Pharmaceutical chemistry is a branch that includes synthetic organic chemistry, pharmacology and biological specialties, where they involve in the design of drugs, synthesis and development. Pharmaceutical chemistry focuses on small molecules / organic entities encompassing synthetic organic chemistry, aspects of natural product chemistry and computational chemistry in close relation with chemical biology, enzymology and structural biology, together with the goal of discovery and drug development of new different agents. Speaking in practical terms, it involves chemical aspects of identification and, subsequently, a systematic and exhaustive synthetic alteration of new chemical entities to make them appropriate for use. It includes synthetic and computational aspects of the study of drugs and agents existing in the development in relation to their biological activities to understand their structure-activity relationship (SAR). Pharmaceutical chemistry focuses on the aspects of medicines and aims to ensure the adequacy, efficiency of the purposes of the medicines.