ABSTRACT
The multiple drug delivery system of components of traditional Chinese medicine is a system composed of multiple components and multiple units. According to the characteristics of each component, different drug delivery units are designed and combined to achieve the purpose of improving bioavailability and enhancing drug efficacy. In this study, supercritical extracts, phenolic acids, and polysaccharides derived from Angelica sinensis were examined as research objects, and a pellet-based vehicle was applied to construct a multiple drug delivery system for the treatment and chemoprevention of colitis and colorectal cancer. The extrusion-spheronization method was used to prepare pellets of Angelica polysaccharides which should be released in the stomach. The yield in 18-24 mesh and plane critical angle served as the index. The Box-Behnken design and the orthogonal design were used to optimize the formulation and parameters of pellets. According to a previous study, the colon specific pellets loading supercritical extracts and phenolic acid extracts were prepared by the optimized process. These two units of pellets were combined into the multiple drug delivery system of effective components of Angelica sinensis, and the quality evaluation and in vitro release study were conducted. The dynamic observation of pellets in mice was evaluated using small animal in vivo imaging system. The prescription of the Angelica polysaccharides gastric releasing pellets was:microcrystalline cellulose 6.5 g, polysaccharide 3.3 g, silica 0.2 g and 7 mL of 60% ethanol as wetting agent. The process parameters were as follows:extrusion rate at 75 r·min-1, rounding rate at 1 800 r·min-1, and rounding time for 3 min. Both in vivo and in vitro studies indicate that the prepared multiple drug delivery system of effective components of Angelica sinensis produced good release properties. The polysaccharide pellets could be rapidly released in the artificial gastric fluid and in the stomach. The colon specific pellets showed good targeting. They released little in the artificial gastric fluid within 2 hours, released less than 20% in the artificial intestinal fluid for 4 hours, and released more than 90% in artificial colon fluid for 6 hours.
ABSTRACT
Gastric adhesive-floating pellets for Bolo leaf phenols (BLP) were prepared by extrusion-spheronization method, with chitosan as skeleton bioadhesive material, and stearyl alcohol as help-bleaching agent to evaluate its in vitro adhesivity, floatability and in vivo retention situation, and investigate its in vitro release characteristics. The in vitro adhesivity and floatability were evaluated respectively by in vitro tissue retention method and visual observation method. The retention of pellets in rats was investigated by in vivo tissue retention method and in vivo imaging of small animals. In addition, the in vitro release of p-coumaric acid and caffeic acid as the index components in pellets were evaluated. Results showed that the in vitro adhesivity of the prepared gastric adhesive-floating pellets reached (73.2±3.4)%, and the pellets could float immediately in simulated gastric fluid for more than 12 h; the retention rate of adhesive-floating pellets in rats reached more than 40% after 6 h, while the retention rate of common reference pellets was decreased by 15% as compared with the gastric adhesive-floating pellets, with significant difference (P<0.01); the drug in vitro release time can reach more than 6 h, and the drug release behaviors were lined with Higuchi equation. In vivo and in vitro studies showed that, the gastrointestinal bioadhesive and floating pellets prepared in this study have good bioadhesivity, floatability and good sustained release characteristics.