Seemi Gul, Nargis Rehana Malik, Asima Malik, Nasim Akhtar, Iffat Ara, Majeeda Tahira.
Effect of innate lipid solubility on buccal absorption of basic drugs (Allopurinol hydrochloride, Nortriptyline hydrochloride and Procainamide hydrochloride) with similar pKa values.
Pak Postgrad Med J Jan ;18(2):51-5.
Objectives: Study is designed to find out the innate lipid solubility of buccal absorption of basic drugs with similar, pKa values. Allopurinol hydrochloride, Nortriptyline hydrochloride and Procainamide hydrochloride with pKa values 9.4, 9.2-9.7 and 9.2 respectively were selected for in vivo (Buccal absorption test) and in vitro Octanol/buffer partitioning coefficient) study at pH range 6-10. Results found that the mean percentage of bucc partitioning andl-octanol partitioning of allopurinol hydrochloride was decreased with the increase in pH from 6.0-10. Mean percentage of buccal partitioning andl-octanol partitioning of Procainamide hydrochloride and Nortriptyline hydrochloride was increased with the increase in pH from 6.0-10. It is concluded that although the drugs studied have nearly similar pKa values but their lipid solubility is varied widely. A good correlation between buccal and octanol partitioning excluded the possibility of interaction between these drugs and octanol. Decrease in lipid solubility of allopurinol hydrochloride needs further evaluation.
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