Subcoating with Kollidon VA 64 as water barrier in a new combined native dextran/HPMC-cetyl alcohol controlled release tablet.

A novel oral controlled delivery system for propranolol hydrochloride (PPL) was developed and optimized using wet granulation process. We are studying the ability of subcoating with Kollidon VA 64 as a barrier to water penetration in matrix cores combined hydrophilic (native dextran-HPMC)/hydrophobic (cetyl alcohol) prior to film coating with Opradry II-YS-30-18056. The copovidone (i.e., Kollidon VA 64) not only increases the mechanical properties of tablets (less friability) but also reduces the amount of absorbed water from the air in tropical stability condition (25 degrees C and 75% relative humidity). The in vitro dissolution profiles of coated sustained-release matrix tablets of racemic PPL were determined and compared with uncoated tablet cores according to the United States Pharmacopeia (USP) Tolerance Specifications for Propranolol Hydrochloride Extended-Release Capsules. A comparative kinetic study of the present matrix tablets (coated and uncoated cores) and commercial SUMIAL RETARD capsules (reference formulation (R) (Spain) was established). The values for the similarity factor (f2=61.756, f2=72.326 and f2=88.509 for initial time, one year and two years, respectively (uncoated cores vs. capsule) and f2=63.904, f2=69.502 and f2=76.348 (coated tablets vs. capsule) for initial time, one year and 2 two years, respectively) suggested that the dissolution profiles of the present three sustained-release oral dosage forms are similar and stable during two years under stability condition.