Citric acid–polyethylene glycol–citric acid (CPEGC) triblock dendrimers as biocompatible compounds containing G1, G2 and G3 were applied as the drug-delivery systems. Some of the small size molecules and drugs are trapped with the above-synthesized dendrimers. The guest molecules, which are hydrophobic when trapped into the suitable sites of dendrimers, are becoming soluble in aqueous solution. The quantity of trapped molecules and drugs such as 5-amino salicylic acid (5-ASA), pyridine, mefenamic acid, and diclofenac was measured. The drug/dendrimer complexes remained in room temperature for about 10 months and after this long time they were stable and the drugs were not released. Also, the controlled release of the above-mentioned molecules and drugs in vitro conditions was investigated. The structure definition and controlled release of the molecules and drugs were carried out using different spectroscopy methods.