The dielectric constant of a solvent is defined as the ratio of the capacitances of a capacitor filled with the solvent or air.   Dielectric constant (e) = Csolvent/Cair   where C is the capacitance of the condenser filled with respective medium (solvent or air). Every solute shows a maximum solubility in any given solvent system at one…

Cosolvents are used to increase the solubility of weak electrolytes, nonpolar molecules and volatile constituents that are used to impart a desirable flavor and odor to the product. Weak electrolytes and nonpolar molecules have poor water solubility. These types of solutes are more soluble in a mixture of solvents than in one solvent alone. This…

An excess amount of drug is placed in a vial along with a specific amount of the solvent. The tightly closed vial is then agitated at constant temperature and the amount of drug in solution is determined by a suitable analytical method. The solubility is generally expressed in mg of solute per ml of solvent…

Solubility When a solute is dissolved in a solvent, two types of interactions are possible. One is the intramolecular force of attraction between the solute molecules and the other is the intermolecular force of attraction between the solute and solvent molecules. When a solute dissolves, the intramolecular force or cohesive force must be overcome by…

Solutions are classified on the basis of the following aspects (Figure 6.1): Figure 6.1 Classification of Monophasic Liquid Dosage Forms

The following are the important characteristics of a solution: Advantages The advantages of a solution are as follows: Disadvantages The disadvantages in using a solution are as follows:

Learning Objectives A solution is a homogenous mixture composed of only one phase. In such a mixture, a solute (drug substance) is dissolved in another substance, called a solvent. The concentration of a solute in a solution is a measure of the amount of solute dissolved in that solvent.