Mikrosfere ropinirol hidroklorida za polagano oslobađanje: Utjecaj procesnih parametara

An emulsion solvent evaporation method was employed to prepare microspheres of ropinirole hydrochloride, a highly water soluble drug, by using ethylcellulose and PEG with the help of 32 full factorial design. The microspheres were made by incorporating the drug in a polar organic solvent, which was emulsified using liquid paraffin as an external oil phase. Effects of various process parameters such as viscosity of the external phase, selection of the internal phase, surfactant selection and selection of stirring speed were studied. Microspheres were evaluated for product yield, encapsulation efficiency and particle size. Various drug/ethylcellulose ratios and PEG concentrations were assayed. In vitro dissolution profiles showed that ethylcellulose microspheres were able to control release of the drug for a period of 12 h.Mikrosfere ropinirol hidroklorida, ljekovite tvari vrlo dobro topljive u vodi, pripravljene su metodom isparavanja otapala, koristeći etilcelulozu i PEG te 32 potpuno faktorijalno dizajniranje. Mikrosfere su pripravljene na sljedeći način: otopina ljekovite tvari u polarnom organskom otapalu emulgirana je s tekućim parafinom kao vanjskom uljnom fazom. Ispitivan je utjecaj različitih procesnih parametara poput viskoznosti vanjske faze, vrste interne faze i površinski aktivne tvari te brzine miješanja. Za pripravljene mikrosfere određeno je iskorištenje, učinkovitost inkapsuliranja i veličina čestica. Isprobavani su različiti odnosi ljekovite tvari i etilceluloze te koncentracija PEG-a. In vitro pokusi su pokazali da je oslobađanje ljekovite tvari kontrolirano tijekom 12 h

Effects of sphere size, polymer to drug ratio and plasticizer concentration on the release of theophylline from ethylcellulose microspheres

Theophylline sustained release microspheres were prepared by applying the non-solvent addition method. The in-vitro release of the drug from the prepared microspheres of different size ranges (≤300, 300-600, 600-800, 800-1000 and 1000-1250 μm) was studied. The effects of different ethylcellulose: theophylline ratios (1:2, 1:1 and 2:1) and different plasticizer (diethylphthalate) concentrations (10, 20 and 30% v/w) on theopylline release were also investigated. At different ethylcellulose: theophylline ratios (1:1, 2:1 and 1:2), the release of the drug decreased significantly when the polymer content was increased and the drug loading was decreased. Also, the release was significantly decreased (P<0.05) with increasing plasticizer concentration from 10 to 30%, with no significant difference between un-plasticized and 10 % plasticizerCorresponding Author: Dr. Ibrahim M. El-Bagory, Associate Professor Department of Pharmaceutics, College of pharmacy, PO Box 2457, Riyadh 11451, Saudi Arabia. Email: [email protected]