Application of spray granulation for conversion of mixed phospholipid-bile salt micelles to dry powder form: influence of drug hydrophobicity on nanoparticle reagglomeration

Abstract

Qingyuan Lv,1 Xianyi Li,2 Baode Shen,1 He Xu,1 Chengying Shen,1 Ling Dai,1 Jinxia Bai,1 Hailong Yuan,1 Jin Han11Department of Pharmacy, 302 Military Hospital, 2Institute for Drug and Instrument Control, Health Department, General Logistics Department of People's Liberation Army, Beijing, People's Republic of ChinaAbstract: The aim of this study was to investigate the feasibility of using spray granulation as a drying method to convert phospholipid (PL)-sodium deoxycholate (SDC)-mixed micelles (MMs) containing a water-insoluble drug to a solid dosage form and to evaluate how drugs with significantly different physicochemical properties affect the spray granulation process and subsequent in vitro and in vivo processes. Cucurbitacin B (Cu B) and glycyrrhizin (GL) were used as the model drugs. After spray granulation, the dried Cu B-PL/SDC-MM powder was completely redispersible within 15 minutes in vitro. Meanwhile, the area under the curve during 24 hours (AUC0–24) and peak serum concentration from the dried powder were significantly (P<0.05) lower than the values from Cu B-PL/SDC-MMs in vivo. However, a better result was obtained for GL, ie, the drug was redispersed completely within 5 minutes in vitro. Further, absorption from the dried GL-PL/SDC-MM powder was increased to the same level as that for GL-PL/SDC-MMs in vivo compared with the control group. The difference in these results can be found in Cu B and GL. Cu B nanoparticles reagglomerated when released, resulting in slower redispersibility and less absorption compared with the original PL-SDC-MMs. However, no agglomeration or delay was observed for GL. A possible explanation is the difference in surface hydrophobicity between Cu B and GL. The results of this study not only show that spray granulation is an effective drying technique that can complement spray-drying and freeze-drying, but also confirm that the physicochemical properties of a drug have a significant influence on the in vitro and in vivo performance of the dried powder obtained after spray granulation.Keywords: cucurbitacin B, glycyrrhizin, mixed phospholipid-bile salt micelles, fluid bed granulation, poorly water soluble drugs