Compatibility study between lipoic acid with polymers used in controlled drug release systems

Lipoic acid is derived from octanoic acid and is considered a universal antioxidant for combating free radicals and regeneration of endogenous antioxidant, as well as acting like an essential cofactor in multienzyme mitochondrial complex. In the pharmaceutical field, the polymers are among used excipients in pharmaceutical technology, especially in therapies controlled release of drugs. The aim of this study was to evaluate the drug–excipient compatibility between the AL and excipients used in controlled release drug delivery systems. To investigate the possible interactions between substances, was initially performed one screening with differential scanning calorimetry (DSC) to detect possible interactions, and analyses were performed by infrared spectroscopy (FTIR) to confirm the possible interactions. Based on the results of DSC and FTIR was found to be incompatible only with PVP-K30. Based on these results, we can conclude that the analytical tools used in this study are effective for defining incompatibilities between drugs and pharmaceutical excipients in order to ensure a new formulation with well-defined parameters of quality control and stability.