A preliminary study of the effect of slug hardness on dissolution from hard gelatin capsules filled on an automatic capsule-filling machine

Abstract

The effect of magnesium stearate on slug hardness and the dissolution of hydrochlorothiazide from hard gelatin capsules filled on an instrumented Zanasi automatic capsule-filling machine at constant compression force is reported. The fillers were microcrystalline cellulose and anhydrous lactose. Slug hardness was assessed by measuring the breaking load of slugs in a three-point bending test. With microcrysallire cellulose, t60% first decreases to a minimum and then increases with increased lubricant levds, confirming the findings of Stewart et al. (1979). This is accompanied by a dramatic decrease in slug hardness. With lactose, t60% increases with the lubricant level white slug hardness decreases slightly, although not significantly (5% level) at the levels tested. With microaystalline cellulose, it is proposed that the increased hydrophobtcity of the slug with increasing lubricant levels initially is more than offset by reduced slug hardness which probably enhances deaggregation and wetting of capsule contents. © 1981.