Burst release phenomenon

The osmotic pressure phenomenon manifests itself in many interesting applications. To study the contents of red blood cells, which are protected from the external environment by a semipermeable membrane, biochemists use a technique called hemolysis. The red blood cells are placed in a hypotonic solution. Because the hypotonic solution is less concentrated than the interior of the cell, water moves into the cells, as shown in Figure 12.14(b). The cells swell and eventually burst, releasing hemoglobin and other molecules. 

They show some physical instability and early burst releases of encapsulated drugs as proteins or water-insoluble drugs as ibuprofen. This phenomenon could be due to the location of a part of the associated drug at the outer surface of the particles or by the presence of surfactants at the interface. 

The failure of the fuel rod claddings in the temperature region of 1000 °C ( 1300 K) is accompanied by the burst release of fission products, the same phenomenon which transports the fission products into the primary circuit in... 

Above reaction usually occurs under following conditions, e.g., unsealed explosive device, no booster, incomplete detonation reaction, such reaction may produce half-burst phenomenon and release a large amount of N2O. The reaction of nitroglycerine without any condition above can be described as follows ... 

Theory The release under shear of an active molecule that is initially encapsulated in the aqueous phase of a W/OAV multiple emulsion is a very promising phenomenon for applications in cosmetics or pharmaceuticals. Taylor (Taylor, 1932, 1934) was first to study the deformation of molecules under shear and their bursting in a simple, dilute emulsion. He considered that breakup occurred when shear stress exceeds cohesion stress. He defined this breakup by way of a capillary number, Ca ... 

Another method of pilocarpine release is the use of a thin laminate of hydrophile polymers inserted in the conjunctiva cul-de-sac. This pilocarpine Ocusert system releases pilocarpine at a constant pre-determined rate. The sustained-release system, providing such advantages as maximum duration of pressure control, less round-the-clock pressure variation, use of smaller drug concentrations with decrease of ocular and systemic side effects, also has some disadvantages one problem is the burst phenomenon, in which there is a large initial release of pilocarpine after insertion, resulting in severe miosis and ciliary body spasm. Up to the present several cases of loss of device and 8 -formation, comeal erosion, subconjunctival bleeding and displacement to the pupil have been reported. 

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