Objective: During drug preformulation studies, thermal analysis and spectroscopic techniques are used to detect physical or chemical incompatibilities between the active compound and the excipients in the formulation, and to demonstrate the safety and/or efficacy of the final product. It has revolutionized erectile dysfunction with the development of a selective cyclic guanosine monophosphate-specific PDE-5 inhibitors. Tadalafil is one of these inhibitors. Excipients are included in dosage forms to assist in manufacture, absorption or application. Although considered to be pharmacologically inert, the drug active compound may impair effectiveness.
Material and Method: DSC, TGA, and FTIR, were used in the work. Ascorbic acid, butylated hydroxyanisole, calcium phosphate dibasic, cellulose, magnesium stearate, mannitol, sodium carboxymethyl cellulose, sucrose, talc, starch, primojel, and citric acid exhibit interaction with Tadalafil. Binary mixtures of drug:excipient have been analyzed.
Results: Based on spectroscopic and thermal results; Tadalafil is incompatible with magnesium stearate, mannitol, sucrose, and ascorbic acid.
Conclusion: Studies to investigate drug-excipient compatibility are an important step in drug development studies. Thermal and spectroscopic techniques are widely used in such studies.