Effect of some additives on the properties of phenazopyridine hydrochloride granules and their corresponding tablets.

The effect of the diluents, lactose and calcium carbonate and of the binders, syrup, gelatin, methylcellulose and Eudragit E on the physical properties of phenazopyridine hydrochloride (PNHCl) granules was evaluated. A correlation existed between the granules' physical properties and those of their compressed tablets. With regard to drug release, lactose-syrup 30% was the best of all diluent-binder combinations, followed by lactose-methylcellulose 4%. Also lactose was found to be superior to calcium carbonate in drug release when gelatin and methylcellulose were used as binders. Eudragit E was the best binder with calcium carbonate in this respect. On the other hand, the bioavailability of PNHCl in humans was the same when lactose was used with either gelatin, syrup or methylcellulose, but higher than that obtained with a combination of calcium carbonate and Eudragit E 15%.