pH control agents and buffers:

If a specific pH value is found necessary to provide for optimum stability and / or to minimize solubility in the suspending vehicle, the system can be maintained at this desired pH value (as pharmaceutically acceptable buffer). This is especially important for drugs that possess ionizable acidic or basic groups; then the pH of the vehicle often influences drug stability and / or solubility. However, the use of salts and buffers should be avoided; science small changes in electrolyte concentration will often alter the surface charge of suspended particles. Such effects can influence the nature and stability of flocculated suspensions. This is especially noticeable when polyvalent ions, such as citrates and phosphates are used in buffering systems. Suspensions of stable neutral drugs, which possess no charge such as corticosteroids, are usually insensitive to pH change.