The shell dissolution of various empty hard capsules

The shell dissolution properties of gelatine, gelatine/polyethylene glycol (PEG) and hydroxypropyl methylcellulose (HPMC) capsules were studied as a f unction of temperature, dissolution medium, and after different storage con ditions. In any dissolution medium with a pH below or equal to 5.8, HPMC ca psule shells dissolved rapidly: and there was no difference in the time in which dissolution occurred in the tested temperature interval of 10 to 55 d egrees C. Gelatine and gelatine/PEG capsule shells, generally did not disso lve at temperatures below 30 degrees C. The shell dissolution time of all c apsules tested was prolonged and more variable in mixed phosphate buffer pH =6.8. The addition of enzymes (pepsin, pancreatin) to any dissolution mediu m was found not to enhance the differences between the different types of c apsules investigated. In practical terms, the results indicated that capsul e formulations should not be taken with drinks from the carbonated Cola-typ e. Gelatine containing capsules should preferably be administered with a wa rm drink, whereas HPMC capsules could be given with cold or warm drinks. Th e latter type of capsules should also be preferred for preparations to be t aken in the fasted state. A short storage of gelatine containing capsules u nder hot humid tropical conditions appeared not to alter the dissolution pr operties of the shells, and changes in disintegration times and dissolution times of formulations filled in such capsules might be a reflection of cha nges of the powders incorporated rather than of the capsule shells. However , a short storage of HPMC capsules under such conditions appeared to influe nce the capsule shell matrix.