Valdisoval (VL) is a mixture of sodium valproate (SV) and valproic acid (VA) in a 2:1 ratio. Different polymers were used to develop a controlled-release tablet formulation for VL using either direct compression or wet granulation techniques. Eudragits RSPO and RLPO in different concentrations were used as direct compression and rate controlling polymers, while ethyl cellulose (EC), hydroxy propyl methyl cellulose (HPMC) and hydroxy ethyl cellulose (HEC) were used as release retardants in the wet granulation matrix formulations. Tablets prepared showed good physical properties; e.g. hardness, friability, weight variations, using different polymers by direct compression and wet granulation techniques. The release profile of SV from the compressed tablets was studied using the USP dissolution apparatus II at 100 rpm in either distilled water for 8 hours or in 0.1 N HCl for one hour followed by phosphate buffer, pH 6.8 for another 7 hours. Sodium valproate release was found to decrease by increasing the concentration of Eudragit RSPO in the formula and was less affected by the concentration of Eudragit RLPO.The release of SV from the tablets containing ethyl cellulose as tablet matrix was affected by the type of the binder in the wet granulation process. This was indicated by the difference in T50% (time for 50% of the drug to be released). HEC was used as a release retardant in a concentration range 10 to 25% w/w. The release of SV from these tablets was inversely proportional to HEC concentration in the formula.Tablets containing 12.5% w/w of this polymer were film coated using Eudragit L100-55.When the release profile of SV from these tablets was compared to a marketed product (Depakine ChronoR) under the same conditions, an almost identical dissolution pattern was found. Zero order release kinetics was elucidated from the dissolution data.
)
View on SCiNiTO