OPTIMIZATION OF RHAMNOGALACTURONAN EXTRACTION FROM LINSEED USING RSM AND DESIGNING A pH-RESPONSIVE TABLET FORMULATION FOR SUSTAINED RELEASE OF CIPROFLOXACIN ANTIBIOTICS

Herein, we reported the optimization of the isolation parameters to obtain the maximum yield of the linseed mucilage (LSM) through a statistical technique, i.e., response surface methodology by applying Box-Behnken Design (RSM-BBD). The aqueous isolation yield of LSM was optimized by studying the influence of temperature (T, °C), pH, seed-to-water contact time (t, h), and seed-to-water ratio (r, w/v). The maximum yield of LSM, i.e., 12.89%, was found at T of 71.9 °C, pH of 7.09, t of 6.24 h, and r of 1:24.50 w/v, according to RSM-BBD. The pH-responsive swelling of the LSM-based tablet formulation (M3), in buffers of pH 1.2, 6.8, and 7.4, and the swelling-deswelling (on-off switching) profile of M3 in the buffers of pH 7.4 and 1.2, respectively, were investigated. The results revealed that formulation M3 swelled at pH 6.8 and 7.4, but expressed minor swelling at pH 1.2. Moreover, formulation M3 showed swelling-deswelling behavior at pH 7.4 and 1.2, respectively. The LSM sustained the release of ciprofloxacin for 24 h and followed the first-order release kinetics as well as a non-Fickian diffusion mechanism. Concluding, the LSM can be considered as a pH-responsive sustained drug rele