Lieu of an Introduction

Intuitively such delivery systems or excipients would best achieve this objective if they were to be composed of natural products or their modifications an overwhelming presence of excipients under this category (discussed in Ref. 1) provides credence to this observation. The substitution of natural products comprising complex proteins, antibodies, chimera, or toxins in lieu of stand-alone simple inorganic molecules as excipients for parenteral drug delivery represents a paradigm shift in the introduction of emerging excipients in the therapeutic armamentarium. 

Extension of theory often requires introduction of empirical models and parameters in lieu of terms that cannot be rigorously calculated. Good accuracy is expected in the region where the model parameters were fitted to experimental data, but only limited accuracy when an empirical model is extrapolated to other conditions. For example, a simplified theory suggests that vapor pressure should have the form... 

The most recent introduction (1991) of NTG is as an intravenous infusion dosage form. It is being used in patients with CHF, unstable angina especially when accompanied by acute Mis, preoperative hypertension, and postoperatively in cardiac surgery. In this form NTG acts as fast as nitroprusside and, of course, has a short life so that effects can be controlled almost by the minute. The fact that no CN or SCN is produced may be an advantage. Finally, an aerosol NTG (nitrolingual) product in lieu of SL tablets for very rapid onset is now available. 

As discussed in the introduction section, it is also possible to measure the effects of applied electric fields directly on the kinetics of primary charge separation. This is a difficult experiment with an isotropic sample [6], and although improved experiments are currently in progress, no new results are available yet. In lieu of such direct measurements, indirect information can be obtained from measurements of field effects on the quantum yield of intermediates. The results are discussed in detail elsewhere... 

An alternative method to conventional thin-film techniques is the colloidal method. Typically, the catalyst layers are applied as a solution. It is well known that Nafion forms a solution in solvents with dielectric constants greater than 10. When a solvent which has a dielectric constant of 5.01 is employed as the solvent, a colloid forms in lieu of a solution. Shin et al. (2002) suggested that in the conventional solution method the catalyst particles could be excessively covered with ionomer, which leads to under-utilization of platinum. In addition, it was proposed that in the colloidal method the ionomer colloid absorbs the catalyst particles and larger Pt/C agglomerates are formed. The colloidal method is known to cast a continuous network of ionomer that enhances proton transport. The thickness of a catalyst layer that Shin et al. (2002) formed by the colloidal ink was twice that of the 0.020 nun thick layer formed with solution ink, In addition, the size of Pt/C agglomerates increased from 550 to 736 nm with the introduction of the colloidal method. The colloidal method dramatically outperformed the solution method at high current densities in single cell experiments. 

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