Browsing by Author "Lu, Tiejun"

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    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, Andrew
    Dry 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.
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    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.