Binary Solid Dispersions of Telmisartan using natural modified Neem Gum: Development and Characterization

Abstract

Current study investigates dissolution enhancement of poorly soluble antihypertensive drug telmisartan using neem gum as a carrier. Telmisartan is a BCS Class II drug i.e. it has poor solubility and high permeability. Various mixtures of Telmisartan using neem gum were prepared. 4 batches of solid dispersions SD (SD1, SD2, SD3, SD4) were prepared by solvent evaporation method and evaluated for equilibrium solubility studies. Solubility studies indicated 1:3 ratio as the best one from solid dispersion. Significant improvement was observed in SD3 batch in vitro dissolution studies. Further, other mixtures were prepared in 1:3 ratio using different methods (Physical Mixing, Kneading Method, Swollen Mixture, Co-grinding Method). Out of various mixtures, Kneading mixture exhibited significant improvement in drug dissolution which is equivalent to that of SD3. FTIR, DSC, X-RD, SEM studies and in vitro dissolution were done of all the mixtures. FTIR studies indicated no interaction of drug to polymer (neem gum), DSC, XRD and SEM studies indicated transition from crystalline to amorphous state of drug. SD3 powder was compressed into fast dissolving tablet dosage form. The disintegration and wetting time was observed to be less than I min. SD3 tablet batch also exhibited significant enhancement in in vitro dissolution (100% drug release in 60 min). The tablet batch was found to be stable for 3 months under accelerated condition of temperature and humidity. Therefore, neem gum can be used as a natural carrier for better dissolution of poorly soluble drug telmisartan.