of complex pharmacokinetic properties that involve nonspecific binding, while increased IAM retention may be an indication for phospholipidosis [20], extending its use to drug safety. Moreover, IAM retention may be associated with drug intracellular concentration, cell accumulation, or retention [17].