Fresh okra pods were purchased from local market and were
frozen and kept at 20 C until handling. Flurbiprofen (FBP) and
theophylline (THP) were purchased from Aesica Pharmaceuticals
Ltd (Cramlington, UK) and Tokyo Chemical Industry Ltd (UK),
respectively. Citric acid monohydrate, sodium citrate dehydrate
were used for citric buffer preparation, sodium azide was used as a
preservative and n-hexadecane as dispersed phase for o/w emulsions.
All reagents were obtained from SigmaeAldrich (UK). Disodium
hydrogen phosphate (Na2HPO4) and sodium dihydrogen
phosphate (NaH2PO4) were purchased from Fisher Scientific, (UK).
All reagents used were analytical grade.