Plasma initial, determination

Inject subcutaneously or IM when possible. In older children and adults, inject IM in the upper outer quadrant of the buttocks. In infants and young children, the anterolateral aspect of the thigh or the deltoid region is preferred. When IV administration is unavoidable, inject very slowly, not exceeding 1 mg/min. Anticoagulant-induced prothrombin deficiency in adults 2.5 to 10 mg or up to 25 mg (rarely, 50 mg) initially. Determine subsequent doses by prothrombin time (PT) response or clinical condition. If in 6 to 8 hours after parenteral administration (or 12 to 48 hours after oral administration), the PT has not been shortened satisfactorily, repeat dose. If shock or excessive blood loss occurs, transfusion of blood or fresh frozen plasma may be required. 

Monomers Polymerizable by Plasma Initiation. Polymerization data for all of the vinyl monomers utilized in this study are summarized in Table 1. As shown previously, methyl methacrylate is readily polymerizable (, ). Methacrylic acid (MAA) and acrylic acid (AA) are polymerized immediately upon exposure to the plasma. Because the resulting polymers are insoluble in their monomers, the products are precipitated out and conversion is low despite prolonged post-polymerization. However, if water is now added as solvent, polymerization becomes homogeneous and high conversions can be readily achieved with post-polymerization. For example, after a 15 second plasma initiation period more than 80% yield was obtained for a 75% aqueous solution of MAA. The molecular weight, determined by intrinsic viscosity measurements, was found to be 4.5 X 10 gm/mole. 

Sub-crystal fractions in PTOX from both radiation and plasma initiated polymerizations were determined from the (100) reflections and summarized in Table 2. Their values are somewhat, but not substantially, lower for the plasma samples than for the radiation samples. However, since the amount of subcrystal fraction depends on both the temperature and the yield, meaningful comparisons between these two types of samples are difficult on the basis of these rather limited data. 

Analytical Techniques. The primary method used to determine the metallic element concentration in the tailings was IX Plasma Atomic Emission Spectrometry (IXP). It was used for the determination of both major and minor components. In the former case, the analysis is straightforward, but in the case of minor constituents, it was necessary to use matrix matching, i.e., to use standard solutions having the same concentration of the major component as the unknown, to compensate for the background emission interference of the other solutes. This requires the initial determination of the major components to define the appropriate doping levels. The... 

By means of OH- and COOH-containing plasma polymer layers the quahfica-tion of these layers as models of single-type functionalized adhesion promoters with variable concentrations of functional groups should be proved. The plasma-initiated copolymerization of acrylic acid with ethylene or 1,3-butadiene is shown in terms of measured COOH concentration as a function of the composition of the comonomer mixture in Fig. 18.3. Depending on the co-monomer reactivity, a more linear correlation (butadiene), or a parabolic behavior (ethylene), between precursor composition and COOH groups produced was observed. For each type and concentration of functional group, its concentration was determined by chemical derivatization followed by XPS analysis as described in Section 18.2.5. 

Levonorgestrel blood plasma levels determined by radioimmunoassay showed a reasonably constant level for one year, once the initial burst subsided. However, the steady state plasma level was too low and thus a more rapidly eroding polymer was needed. To achieve a more rapid erosion, a material containing 7 wt% Mg(OH) 2 and 1 mole% copol nmerized 9,10-dihydrox) stearic acid was prepared. The detdces were again implanted into rabbits and levonorgestrel blood plasma level determined. Results of these studies have shown a much higher, satisfactory drug pltisma level (Heller, 1993). 

The initial enthusiasm for tacrine and velnacrine, which are the anticholinesterases most studied clinically, has been tempered by the fact that not all patients respond. Most show the peripheral parasympathomimetic effects of cholinesterase inhibition, e.g. dyspepsia and diarrhoea, as well as nausea and vomiting, and about half of the patients develop hepatotoxicity with elevated levels of plasma alanine transaminase. While some peripheral effects can be attenuated with antimuscarinics that do not enter the brain, these add further side-effects and the drop-out rate from such trials is high (<75%) in most long-term studies. Donepezil appears to show less hepatotoxicity but its long-term value remains to be determined. 

Figure 39.4a represents schematically the intravenous administration of a dose D into a central compartment from which the amount of drug Xp is eliminated with a transfer constant kp. (The subscript p refers to plasma, which is most often used as the central compartment and which exchanges a substance with all other compartments.) We assume that mixing with blood of the dose D, which is rapidly injected into a vein, is almost instantaneous. By taking blood samples at regular time intervals one can determine the time course of the plasma concentration Cp in the central compartment. This is also illustrated in Fig. 39.4b. The initial concentration Cp(0) at the time of injection can be determined by extrapolation (as will be indicated below). The elimination pool is a hypothetical compartment in which the excreted drug is collected. At any time the amount excreted must be equal to the initial dose D minus the content of the plasma compartment Xp, hence ...

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