Spray-Dried Powders of Casein-Encapsulated Rutin Stabilized With Sugars for the Enhancement of Intestinal Drug Solubility.

Numerous therapeutic potentials of rutin (RUT) including cardioprotective, neuroprotective, and antihypertension activities have attracted many studies to bring it into clinical use. RUT is phytochemically derived from plants such as apples and tea. It is poorly soluble and very sensible to acidic pH in the stomach environment which leads to conceded oral bioavailability. In contrast, RUT is better soluble in basic environment, thus, encapsulating RUT within enteric microparticles (RUT-MP) using casein (CAS) resolved such problems. The encapsulation by spray-drying employed sugars (lactose, sucrose, and maltodextrin) as bulking agents and for stabilization of the amorphous drug. The developed RUT-MP formulations were prepared in two groups i.e., lower and higher RUT concentrations. The solid states were studied by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). Solubility tests were also carried out on the samples to examine the outcome of the engineered physical modification. The results showed that the RUT-MPs were spherical in morphology. The RUT was transformed into amorphous structure as suggested by the XRD and DTA results indicating that RUT was molecularly dispersed in the RUT-MP. There were no phase separations that occurred as confirmed by the DTA data. Solubility tests carried out on the RUT-MPs showed that the encapsulation with CAS in group with higher concentration of RUT prevented the drug against recovery of the crystallinity and phase separations. The solubility test revealed various substantial enhancements of RUT solubility of the RUT-MPs at pH 7.0. The highest enhancement of RUT solubility was 191,5-fold, with respect to pure RUT. The presence of sugars was beneficial as they improved the yield percentage and might have contributed to the prevention of nano-crystal aggregation which made them a determining aspect for the successful application of spray-dried encapsulation.