Dependence of the Release

Excitation-secretion coupling is a highly calcium-dependent process, and thus the calcium dependency of evoked release could be 

---

LuneU E, Molander L, Andersson SB (1997) Temperature dependency of the release and bioavaU-ability of nicotine from a nicotine vapour inhaler in vitro/ in vivo correlation. Eur J Pharmacol 52 495-500... 

Recent work by Carter et al. (2002) on the alteration of hollandite samples in pure water at 90 °C and 150 °C demonstrates that the release rates of Ba and Cs are nearly identical. In these same experiments, Al and Ti are below detection limits at 90 °C and only Al is detected at 150 °C, but only by a factor of 2-3 above the detection limit. These authors also examined the pH dependence of the release rates at 90 °C, finding that the release of Ba decreases linearly (Fig. 8) from about 2 x 10-3 g/m2/d at pH = 2.5 to 4 x 10-4 g/m2/d at pH = 12.9. SEM work revealed the presence of nodular secondary phases on the surface of the hollandite at both temperatures. This was confirmed by XTEM work on cross-sections of the material, which identified both Ti-rich and Al-rich nodules in a ratio of about ten to one, respectively. Furthermore, XPS analysis of the hollandite surface after testing at 150 °C for 7 days showed an increase in the Al/Ti ratio from 0.26 to 0.47, consistent with the presence of an Al-rich layer approximately 0.5 nm thick. XPS results also show a decrease in the Ba/Ti ratio from 0.095 to 0.072 and this is equivalent to removal of about 25% of the Ba within 5 nm of the surface. 

Figure 6. Temperature dependence of the release rate of formulation A aged 7 days in the wind tunnel at a wind velocity of 26.9 m/min.

DLTS experiments are performed either by measuring the temperature dependence of the capacitance at a fixed time after the application of the reverse bias or the time dependence is obtained at constant temperature (Johnson 1983). The result is an equivalent measure of N E), but the exponential dependence of the release time on energy in Eq. (4.17) means that a wide range of times are needed to measure the full energy range. Figs. 4.17 and 4.18 show examples of the density of states distribution for n-type a-Si H obtained using both techniques. A broad defect band 0.8-0.9 eV below (, is observed. 

All HPMC samples had similar viscosity, except batch 7 which is outside USP specifications (75-140% of the nominal value 15000). Methoxyl contents are uniformly high and three batches fall outside the USP specifications 19-24%. Hydroxypropyl contents, although within the specified limits (4-10%), vary relatively more than methoxyl contents, with batch 5 showing the lowest value. When measuring the release of the drug naproxen from compressed matrix tablets, the authors observed in vitro a strong dependence of the release rate (expressed in h ° s ) on the hydroxypropyl content of the HPMC (Fig. 1). 

The relevance of the control of the reverse micelles and dependence of the release kinetics on the reverse-micelles concentration and size was demonstrated. The amount of solubilized water in the oil phase, as a function of Span concentration, was measured (after centrifugation). It was found that water is present only in very minor quantities when the siliconic emulsifier is employed by itself. The water concentration increased as the amounts of Span 80 were raised (87). These findings are also in good correlation with the release rates and the lag time. 

About pseudo normal type diffusion MS also shows kinetic curves, constructed in coordinates G/G -t (Fig. 13.2). In the case of simple diffusion, the dependence of the release of the MS from film samples in coordinates G/G -t -would have to be straightened at all times of experiment. However, as can be seen from (Fig. 13.2) a linear plot is observed only in the region G/G < 0.5, after which the rate of release of the antibiotic significantly decreases. 

FIGURE 8.6 Dependence of the released heat rate, gpc = j [-T SKnF) - T pc + Fc/I> generated electric power density, = y pc. and potentials difference, of the PEMFC described earlier and represented by Figure 8.4 —Curve 1 Ppp.—curve 2 gpc—curve 3. 

---