Sodium carboxymethylcellulose as a coating polymer for spray-dried products

Abstract

Sodium carboxymethylcellulose in aqueous solutions was used as the coating polymer for the preparation of theophylline (model drug) aggregates using a spray-drying technique. The effects of sodium carboxymethylcellulose concentration, 0.4, 1, 2 and 3%, and ratio of drug/polymer, 1/4, 1/2, 1/1, 2/1 and 4/1, on the properties of spray-dried products were studied. The slowest drug release was observed for the spray-dried product with 1% sodium carboxymethylcellulose. These were also spherical and well-formed with improved flowability. A greater deviation of drug loading from the theoretical was observed with increasing proportion of drug in the drug/polymer ratio. The spray-dried product with drug/polymer ratio of 2/1 conforms to a biphasic first-order equation, and the other ratios conform to single-phase order and Higuchi square root of time equations.