Burst-effect

When Jencks reacted hydroxylamine with p-nitrophenyl acetate, p-nitrophenolate ion was released at a rate faster than that at which acetohydroxamic acid was formed. This burst effect is evidence for a two-step reaction. In this case the intermediate is O-acetylhydroxylamine, which subsequently reacts with hydroxylamine to form the hydroxamic acid. 

W,. = effective charge weight in pounds of TNT for estimating surface burst effects with free air. 

W = required vapor capacity in pounds per hour, or any flow rate in pounds per hour, vapor relief rate to flare stack, Ibs/hr W(. = charge weight of explosive, lb Wj. = effective charge weight, pounds of TNT for estimating surface burst effects in free air W, = required steam capacity flow or rate in pounds per hour, or other flow rate, Ib/hr Whe = hydrocarbon to be flared, Ibs/hr Wtnt equivalent charge weight of TNT, lb Wl = liquid flow rate, gal per min (gpm)... 

An initial burst effect was observed in all in vivo studies. There are several possible factors which may cause a burst effect physically absorbed free drug, surface effects, and local tissue inflammation during the initial period of injection. It has been shown that inflammation decreases local tissue pH (15,16) and causes release of hydrolytic enzymes which would increase the hydrolysis of labile bonds, thereby increasing the release of the drug and, subsequently, increasing plasma levels of drug. 

Fig. 6 Plot showing the approach to steady state for a reservoir device that has been stored for an extended period (the burst effect curve) and for a device that has been freshly made (the lag time curve). (From Ref. 29.)...

Atomization Unknown, but Plausibly Aerodynamic Interaction, Turbulence, Cavitation, Bursting Effect We >40.3 or Oh lOORei 092 [220] ... 

Hexotonal has been manufd by AB Bofors for use as a cast filling at d 1.68-1.74. Its sensitivity to impact and friction is moderated by an addn of wax, its sensitivity to initiation is comparable to that of Hexotol, but bursting effect and fragmentation power are higher (Ref 3, p 203)... 

The release curve of ketoprofen obtained from the KET-R tablet at pH 1.2 and 50 rev/min is shown in Fig. 1. The release profile was zero order up to 90% drug content. The equation obtained by plotting the percentage released vs. time was y=0.187x-1.997, 0.99. No burst effect was present. 

In several cases, a fit of equation (2) to the data was not statistically significant, or the residuals indicated systematic deviations due to strongly curved release profiles. Then, alternatively a fit of equation (3) was tried in order to be able to describe tendencies which occur on variation of matrix composition. In all cases the first time interval was not considered, as burst effects are to be expected which are not representative for long-term drug release. 

Air-burst effects of the blast from bpmbs and small charges 1 All 6 >... 

Solutions (lavages) and foams are liquid preparations. The foams differ from the solutions in the presence of a suitable propellant, in the formulation, and the type of container, a pressurized delivery device. Plasma concentration profiles obtained after solution administration are characterized by a burst effect followed by a rapid decrease below therapeutic levels, due to the low residence time of the formulation in the vaginal cavity. Such preparations are designed to achieve a local effect particularly in case of inflammations or infections caused by bacteria or yeasts (anaerobic bacteria or Candida species). Nonoxynol-9 (N-9) foam is used as a contraceptive and against sexually transmitted diseases [19]. 

Figure 4.2 Released amount Qt versus time t plots. Illustration of time lag tL and burst effect tB in a reservoir-type diffusion-controlled drug delivery system.

Equation (6.40) is called the burst-effect equation, with a burst-effect time (tbiirsl)... 

Dhoot, N. O., and Wheatley, M. A. (2003), Microencapsulated liposomes in controlled drug delivery Strategies to modulate drug release and eliminate the burst effect, /. Pharm. Sci., 92(3), 679-689. 

Uses Lead-TNP is used in initiating compositions in place of lead styphnate or diazodinitrophenol for blasting caps and detonators, in priming compositions in place of mercury fulminate or in combination with sulfur nitride, triazoles, or tetrazoles, for use in bullet primers and the like. Lead-TNP can also be used in fireworks to detonate black powder for increased bursting effects in aerial shells. Lead-TNP should be handled with care. Never store dry, and keep submerged in a water free solvent... 

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