Effect Of Acetylation And Route Of Administration On The Absorption Of Sulphaphenazole And Sulphacetamide Sodium In Rabbits

Abstract

This investigation determined the effect of varying route of drug administration on the rate and extent of absorption of sulphacetamide sodium and sulphaphenazole in 4 rabbits. The N -acetyl derivatives of both sulphacetamide and sulphaphenazole were also administered as follows;- (i) acetyl sulphacetamide was administered both orally and intravenously. (ii) acetyl sulphaphenazole was administered orally„ Unconjugated sulphaphenazole was also administered orally for comparison. The aim of administering the acetylated sulphonamides was to establish the possible effects of acetylation on the absorption of both sulphacetamide and sulphaphenazole. Five different routes of administration were investigated namely oral, intravenous, subcutaneous, intramuscular and intraperitoneal routes. The plasma clearance of sulphacetamide was determined and compared with that of acetyl sulphacetamide. This was done by administering equivalent doses of sulphacetamide and its acetyl derivative to different rabbits. Blood samples were obtained at predetermined times after drug administration and analysed for both sulphacetamide and acetyl sulphacetamide. The bioavailability of sulphaphenazole when administered orally was compared to that of its acetyl derivative basing the comparison on the level of sulphaphenazole attained in plasma with time after drug administration. Results of this investigation showed that, The absorption rate of sulphacetamide sodium was in the order iv> ip > im >sc >oral route. It was also established that sulphacetamide has a higher plasma clearance than its acetyl derivative and that acetylation retarded the absorption of sulphaphenazole. Similarly, it was evident that orally administered sulphaphenazole produces high and stable plasma concentration of the drug such that the dosing frequency is not as high as for other sulphonamides. It is therefore a long acting sulphonamide.