Impact of release characteristics of sinomenine hydrochloride dosage forms on its pharmacokinetics in beagle dogs

Figure 1 Effect of different coating levels on SM·HCl release behavior from the coated pellets in distilled water (n = 6). A: Pellets coated at five levels of 0% (◇), 3% (□), 5% (△), 6.5% (○), 8% (●, w/w, total solid applied); B: rapid-release pellets (▲) and slow-release pellets at a 6.5% coating level (△) and a mixture of slow- and rapid-release pellets (9:1, w/w, ●).

Figure 2 Effect of pH of the dissolution medium on SM•HCl release from coated pellets of the optimal formulation (n = 6). Distilled water (○), 0.1 mol/L HCl (●), pH 6.8 (△) and pH 7.4 (□) PBS.

Figure 3 Comparative SM•HCl release profiles of 24-h test sustained-release pellets (●) and 12-h reference sustained-release tablets (○, n = 6).

Figure 4 SM•HCl plasma concentration-time profiles after oral administration of 24-h test sustained-release pellets (●) and 12-h reference sustained-release tablets (○) in beagle dogs at a single dose of 120 mg/animal. Each value represents mean±SE (n = 6).

Figure 5 Relationship between cumulative SM•HCl percentage release in vitro f(t) and percentage absorption in vivo F(t) of the two dosage forms. S, I and R are the abbreviations for the slope, intercept and correlation coefficient for the correlation equation, respectively. Twenty-four-hour test sustained-release pellets (●) and 12-h reference sustained-release tablets (○).