Examples of pH-adjusting excipients that can be used to improve the dissolution rate of weakbasic drugs include organic acids (e.g., citric acid, tartaric acid and carbonic acid). After disintegrationof a solid dosage form, the organic acid dissolves in the surrounding gastric juices and lowers the pHof the stagnant diffusion layer surrounding each drug particle, creating a desirable environment for thedissolution and consequently the absorption of alkaline drugs. Acidic drugs, on the other hand, wouldexhibit an improved solubility as well as dissolution rate in an alkaline micro-environment since theywill exist more in the ionized state [28–30]