Formulation and Evaluation of Solid Dispersion by Novel Technique

Hot melt extrusion (HME) is the most widely applied processing techniques, with its several advantages including enhancement of the dissolution rate and bioavailability, controlling or modifying drug release, taste masking, stabilizing the active pharmaceutical ingredient (API). Hot Melt Extruded dosage forms are complex mixtures of API, plastisizers and polymer carriersin which the molten thermoplastic polymers during the extrusion process can function as thermal binders and/or release retardants. Present investigation deals with enhancement of dissolution rate and hence solubility of Dapsone (Dap). Dap is a primary used for treatment of Dermatitis herpetiformis, as an antibacterial drug for susceptible cases of leprosy with long half life of 52-56 hrs. Solubility enhancement techniques are available in wide range but HME was the preferred technique due to its several advantages. Copovidone (Kollidon VA64) as polymer and polyethylene glycol (PEG 4000), polyoxy 35 castor oil (Cremophor EL) and sorbiton monolaurate (Montane 20 PHA) as plasticizers were studied and optimized. Evaluation techniques like saturation solubility, effect of temperature on preparation of complexes, differential scanning calorimetry (DSC), x-ray diffraction (XRD), Infra red (IR), dissolution and in vitro permeability studies were carried out. Results concluded enhanced dissolution and solubility. Stability studies at 40°C/75 % RH (relative humidity) showed that the sample is stable even after 3 months study. HME is simple and efficient method to improve dissolution and permeability of poorly water soluble Dap.