title: Analysis of moisture sorption hysteresis in hard gelatin capsules, maize starch, and maize starch: drug powder mixtures.
abstract: Moisture sorption and desorption isotherms at 25 degrees C for hard gelatin capsules, maize starch and 50:50 mixes of maize starch: barbitone and maize starch: sodium barbitone have been measured. The sorption hysteresis observed in all four systems studied has been analysed according to the hypothesis of Young & Nelson (1967a) which distinguishes three locations for moisture--monolayer adsorbed moisture, normally condensed moisture and absorbed moisture. Hysteresis is explained by a separation of absorption and desorption isotherms for absorbed moisture and different patterns of moisture distribution are demonstrated in the four systems examined.
mesh_terms: D000327:Adsorption; D002214:Capsules / Q000032:analysis; D005780:Gelatin; D011208:Powders / Q000032:analysis; D013213:Starch / Q000032:analysis; D014867:Water / Q000032:analysis
chemical_list: D002214:Capsules; D011208:Powders; D014867:Water; D005780:Gelatin; D013213:Starch