Cumulative drugs

Define drug tolerance, cumulative drug effect, and drug idiosyncrasy. 

A cumulative drug effect may be seen in those with liver or kidney disease because these organs are the major sites for file breakdown and excretion of most... 

FIGURE 9 Effect of drug loading on cumulative drug release from polymer discs prepared from 3,9-bis(ethylidene-2,4,8,10-tetraoxaspiro-[5,5]undecane) and a 50 5Q mole ratio of trans-cyclohexane dimethanol and 1,6-hexanediol at pH 7.4 and 37 C. Drug loading 8 wt% (o),... 

In vitro dissolution was virtually complete after 6-8 hr. Since the plot of cumulative drug release versus time is hyperbolic, the authors attempted to fit the data to the Higuchi matrix dissolution model (116,117), which predicts a linear correlation between cumulative drug release and the square root of time. Linearity occurred only between 20 and 70% release. 

Vertzoni M, Symillides M, Iliadis A, Nicolaides E, Reppas C. Comparison of simulated cumulative drug vs. time data sets with indices. Eur J Pharm Biopharmac 2003 56 421—428. 

In many cases, transdermal drug absorption is investigated using a Franz-diffusion cell. The concentrations both in the membrane and the acceptor compartment are assumed to be zero at the start of the experiment. At different time points, the cumulative drug amount per unit area in the receptor q(t) is determined and plotted versus time t (Figure 20.1). After some time, the flux... 

To develop an HPLC stability-indicating method for Type I or II dissolution, the linearity must be wide enough, in combination with good sensitivity and minimal interference, to accommodate concentrations from low (possibly LOQ) to very high end, as the samples drawn represent the cumulative drug amount dissolved over time. As for an FiPLC method that is designed for Type VII dissolution, the linearity should accommodate the lower concentrations since it is a drug measurement of a controlled-release system. 

The drug release profile was plotted against time (Figs. 4 and 5) and it was observed that the release kinetics followed both first-order and Higuchi equations up to 75-80% of the cumulative drug release. The micromatrices followed the Higuchi equation (NONLIN package). 

Equation 7.10 is obtained by integration of Equation 7.1 and evaluation of the integral over the interval from t0 to U. AUC is a measure of the cumulative drug... 

Figure 2. The cumulative amount of drug diffusing through skin is graphed versus time. Normally, the cumulative drug diffusion is directly proportional to time. The presence of an air bubble under the skin or a hole in the skin results in deviations from this behavior.

FIGURE 6.8 Cumulative drug release from a membrane-reservoir sphere (time lag). 

The cumulative drug release and the drug release rate for constant activity and nonconstant activity reservoirs of other geometrical barriers are shown in Table 6.3. 

The Cumulative Drug Release and Release Rate for Constant Activity and Nonconstant Activity Reservoirs... 

Vertzoni, M., Symillides, M., Iliadis, A., Nicolaides, E., and Reppas, C., Comparison of simulated cumulative drug versus time data sets with indices, European Journal of Pharmaceutics and Biopharmaceutics, Vol. 56, No. 3, 2003, pp. 421-428. 

THERAPEUTIC RESPONSE, CUMULATIVE DRUG EFFECTS, AND SCHEDULE DEPENDENCE... 

Figure 7.17 Tablet erosion (circles) and cumulative drug absorption (diamonds) for a hydrophilic matrix ER tablet after administration under fasting (a) and non-fasting (b) conditions in one subject. The two dashed vertical lines represent gastric emptying and colon arrival, respectively. The figures illustrate the correspondence between tablet erosion and drug absorption. In addition, the figures also show that the more rapid absorption after intake with food is caused by an increased erosion rate (Abrahamsson 1998b).

The equation for cumulative drug release from an credible cylinder shaped device with radius r and length h is given by Eq. (1) ... 

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