Browsing by Author "Lu, Tiejun"
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Item Open Access Analysis of curcumin precipitation and coating on lactose by the integrated supercritical antisolvent-fluidized bed process(Elsevier, 2017-12-12) Matos, Ravenna Lessa; Lu, Tiejun; McConville, Christopher; Leeke, Gary; Ingram, AndrewDry powder formulations with potential application in pulmonary drug delivery were produced by integrating the Supercritical Antisolvent (SAS) process with a fluidized bed (FB) under pressure. The simultaneous precipitation and coating of curcumin on lactose was performed in a single step combining the advantages of both processes. Ethanol and acetone were used as solvents. The effects of operating parameters: pressure, temperature, drug-lactose mass ratio, solution flow rate and solution concentration on the drug size, morphology and yield were investigated. Due to the high degree of mixing in the fluidized bed, a uniform coating of curcumin onto lactose was achieved with loading efficiency varying from 71.0 to 93.3% and curcumin particle size between 0.41 and 12.08 μm. Solvent-free curcumin particles with reduced crystallinity were produced while the physicochemical properties of the raw materials were not changed.Item Open Access Supercritical fluid coating of API on excipient enhances drug release(Elsevier, 2016-12-18) Li, Qingguo; Huang, Deen; Lu, Tiejun; Seville, Jonathan P. K.; Xing, Lei; Leeke, Gary A.A process to coat particles of active pharmaceutical ingredient (API) onto microcrystalline cellulose (MCC) excipient shows promise as a new way to dosage forms showing enhanced drug release. The process consists of a fluidized bed operated at elevated pressure in which API particles are precipitated from a Supercritical Anti-Solvent process (SAS). MCC particles were used as an excipient in the fluidized bed and collect the SAS-generated API particles. Naringin was selected as the model API to coat onto MCC. A number of operational parameters of the process were investigated: fluidization velocity, coating pressure, temperature, concentration of drug solution, drug solution flow rate, drug mass, organic solvent, MCC mass and size and CO2-to-organic solution ratio. SEM and SPM analyses showed that the MCC particle surfaces were covered with near-spherical nanoparticles with a diameter of approximately 100–200 nm, substantially smaller than the as-received API material. XRD showed that naringin changed from crystalline to amorphous during processing. The coated particles resulting from the SAS fluidized bed process have a higher loading of API, gave faster release rates and higher release ratios in comparison with those produced using a conventional fluidized bed coating process. The approach could be transferred to other industries where release is important such as agrochemical, cosmetic and food.