Abstract
Hydroalcoholic solutions of hydroxypropyl methylcellulose (HPMC) can be used in place of gelatin solutions to seal pharmaceutical capsules. The control of HPMC concentration is essential to ensure a complete, uniform, and stable capsule seal. Sealing solution concentration is usually monitored by measuring the solution viscosity through a viscometer. HPMC solutions, however, are pseudoplastic rather than Newtonian fluids, thus their viscosity depends not only on the solution concentration, but also on the shear rate applied during stirring and/or transfer of solution from one container to another. The authors demonstrate that a proper measure of HPMC solution concentration is its electrical conductivity rather than its viscosity. The correlation between concentration and conductivity was tested in the concentration range 12-25% and a mathematical expression was proposed for it. This correlation allows one to control and adjust the solution water/alcohol ratio using a conductivity measurement.
| Original language | Undefined/Unknown |
|---|---|
| Pages (from-to) | 46-52 |
| Number of pages | 7 |
| Journal | Pharmaceutical Technology |
| Volume | 41 |
| Issue number | 10 |
| Publication status | Published - 2 Oct 2017 |
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