Novel drug-drug co-amorphous systems of olaparib with nonsteroidal anti-inflammatory drugs with improved solubility, physical stability, antitumor activity and pharmacokinetics

Olaparib (OLA), the first FDA-approved PARP inhibitor, has been approved successively for monotherapy or maintenance treatment of ovarian, breast and pancreatic cancer. Unfortunately, the poor solubility and bioavailability of OLA have limited its application. In this study, novel drug-drug co-amorphous systems of OLA with five nonsteroidal anti-inflammatory drugs (NSAIDs), including flurbiprofen (FLU), ketoprofen (KET), ibuprofen (IBU), diclofenac (DIC) or indomethacin (IND), were prepared for improving the aqueous solubility of OLA and achieving combination therapy against ovarian cancer. These new co-amorphous products were confirmed by powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Five co-amorphous systems were more soluble and released faster than the crystalline OLA in pH 6.8 buffer, and OLA-DIC and OLA-IND showed superior physicochemical stability under accelerated storage conditions. The antitumor activities of OLA-FLU, OLA-KET, OLA-IBU and OLA-DIC against OVCAR3 cell line were approximately increased by 3.5, 2.4, 2.7, and 6.0-fold than that of OLA, respectively. Moreover, pharmacokinetic studies of co-amorphous OLA-DIC in rats revealed that the OLA exhibited 6.14-fold improvement in AUC0-tvalue compared with crystalline OLA. Therefore, our study suggested that OLA-NSAIDs co-amorphous systems showed the great potentials to improve the solubility, dissolution behaviors, and bio-pharmaceutical performance of OLA.