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Solute Translocations
Published in Lelio G. Colombetti, Biological Transport of Radiotracers, 2020
The consequences of placing an impermeable solute on only one side of a semipermeable membrane extend beyond those described above. Water will move from the side without added solute (where the chemical activity of water is high) to the side containing the impermeable molecule (where the activity of water is low). In a completely open system, this process — called osmosis — results in dilution of the solute. In a system where the solute-containing compartment is closed, the process results in a pressure in the closed compartment. The osmotic pressure is defined practically as the pressure on the compartment containing the impermeable molecule required to prevent the flow of water. It is the semipermeable nature of biological membranes which results in the osmotic activity of cells. As the osmotic pressure depends on the concentration of the dissolved solute (and not on its chemical nature), the pressure can be maintained or modified by molecules as diverse as proteins, amino acids, and inorganic ions.
The cell
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
In other words, water moves toward an area of higher solute concentration. The solute particles may be thought of as “drawing” the water toward them. Therefore, the osmotic pressure of a solution is the pressure or force by which water is drawn into the solution through a semipermeable membrane. The magnitude of this pressure depends on the number of solute particles present. An increase in the number of particles in the solution results in an increase in the osmotic pressure and, therefore, an increase in the movement of water toward it.
Circulation of fluid between plasma, interstitium and lymph
Published in Neil Herring, David J. Paterson, Levick's Introduction to Cardiovascular Physiology, 2018
Neil Herring, David J. Paterson
Osmotic pressure is a ‘colligative’ property, like freezing point depression; that is, it depends primarily on solute concentration, not chemical identity. The osmotic pressure (n) of an ideal solution is described by van’t Hoff’s law, namely
Effects of pesticide NeemAzal-T/S on thyroid, stress hormone and some cytokines levels in freshwater common carp, Cyprinus carpio L
Published in Toxin Reviews, 2022
Physical and chemical stimuli (heat, burning, toxic substance) coming from outside in organisms disrupt the ion balance of the cell. Thus, the cell acquires fluid and the organelles swell. Plasma and membrane integrity is disrupted and the cell bursts due to osmotic pressure. Following cell death, the release of cell contents into the intercellular space causes inflammation, and this inflammation is an important sign of necrosis. Toxic substances such as arsenic, cyanide, insecticides and heavy metals cause necrosis. Inflammation is an important factor that activates the release of cytokines. Cytokines are inducible cell peptides known to be of central importance in tissue regeneration, embryonic development, inflammation, and immune regulation (Ahne 1993). These are thought to be the main mediators of the regulation of immune physiology in vertebrates (Oppenheim and Shevach 1991). It has been shown that the immune physiology of teleost fish is mediated by cytokines similar to those of mammals (Ahne 1993).
Vision of bacterial ghosts as drug carriers mandates accepting the effect of cell membrane on drug loading
Published in Drug Development and Industrial Pharmacy, 2020
Fars K. Alanazi, Abdulaziz A. Alsuwyeh, Nazrul Haq, Mounir M. Salem-Bekhit, Abdullah Al-Dhfyan, Faiyaz Shakeel
The effect of different osmotic pressure was investigated over the range of 0.5, 0.6, 0.7, and 0.9% NaCl. The incubation media was composed of 30 mg ghosts with 300 µL of DOX (5 mg/mL). For this experiment, 5 mg/mL of DOX was preferred to control tonicity of drug solution. Two stock solutions was prepared, first solution was with tonicity of 1.8% NaCl and the second was DOX (10 mg/mL). Five hundred microliter was taken from stock solution of DOX (10 mg/mL) and 500 µL was tacked from tonicity stock solution (1.8% NaCl). It was reached to 1 mL of solution with tonicity 0.9% NaCl and DOX concentration of 5 mg/mL. After that, stock solution was adjusted for different tonicity using distilled water. After incubation for 140 min, samples were collected and treated as discussed in previous section.
Development and optimization of osmotically controlled drug delivery system for poorly aqueous soluble diacerein to improve its bioavailability
Published in Drug Development and Industrial Pharmacy, 2020
Magdy I. Mohamed, Abdulaziz M. Al-Mahallawi, Sami M. Awadalla
Osmotic pump Controlled Release Preparation is a novel drug delivery system. It gains a vital interest in oral solid dosage form development chiefly because of their ability to deliver drugs at constant rates (zero-order release) independent of media pH and hydrodynamics of the surrounding media [14,15]. Osmosis can be defined as the spontaneous movement of a solvent from a lower solute solution to a solution of higher solute concentration through an ideal semi-permeable membrane, which is permeable only to the solvent but impermeable to the solute [16,17]. The preparation consists of the core that contained the active material, a semi-permeable membrane that coated the core and an orifice, produced by a micro drill or mechanically to release the active material. When the system is in the gastrointestinal tract, fluid enters into the preparation and dissolves the active material within the core [14,17]. Thus the pressure formed in the preparation induces a release of the solution at a slow but continuous rate [18,19]. Therefore, solubility is considered one of the most vital factors affecting the drug release kinetics from the osmotic pump. As well as Osmotic pressure is another vital factor that imbibes water inside the osmotic pump, and it is proportional to the concentration of the osmotic agent [14].