2.7.2. Intrinsic Dissolution Rate (IDR) Test

IDR is a key physicochemical parameter commonly used to assess in vivo dissolution and reflect bioavailability of drugs [31]. In this work, IDR was measured by the rotary basket method, which was applied to distinguish their dissolution properties. Prior to the IDR test, round discs of the samples should be compressed with a hydraulic press (Jintan Ruiding Machinery Co., Ltd. Changzhou, China). Specifically, 300 mg samples were compressed at a pressure of 115.2 MPa for 10 s to form smooth discs 8 mm in diameter. The acquired discs were coated with beeswax on three sides. The intrinsic dissolution study was performed at 100 rpm in 500 mL of hydrochloric acid buffer (pH 1.2) as a dissolution medium at 37 ◦C. The ARI concentration in solution was measured at the predetermined time interval by the same analysis method as the solubility test. The sink conditions were maintained during the entire dissolution experiment, and each test was performed in triplicate.
