Speciaton

To answer this question:

Diclofenac (brand name Voltaren) is a non-steroidal anti-inflammatory agent that is used to treat pain and inflammatory diseases such as gout.

The chemical structure for the acid form of Diclofenac is shown below.

(a) Draw the structure of the conjugate base of Diclofenac. (1 mark)

Shown below is the speciation of Diclofenac as a function of pH.

(b) What is the pK_a for Diclofenac? Justify your answer.

(c) The pH of the stomach is 1.5. What is the ratio of acid to base in the stomach?

(d) The pH of the small intestine is 7.5. Would Diclofenac be absorbed more readily from the stomach or the small intestine? Explain your answer, making reference to the speciation.

BRIEFLY PLEASE

CI NH CI Acidic Hydrogen O Speciation Plot for Diclofenac 1 0.9 0.8 0.7 conjugate base acid Fraction 0.6 0.5 0.4 0.3 0.2 0.1 0 0 1 2 3 4 5 8 9 10 11 12 13 14 PH