HPMC empty capsules still have following unique properties:
• Low moisture content.HPMC capsules contains 60% less moisture than gelatin capsules . well suited for moisture sensitive drugs , capsuels have a low moisture content level.(5%-6% at 50% R.H.) and will not retain elevated moisture levels after exposure to highly humid conditions .
•No risk of capsules cross linking.
To assess cross-linking effect Veg capsules were pre-filled with dillient containing 40 ppm of formaldehyde (a known cross –linking agent ) and stored for three months. These test capsules were then emptied and re-filled with acetaminophen and tested according to the USP monograph , Test results indicated that the dissolution of the test capsules matched those not exposed to formaldehyde .
