In an attempt to reduce the gastrointestinal side effects of aspirin, zinc aspirin complex
was prepared and formulated into suppositories. The prepared suppositories were evaluated invitro
for their hardness, melting range, uniformity of weight and drug content and in-vivo drug
release.
The pharmacokinetic and pharmacodynamic properties of zinc aspirin were evaluated in
comparison with that of aspirin and aspirin lysinate (aspegic) following rectal and oral
administration in experimental animals. Blood samples were collected at different time intervals
after adminstration of drugs under evaluation. Salicylic acid (main metabolite of aspirin) was
determined in plasma by using high performance liquid chromatography (HPLC). The antiinflammatory
activity was studied in albino rats using carrageenan oedema model; and the
analgesic activity was studied using hot plate and writhing methods.
The results revealed that following rectal administration, the bioavailability of zinc aspirin
was significantly (P<0.05) greater than that of aspirin and aspirin Lysinate. The absolute bioavailabilities were 94, 88.89 and 83.63 for zinc aspirin; aspirin lysinate and aspirin
respectively. The peak plasma concentration (Cmax) were 54.5188, 50.271.68 and 48.091.15
ugl-1 for zinc aspirin, aspirin lysinate and aspirin, respectively. There was significant difference
in the tmax. The area under the plasma concentration-time curve (AUC) values were
148.932.79, 140.832.3 and 132.493.56 ug.h/ml for zinc aspirin, aspirin lysinate and
aspirin, respectively. There were significant differences in the Cmax, tmax and AUC following oral
administration. The anti-inflammatory and analgesic studies revealed that zinc aspirin
administered rectally or orally was more effective as anti-inflammatory and analgesic. The invivo
studies were correlated with the in-vitro release studies of aspirin from the prepared
suppositories.
Based on the obtained results, the authors recommend the possible use of zinc aspirin as a
substitute of aspirin containing products.