ABSTRACT
Objective Colon-targeting capsules based on gastric pellets and enteric pellets were prepared from Baizhu Huanglian prescription. The formulation composition and preparation process were optimized and the in-vitro release characteristics were investigated. Methods Optimum formulation composition and process parameters of Baizhu Huanglian pellets were screened out by single factor experiment and orthogonal design. The pellets core were prepared by extrusion-spheronization technique and coated in the fluid bed using bottom spray coating technique. To investigate the effect of coating level of the isolation layer, the proportion of polymer, the amount of plasticizer and weight gain of enteric coating on the release behavior of the enteric pellets. The pellets release behavior was fitted by model as well. Results The prescription of gastric pellets was drug loading 50%, PVPP 5%, MCC to lactose 1∶2 and wetting agent 40%. The process parameters were extrusion frequency 20 Hz, rounding speed 500 r/min and rounding time 5 min. The prescription of enteric pellets was drug loading 27%, PVPP 5%, MCC to lactose 5∶2, wetting agent 30% and adhesive 20%. The process parameters were extrusion frequency 20 Hz, rounding speed 700 r/min and rounding time 7 min. For enteric coating layer, the coating mixture of EUDRAGIT®L30D-55 to EUDRAGIT® FS30D was 1∶2. The amount of plasticizer was 10%. The increased weight of coating layer was 15%. The release time of enteric pellets in-vitro was up to 24 hours. The release behavior of the pellets conforms to the Higuchi model. Conclusion The colon targeting capsule of Baizhu Huanglian pellets were successfully prepared and showed the characteristics of sustained release and colon targeting.
ABSTRACT
Objective To synthesize a novel prostate cancer targeting gene vector PAMAM-PEG-C2min and improve gene transfection efficiency targeting on prostate cancer. Methods The aptamer (C2min) and polyamide-amine (PAMAM) were ligated by polyethylene glycol (PEG). The structure of the synthesized PAMAM-PEG-C2min was identified by NMR. The biological characteristics of the nanoparticles were examined by the uptake experiments and gene transfection experiments (the loaded gene was siR-M) with the prostate cancer cells (PC3 and LNCaP). Besides, the in vivo targeting was investigated using in vivo image system. The in vivo targeting results indicated that PAMAM-PEG-C2min can achieve the simultaneous targeting of two prostate cancer tissues. Results The PAMAM-PEG-C2min synthesis was confirmed by NMR. Cell uptake experiments showed that the cell uptake efficiency of PAMAM-PEG-C2min was concentration dependent. In vitro experiments showed that the PC3 and LNCaP cells transfection efficiency and targeting of PAMAM-PEG modified with C2min were significantly improved compared with the PEG modified PAMAM. Conclusion PAMAM-PEG-C2min is a potential targeted drug delivery vehicle. It provides a new technology platform for comprehensive and specific targeting treatment of prostate cancer.