Romanian Society of Pharmaceutical Sciences

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KINETIC ANALYSIS OF IN VITRO DRUG RELEASE FROM VALPROIC ACID AND SODIUM VALPROATE SUPPOSITORIES

ADRIANA CIURBA1, NICOLETA TODORAN1*, ALEXANDRINA TĂUREAN2, PAULA ANTONOAEA1, GABRIEL HANCU3, ANCA MOISEI4, EMESE SIPOS5

1.University of Medicine and Pharmacy of Tîrgu Mureş, Romania, Faculty of Pharmacy, Department of Pharmaceutical Technology
2.University of Medicine and Pharmacy of Tîrgu Mureş, Romania, Faculty of Pharmacy, Pharmacy no. 3, County Emergency Hospital, Tîrgu Mures
3.University of Medicine and Pharmacy of Tîrgu Mureş, Romania, Faculty of Pharmacy, Department of Pharmaceutical Chemistry
4.“Lucian Blaga” University, Sibiu, Faculty of Medicine
5.University of Medicine and Pharmacy of Tîrgu Mureş, Romania, Faculty of Pharmacy, Department of Pharmaceutical Industry and Biotechnology

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The present study aims to develop new formulations of suppositories containing valproic acid or sodium valproate for the pediatric use of anticonvulsant therapy. Seven formulations of valproic acid suppositories have been proposed with four lipophilic excipients (Suppocire® NAI25, Witepsol® W35, Massa Estarinum E299, Lipex® 403) and three hydrophilic bases with polyethylene glycol in various ratios (PEG1600 and PEG4000). The four above-mentioned lipophilic excipients were used to prepare the sodium valproate suppositories, either in the presence of 5% cetyl alcohol, or of 3% Solutol® HS15, resulting in 8 liposoluble formulations. Three water-soluble formulations were also made using PEG basis. The eighteen proposed formulations were studied over a period of 8 hours in terms of in vitro drug release and diffusion through synthetic membrane. The release kinetics were evaluated both by independent and time-dependent methods. Akaike Information Criterion (AIC), used as discrimination criterion, indicated that the most suitable models to describe kinetics of drug release from the 18 analysed suppository formulations are the Hopfenberg with Tlag model and the Peppas-Sahlin-2 model.