This study was to design and evaluate effervescent floating tablets with sustained release behaviour. Pentoxifylline is a water-soluble model drug with a short half-life, consequently developing sustained release preparations would be beneficial.
A binary (1:1) mixture of sodium alginate and hydroxyethyl cellulose containing pentoxifylline, with either 10% or 20% calcium carbonate or sodium carbonate, was used to prepare floating tablets.
Tablets floated on the surface of the dissolution medium, showed an adequate floating lag time, and floated for more than 12 hours. Tablets manufactured from granules with 20%(w/w) calcium carbonate were promising with respect to their floating lag time (~ 7min), floating duration (> 24 hours), sustained drug release rate, and swelling ability. An in vivo study of these promising tablets and a reference solution of pentoxifylline were investigated following oral administration of 5.75 ± 0.15mg in rats. Compared with the reference solution, the pharmacokinetic parameters changed significantly (p < 0.05); the Cmax of the tablets was decreased (945.32ng/ml versus 2552.30ng/ml for the solution), while the Tmax and t1/2 were prolonged.
The study shows that a binary mixture of hydroxyethyl cellulose and sodium alginate, together with 20%(w/w) calcium carbonate, offers an exciting opportunity to develop sustained release pentoxifylline preparations.