Additivity of drugs

Again, it is important to reiterate one important fact, only free antibiotic is measured. Bound residues are rarely measured directly using these assays. Another problem with all such assays is the supplementation system. The assumption that the simple addition of drug to a matrix followed by analysis was reflective of the problems of assaying for antibiotic residues is simplistic and does not address the overall problem of assaying for antibiotic residues. 

Incubation conditions, timing of the addition of drug or drug concentrations that are insufficient to exert cellular effects. 

Nausea Usually transient and dose-related. May improve with dose reduction or symptomatic measures (e.g., food, antacids, addition of drugs that block 5-HT 3 receptors, such as cisapride). There has been increasing concern about using cisapride in combination with antidepressants that can substantially inhibit CYP 3A3/4 (i.e., fluvoxamine, nefazodone). The reason is that high levels of cisapride can cause arrhythmias as a result of delayed intracardiac conduction. 

At times, extemporaneous addition of drug to a ready-to-use emulsion (e.g., L payaiy not be the preferred way of developing formulations. This can be explained in view of the following reasons ... 

Extemporaneous addition of drug, alone and/or in solvent, has the tendency to damage emulsion droplets, sometimes resulting in permanent loss of its physical stability. 

This phenomenon is not fully understood however, it may be described as the formation of minute particles of the solute, which act as nuclei for further deposition of the solute from a supersaturated solution. The probable mechanism is bimolecular addition of drug molecules, X, and may be represented as follows ... 

The increase with time in the incorporation of radioactivity into DNA is linear between 30 and 90 min of the concomitant addition of drug and tritiated thymidine and during this time the specific activity of the acid soluble nucleotide pool remains constant and identical to that of the supplied [3H]thymidine. 

High Loading Nanoparticles are prepared directly from preformed drug-amphiphilic CD complexes and further loaded by the addition of drug solution in the organic phase. 

Prepare a concentrated Stock A (3.0 mg/100 pi) of cw-platin from which Stocks B-I will be prepared Table 6.5 details the preparation of your Stocks for this experiment. To efficiently prepare your solutions in a timely fashion to minimize DMSO exchange (see Experiment 6.2), label 11 150 pi conical vials A-K. Add the appropriate volume of DMSO solvent indicated in column 6 to each vial. Prepare Stock A. Quickly make serial dilutions as indicated in Table 6.5, vortexing for rapid mixing (recall the rapid substitution kinetics of cwplatin in DMSO—Experiment 6.2 ). Note that the drug STOCK labels are identical to the well labels. After the addition of drug and medium the total volume in each well is 3.5 ml. 

A very common and powerful application is creating an inducible allele of a protein in order to dissect its function. Typically, the protein of interest is fused to a dimerization domain, cells expressing the fusion protein are exposed to dimerizer, and the consequences are assessed by any appropriate technique, such as assaying downstream signaling or profiling mRNA expression. The key advantages of chemically induced dimerization are that activation can be restricted to one particular protein and can be initiated and then monitored in real time by addition of drug. This allows very specific questions to be asked about the function of a protein or of the pathway that it controls. 

Stepped care in hypertension Progressive addition of drugs to a regimen, starting with one (usually a diuretic) and adding in stepwise fashion a sympatholytic, a vasodilator, and (sometimes) an ACE inhibitor... 

The addition of drug manipulability to an already genetically tractable model greatly increases the experimental scope of this migration assay. 

The changes in phase transition of artificial bilayers for example upon addition of drugs is only a parameter which allows an interpretation of strength and type of interaction with the studied phospholipid and is useful for the derivation of quantitative structure-interaction relationships. 

The reduction in T, is independent of the phospholipid/drug ratio. This means that the phospholipid/drug domains possess a constant composition. The domain becomes enlarged upon addition of drug (increase in area under the signal of the thermogram), but no change in structure or "quality" occurs. 

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