Bu araştırmanın amacı, emülsiyon çözücü buharlaştırma kullanarak hazırlanan Eudragit (Eud) RL ve RS mikro küreleri ile günde bir ve iki kez uygulama için diltiazem hidroklorürün (DL) uzatılmış salım formülasyonunu geliştirmektir. Gereç ve Yöntemler: Farklı etken madde-polimer konsantrasyonlarına sahip formülasyonlar üretilmiş ve verim, enkapsülasyon etkinliği (EE), partikül büyüklüğü ve yüzey morfolojisi açısından karakterize edilmiştir. Mikrokürelerin etken madde salınımı ve termal davranışı da incelenmiştir. Seçilen mikro küreler daha sonra mikro kürelerin özelliklerini modifiye ve hızlı ilk salınımını değiştirmek için sürekli çözücü buharlaştırma yoluyla Eud RS ile kaplanmıştır. Bulgular: Sonuçlara göre, kaplanmamış mikroküreler için EE %56-%93 aralığındadır. Mikrokürelerin ortalama partikül büyüklüğü, çeşitli formülasyon değişkenlerine bağlı olarak 470 ila 1000 um'nin üzerinde olmuştur. Eud RL ve Eud RS ile hazırlanan partiküllerin ortalama ortalama partikül büyüklüğü arasında bir fark gözlenmemiştir. Mikroküreler, etken madde: polimer oranının yanı sıra partikül boyutundan etkilenen sürekli salım davranışı göstermiştir. Mikrokürelerin kaplanması sadece EE değerlerini iyileştirmemiş (%82-%92), aynı zamanda hızlı ilk çıkış yanı sıra ortalama çözünme oranınıda (MDR) azaltmıştır. Objectives: The aim of this investigation was to develop an extended release formulation of diltiazem hydrochloride (DL) for once-and twice-daily administration, based on Eudragit (Eud) RL and RS microspheres using emulsion solvent evaporation. Materials and Methods: Formulations with different drug-polymer concentrations were produced and characterized in terms of yield, encapsulation efficiency (EE), particle size, and surface morphology. The drug release and thermal behavior of the microspheres were also investigated. Selected microspheres were then coated with Eud RS by continuous solvent evaporation, in order to modify the microspheres' properties and burst release. Results: According to the results, the EE was in the range of 56%-93% for uncoated microspheres. The mean particle size of microspheres was different from 470 to above 1000 µm, based on various formulation variables. No difference was observed between the mean size of particles prepared with Eud RL and Eud RS. Microspheres showed sustained release behavior, which was affected by the drug:polymer ratio as well as particle size. Coating the microspheres not only improved the EE values (82%-92%) but also reduced the mean dissolution rate as well as the burst release. Conclusion: Microspheres prepared with DL:Eud RL ratios of 1:3 and 1:4 showed release profiles in accordance with the USP criteria for a DL extended release product for dosing every 12 and 24 h, respectively.

The aim of this investigation was to develop an extended release formulation of diltiazem hydrochloride (DL) for once and twice-daily administration, based on Eudragit (Eud) RL and RS microspheres using emulsion solvent evaporation method. Methods: Formulations with different drug-polymer concentrations were produced and characterized in terms of yield, encapsulation efficiency (EE), particle size and surface morphology. The drug release and thermal behavior of microspheres were also investigated. Selected microspheres were then coated with Eud RS by continuous solvent evaporation method, in order to modify the microspheres properties and burst release. Results: According to the results, the EE was in the range of 56-93 % for uncoated microspheres. The mean particle size of microspheres was different from 470 to above 1000 µm, based on various formulation variables. No difference was observed between the mean size of particles prepared with Eud RL and Eud RS. Microspheres showed sustained release behavior which was affected by drug: polymer ratio as well as particle size. Coating the microspheres not only improved the EE values (82-92 %), but also reduced the mean dissolution rate (MDR) and also the burst release. Conclusion: Microspheres prepared with DL: Eud RL ratios of 1:3 and 1:4, showed the release profiles in accordance with the USP criteria for DL extended release product, for dosing every 12 and 24 h, respectively.