Influence of pH on the buccal absorption of morphine sulphate and its major metabolite, morphine‐3‐glucuronide

Abstract

Buccal absorption of morphine sulphate and morphine‐3‐glucuronide at various buffer pH values (4 to 10) over 5 min has been investigated in seven and four normal healthy volunteers, respectively. Increasing pH caused an increase in buccal absorption of both. The maximum mean absorption was 37% at pH 10 for morphine and 19% at pH 8 for morphine‐3‐glucuronide. 1987 Royal Pharmaceutical Society of Great Britain