Intermolecular Interactions
, where V = volume, n = number of moles, R = gas constant, T = temperature, and P = pressure. Consider the liquid state of water: according to the…
Disperse Systems – Coarse Dispersions – Suspensions and Emulsions
Figure 7.1 Illustration of a suspension Typically, suspensions are coarse dispersions consisting of solid particles (100–50000 nm in diameter) in liquid dispersion media. Particles and potential energy To briefly review, when…
Interfacial Phenomena
Figure 5.1 A simple interaction between a liquid and vapor or air A pure liquid in a container (such as a beaker) with a vapor phase above the bulk liquid. A…
Pharmaceutical Solvents
The qualifying statement leads to the following extended definition: ‘If all components are in the same physical state, the component present in the greatest proportion is considered the solvent for…
Polymers and macromolecules
Scheme 7.1 The spectrum of uses for polymers in pharmaceutics 7.1.1 Definitions Polymers are substances of high molecular weight made up of repeating monomer units. Substances with short chains containing relatively few…
Drug stability
Scheme 3.1 Examples of chemical groups susceptible to hydrolysis. Drugs that contain ester linkages include acetylsalicylic acid, physostigmine, methyldopate, tetracaine and procaine. Ester hydrolysis is usually a bimolecular reaction involving acyl-oxygen…
The solubility of drugs
Figure 4.1 Diagrammatic representation of the three processes involved in the dissolution of a crystalline solute: the expression for the work involved is w22 + w11 − 2w12 (solute–solvent interaction in the last stage is…
Emulsions, suspensions and related colloidal systems
Figure 6.1 Photomicrographs of (a) an oil-in-water emulsion and (b) a suspension. Table 6.1 Main types of colloidal systems Type Disperse phase Continuous phase o/w emulsion Oil Water w/o emulsion Water Oil…
Parenteral routes of drug administration
Clinical point IA injection of BCNU (carmustine; bis-chloronitrosourea) in the treatment of malignant glioma results in levels of drug that are four times greater than those following IV infusion, but…
Physicochemical properties of drugs in solution
Concentration is often given in grams per litre (g L−1) rather than kilograms per cubic metre (kg m−3). Note also that 1 mg mL−1 is therefore also equal to 1 kg m−3. Molarity is commonly expressed…
