Effect Of Hydrophilic Polymers On Dissolution Rate Of Roxithromycin
In the present investigation, the enhancement of dissolution rate of roxithromycin was carried out by preparing solid dispersions using hydrophilic polymers like polyethylene glycol 6000, hydroxypropylmethylcellulose K4M and hydroxypropylcellulose, each in the ratios of 1:1, 1:3 and 1:5. Physical mixing and coprecipitate techniques were employed to prepare formulations for increasing the solubility of roxithromycin. Formulations prepared by both physical mixing and coprecipitate methods have shown significant enhancement of dissolution rates compared to pure roxithromycin alone. All the solid dispersions obtained were fine and having good flow properties. The formulation, polyethylene glycol 6000:CP5 containing roxithromycin:polyethylene glycol 6000 in 1:5 ratio has shown 99.4% drug release in 1h. The dissolution rate of roxithromycin was directly proportional to the increment in the drug to polymer ratios in the solid dispersions. Dispersions prepared by coprecipitate method have shown faster dissolution rate compared to physical mixing techniques. The dissolution efficiency of the formulation polyethylene glycol 6000:CP5 was found to be highest compared to other formulations. The release profiles of roxithromycin from the dispersions have followed first order release kinetics and Hixson-Crowell's cube root law. It was concluded that hydrophilic polymers can be employed to prepare solid dispersions to enhance the solubility of roxithromycin.