A novel mucoadhesive microcapsule with drug-resin complex core loaded with berberine hydrochloride (BH) was developed and optimized. Drug-ion exchange resin (IER) complex was prepared by static method which stirring IER in drug solution at certain conditions. The influences of different IERs, different temperature, pH values and concentrations of drug solution on the drug loading were investigated. IER complex was coated by emulsion-solvent evaporation method. The coating fluid formulation was optimized using central composite design-response surface methodology, where the ratio between Carbopol 934 and IER (X1), the ratio between Eudragit and IER (X2) and the ratio between Eudragit RL and RS (X3) were taken as independent variables. Time of cumulative release 85% (Y1) and percentage of gastric retention (Y2) were taken as response variables. Drug loading achieved a high level and more drug available in the condition of IER (IRP 88), 37 degrees C, pH 5 and 1.0 mg x mL(-1) drug solution. When X1 = 0.75, X2 = 0.9, X3 = 0.6, the time of cumulative release reached 85% at 300 min, the highest percentage of gastric retention in the range of this experiment were procured.
Acrylates ; chemistry ; Animals ; Berberine ; administration & dosage ; pharmacokinetics ; Capsules ; Delayed-Action Preparations ; Drug Compounding ; methods ; Drug Delivery Systems ; Emulsions ; Gastric Mucosa ; metabolism ; Hydrogen-Ion Concentration ; Ion Exchange Resins ; chemistry ; Male ; Polymers ; chemistry ; Rats ; Rats, Sprague-Dawley ; Temperature

Objective To explore the damage mechanism of dopamine cells induced by amphetamine (AMPH). Methods The damage model of dopaminergic cells in mice was established by intraperitoneal injection of AMPH. The mice were randomly grouped into control, saline, amphetamine treatment for 1 day, 7 days, 14 days and 28 days. Each group contained 10 mice. The model of cell injury was established by use of AMPH in PC12 cells. The dopaminergic fibers of corpus striatum and PC12 cells were observed by the immunohistochemistry and immunofluorescence method, and changes of proteins in the protein kinase B (Akt) / glycogen synthase kinase 3β(GSK-3β) / collapsin response mediator protein 2 (CRMP-2) signal pathway were detected by Western blotting. Results AMPH caused the damage of dopaminergic fibers in the mouse corpus striatum and PC12 cells. Meanwhile, AMPH inhibited Akt and GSK-3β phosphorylation levels, and increased phosphorylated CRMP-2 level. Nerve growth factor(NGF), an agonist of Akt, or SB216763, an inhibitor of GSK-3β protected PC12 cells against AMPH-induced toxicity through upregulation of Aat and GSK-3β phosphorylation and downregulated of phosphorylation CRMP-2. Conclusion AMPH causes damage of dopamine cells via inhibition of Akt/ GSK-3β/ CRMP-2 signal pathway.