Química Nova (Jan 2013)

Contextualizando reações ácido-base de acordo com a teoria protônica de Brönsted-Lowry usando comprimidos de propranolol e nimesulida

  • Arlan de Assis Gonsalves,
  • Cleônia Roberta Melo Araújo,
  • Carlos Alberto Leite Filho,
  • Felipe Santana de Medeiros

DOI
https://doi.org/10.1590/s0100-40422013000800024
Journal volume & issue
Vol. 36, no. 8
pp. 1236 – 1241

Abstract

Read online

This paper reports the use of alternative materials for teaching experimental chemistry. In this context, nimesulide and propranolol tablets were used to teach chemical concepts about acid-base reactions according to Brönsted-Lowry protonic Theory. Important topics of Organic, Analytical and Pharmaceutical Chemistry were discussed, such as purification by acid-base extraction, solubility of organic compounds in aqueous solutions, buffers, the dissociation constant (pKa), potentiometric titration and ionization of drugs in biological fluids. The purification of propranolol and nimesulide from tablets produced yields of 75% and 90%, respectively. The experimental values of pKa for both drugs were in agreement with those from the literature.

Keywords