Peak action time

Nevertheless, the avena coleoptile exhibits a curvature to unilateral UV-illumina-tion with a satisfactory log-linear response/time relationship38) (the bending mode is similar to that observed for the second positive curvature which develops from the coleoptile base cf. 2.2). Fig. 5 338) shows that the double-peaked action spectrum does not match neither flavin (Fig. 5 5,16S)) nor carotenoid absorption (Fig. 5 4,183)), most likely excluding both as photoreceptors. The growth hormone auxin (cf. 2.4 and Scheme 1) has been discussed to be a possible photoreceptor. However, in this case, this is not supported by the action spectrum either. 

Some 25 anxiolytics and hypnotics are marketed at present the best known of these are listed in Table 1.10. Here, again., there are striking differences between the doses of these products, which can be explained m the same way as for antipsychotics. The benzodiazepine derivatives and related compounds show few qualitative differences nevertheless, the time effect features, i.e. the timing of onset of action and peak action as well as duration of action, mean that it is sensible to use different products for different purposes. 

Pharmacokinetics is the study, which determines the rapidity and concentration of the drug in the body and its duration of appearance at the target organ, i.e. onset, time of peak action and duration of action and by these also determine the route(s) and frequency of administration of drug. 

A composition based on diketopiperazine derivatives (3,6-bis (N-fumaryl-N-(n-butyl) amino-2, 5-diketopiperazine) has been investigated as a pulmonary drug delivery system, termed Technospheres (Pharmaceutical Discovery Corp., Elmsford, NY) (Pohl et al. 2000 Steiner et al. 2002). The diketopiperazine derivatives self-assemble into microparticles at low pH with a mean diameter of approximately 2 pm. During self-assembly, diketopiperazine derivatives microencapsulate peptides present in the solution. Insulin incorporated in diketopiperazine derivatives (TI) was administered to five healthy humans by the use of a capsule-based inhaler with a passive powder deagglomeration mechanism. Relative and absolute bioavailability of TI in the first 3 hours (0-180 min) were 26 12% and 15 5%, and for 6 hours (0-360 min) 16 8% and 16 6%, respectively (Steiner et al. 2002). The time to peak action for glucose infusion rates was shorter with both IV (14 6 min) injection and inhalation (39 36 min), as compared to SC administration (163 25 min). This rapid absorption of insulin would be beneficial for diabetic patients who need to rapidly affect their glucose levels. 

The dose of inhaled insulin is about 10 times higher than the subcutaneous dose that produces the same hypoglycemic effect. In an open, randomized, crossover study subcutaneous insulin was compared with a 10 times higher dose of inhaled insulin in 15 non-smoking patients with type 2 diabetes (262). The peak action of inhaled insulin was earlier. Apart from that, the effects were similar. There were no differences in FEVi at baseline or at 4 or 8 hours after treatment. Absorption of inhaled insulin is significantly higher in smokers (263). In non-diabetics, absorption is reduced in asthma (264). Inhaled insulin may increase the titer of insulin antibodies (265). 

For tests performed in whole aiumals, an activity kinetic study is highly recommended. It will allow determination of the time of the peak action and to compare the different molecules at the optimal time. 

In Chapter 2, we insisted that a correctly performed pharmacological study must satisfy certain criteria (relationship between dose and effect, presentation of the confidence limits, comparison with a reference compound, determination of the time of the peak action). On the chemical side it is also extremely important to provide pharmacologists with reference compounds published by the competitor laboratories. Even if it is felt tedious and time-consuming to resynthesize an already described compound, the operation is always worthwhile and sometimes surprising. How often a good-looking published molecule, for which attractive activities are claimed, loses much of its charm once it is reinvestigated by one s own team ... 

The nurse must also know the dmg s onset of action, peak action, and duration of action. As you ll recall from the previous chapter, onset is the time period when the dmg reaches the minimally effective concentration in the plasma. The peak action is when the dmg reaches the maximum concentration in the plasma. The duration is the length of time the therapeutic action will last. 

The aim of insulin replacement is to mimic the physiological pattern of insulin secretion. Conventional insulin preparations have in this respect some major pharmacodynamic pitfalls. The action of rapidly acting preparations is slower and of longer duration than the physiological meal time-stimulated insulin secretion. Preparations for basal use have peak action 5-8 h after a subcutaneous application. In addition, the absorption of intermediate-acting insulin varies a lot. 

Figure Bl.3.7. A WMEL diagram for the seventh order Raman echo. The first two field actions create the usual Raman vibrational coherence which dephases and, to the extent that inliomogeneity is present, also weakens as the coherence from different cliromophores walks oflP. Then such dephasing is stopped when a second pair of field actions converts this coherence into a population of the excited vibrational state / This is followed by yet another pair of field actions which reconvert the population into a vibrational coherence, but now one with phase opposite to the first. Now, with time, the walked-oflP component of the original coherence can reassemble into a polarization peak that produces the Raman echo at frequency oi = 2(o - (O2...

The AeroSizer, manufactured by Amherst Process Instmments Inc. (Hadley, Massachusetts), is equipped with a special device called the AeroDisperser for ensuring efficient dispersal of the powders to be inspected. The disperser and the measurement instmment are shown schematically in Figure 13. The aerosol particles to be characterized are sucked into the inspection zone which operates at a partial vacuum. As the air leaves the nozzle at near sonic velocities, the particles in the stream are accelerated across an inspection zone where they cross two laser beams. The time of flight between the two laser beams is used to deduce the size of the particles. The instmment is caUbrated with latex particles of known size. A stream of clean air confines the aerosol stream to the measurement zone. This technique is known as hydrodynamic focusing. A computer correlation estabUshes which peak in the second laser inspection matches the initiation of action from the first laser beam. The equipment can measure particles at a rate of 10,000/s. The output from the AeroSizer can either be displayed as a number count or a volume percentage count. 

Because we were unable to identify the methyl anthranilate component within the sensitivity of the equipment used for these tests, we resorted to an examination of the ethanol loss (Figure 11). After a sampling time of 65 hours for each sample, the sample of CC14 was injected. The amplitude of the peak at 1 minute 58 seconds retention time (peak for ethanol) was examined. The two tests proved that the corrective action on the container was effective. Less than 10 6 grams of ethanol (the sensitivity limit of the system) had escaped from the corrected sample container, whereas 1.5 X 10 4 grams of ethanol had escaped from the uncorrected sample. (See Figure 11, which shows the two traces.)... 

The nurse should check the patient for hypoglycemia (see Table 49-1) at the peak time of action of the insulin (see Summary Drug Table Insulin Reparations). Hypoglycemia, which can develop suddenly, may indicate a need for an adjustment in the insulin dosage or other changes in treatment, such asa change in diet. Hypoglycemic reactions can occur at any time but are most likely to occur when insulin is at its peak activity. 

In our example, for very small times the theoretical influence of b (given by its sensitivity coefficient) grows more slowly than the theoretical influence of a, while the theoretical influence of Vo (initially the only effective one) increases much more slowly than those of either a or b. Assembling these separate effects we have a combined situation in which the practical influence of a (measured by its MCCC) rises quickly while overcoming the influence of Vo, peaks when a is the only effective parameter, then decreases to reach a steady level as the action of b also asserts itself. 

Figure 5. Multiple actions of toxin II from Ammonia sulcata (ATX II) on voltage-clamped Na currents (Ij ) from amphibian myelinated nerve. This stabilizer toxin works in a dose-dependent manner to inhibit channel inactivation see bottom panel) and, as a consequence, delay the time of peak current see top panel). The reduction of peak current amplitude does not result directly from these kinetic alterations and is not observed with all stabilizers (Reproduced with permission from Ref. 39. Copyright 1981 SPPIF).

The speed of propagation of the action potential does not depend on the location of a working electrode in the stem of the plant [Figs. 19(a)-(c)] or in the tuber [Figs. 19(d) and 20], or on the distance between the working and reference electrodes (Fig. 21). The speed of propagation of the action potential induced by the Colorado potato beetle can be determined from the slope of the dependence of the time interval between peaks on the distance between electrodes (Fig. 21) and is about 0.05 cm/s. 

FIG. 21 The time dependence between positive and negative peaks of action potential induced by Colorado potato beetles on the distance between electrodes. The plants were given water every other day and kept at 20° C. A few electrodes were immersed in potato seed and different parts of the plant stem 2 h before measurements of the potential difference. (From Ref. 7.)... 

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