Solubility and Dissolution Principles
Start with the big picture
Solubility describes the equilibrium amount of a substance that can dissolve under specified conditions, including temperature and pH. Dissolution is the process of moving into solution, and its rate depends on factors such as surface area, the concentration gradient, and the diffusion layer. The lesson examines the Noyes–Whitney relationship and intrinsic dissolution rate, then relates solubility and permeability through the Biopharmaceutics Classification System. It also surveys how ionization, salt formation, cosolvents, surfactants, particle size, and solid-state form can affect solubility or dissolution. Ionic effects and supersaturation provide further context for precipitation, while dissolution testing connects these concepts to quality control and pharmaceutical performance.
What you'll learn
- Distinguish equilibrium solubility from dissolution rate.
- Describe factors in the Noyes–Whitney relationship that influence dissolution.
- Explain how pH, ionization, and formulation strategies can alter apparent solubility.
- Relate solubility and permeability to the four BCS classes.
- Identify how solid-state properties and dissolution testing inform pharmaceutical performance.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
