Effect of Co-solvent on the Solubility of a Sparingly Soluble Crystal

Solubility data plays an important role in the industry. Measuring solubility of crystal in various solvent is a key factor in compound characterizing during the whole discovery and development process where it allows engineers to design and optimize crystallization process. Benzoic acid is a simple aromatic carboxylic acid, a colorless crystalline solid that is widely used in the pharmaceutical area, plasticizers, food preservative and niche in the lab use. This chemical shows low aqueous solubility and dissolution rate and this has become the main concern in the industry that require dissolution of this chemical. This research describe an approach to improve the solubility of benzoic acid by using co-solvent. The experiment was conducted in different percentage of co-solvent and at different temperature. Co-solvent solution is prepared by using glycerol in water by volume ratio. Benzoic acid is placed in the solvent and was let to stir for three hours. Three milliliter of solution was taken out and placed in a vile to let it dry at room temperature. Result shows the relation between solubility in different co-solvent and temperature whereby as the percentage of glycerol added increase, the solubility of benzoic acid increase. Same trend was depicted in term of solubility relation with temperature, as the temperature increase, amount of benzoic acid dissolve also increase. The analyses has shown that co-solvent is an effective method in increasing the dissolution rate of a sparingly soluble chemical and temperature plays important role in increasing the solubility. The main reason of conducting this study is because of the lack of literature data on the reaction between benzoic acid and glycerol.