### Using the Volume of Distribution to Calculate Dose Size

Notice that the main skill required for these calculations is the appropriate use of units. Make sure that at all stages, you use the correct......

### Dose Calculation of Volume of Distribution

A new patient is to be treated with theophylline (actually administering its salt aminophylline; S = 0.8). He is of fairly normal build and weighs......

### Explain Volume of Distribution Blood into Tissues

The four factors discussed above will jointly govern the extent to which drug moves out of blood into tissues. Below Figure summarizes the spectrum of......

### Describe the Extent of Distribution of Tissue

Four factors govern the extent to which drugs move out of the blood into tissues: Ability to undergo passive diffusion Binding to macromolecules P-glycoproteins Ion......

### Describe One and Two Compartment Model of Blood

The simplest model allows for instantaneous distribution of drug throughout the blood (and probably to some extent tissues), but this is not then followed by......

### Explain rate of Distribution and Compartments in Terms of Tissues

Below Figure shows drug passing backwards and forwards between blood and a series of different tissues. It is assumed that drug will distribute into and......

### Describe Salt factor in terms of Bioavailabilty

In addition to bioavailabilty, dose calculations may also need to be adjusted for a so called ‘Salt factor’. This arises when a drug is administered......

### Significance of Bioavailability in Clinical Practice and Drug Development

In clinical practice, knowledge of the bio-availabilty of a drug is obviously important for dose calculation. If we administer a dose of drug (D) to......

### Explain Bioavailability from IV and Oral Routes

We have already seen that iv injection is special, as it is the only route where no absorption stage is required. As a result of......

### What is Bioavailability?

Apart from the rate of a drug’s absorption, we also need to consider the completeness of its absorption. Bioavailability is used to report this and......

### Describe Rate of Drug Absorption and Absorption Rate Constant

The speed at which the various processes within ADME occur are described by a series of rate constants. The usual assumption is that the rate......

### Explain Passive Diffusion by Which Drugs May Cross Biological Membranes

Assuming a drug is not injected intravenously, it will have to cross biological membranes in order to reach the blood from its initial site of......