Synthesis, hydrolysis kinetics and physicochemical properties of ester prodrugs of bucetin

Three amino acid esters and two alkyl esters of bucetin have been synthesized. The prepared esters possess different properties including aqueous solubility and lipophilicity. The non-enzymatic hydrolysis was studied in buffers of constant ionic strength at different pH values for the different compounds. The enzymatic hydrolysis in fresh rabbit plasma was studied for the two most promising compounds. Bucetin-4-morpholinoacetate and bucetin acetate revealed a reasonable hydrolysis pattern in plasma and could be considered the prodrugs of choice of bucetin in this study

Characterization of piroxicam-cyclodextrins inclusion complexes and their influence on ulcerogenic activity

Piroxicam was included into alpha- and beta-cyclodextrins crowns [1: 1 molar ratio] to give solid inclusion complexes. Solubility diagrams of piroxicam and cyclodextrins were presented. Spectroscopic analyses [UV and IR] as well as powder X-ray diffractometry were effective tools for further characterization of complexation. Certain physicochemical properties of these complexes [dissolution rate, permeation through cellophane membrane and apparent partition coefficient between organic and those of aqueous phases] were examined and compared with piroxicam alone. The rate of dissolution of piroxicam was significantly increased by the formation of inclusion complexes. The ulcerogenic activity of the drug was also significantly decreased upon complexation especially with beta- cyclodextrin

Design for rectal administration of verapamil hydrochloride

Verapamil hydrochloride, formulated in rectal suppository dosage from different suppository bases, were used. The permeation of the drug through standard cellophane membrane and its dissolution in aqueous medium from the different formulations were performed at 37C. The water soluble base, polyethylene glycol showed the highest release of the drug. The drug release characteristics indicated adherence to first order kinetics mechanism. In vivo rabbit studies of two suppository formulations compared with intravenous and oral doses were performed. The rectal administration of verapamil hydrochloride in suppositories resulted in a more rapid onset and more intense depressor responses than the oral route