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Aerosols, Calorimetry, Differential Scanning, Cellulose, Chemistry, Pharmaceutical, Cyclooxygenase Inhibitors, Diclofenac, Drug Carriers, Microscopy, Electron, Microspheres, Particle Size, Spectroscopy, Fourier Transform Infrared, Technology, Pharmaceutical


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OBJECTIVE: To examine the potential of a novel 3-fluid nozzle spray drying technology to formulate differentiated layered microparticles (MPs) of diclofenac sodium (DFS)/ethyl cellulose (EC).

METHODS: DFS/EC MPs were formulated using the inner and/or outer nozzles of a novel 3-fluid nozzle and compared with MPs formed using conventional (2-fluid) spray drying. MPs were characterised for particle size and for morphology by TEM and SEM. Distribution of DFS and EC of MPs was analysed by FT-IR and DSC. A two-factor, three-level (3(2)) factorial design was applied to investigate the effect and interaction of total feed solid content (TSC) and feed flow rate (FFR) on MP size, D(50%) and D(90%), bulk density and MP yield.

RESULTS: Interestingly, TEM demonstrated that MPs formed by 3-fluid nozzle spray drying showed a heterogeneous internal morphology consisting of a core and coat, characteristic of a microcapsule. In comparison, MPs from conventional spray drying showed a homogeneous internal morphology, characteristics of a matrix system. This differential distribution of DFS/EC was supported by FT-IR and DSC. Results of multiple linear regression analysis showed a linear relationship for the effect of TSC and FFR on all responses except for D(50%) where a quadratric model was valid. The effect of TSC/FFR on MP size and yield was similar to conventional spray drying.

CONCLUSION: The novel 3-fluid nozzle spray drying offers a new method of designing layered microparticles or microcapsules which can have wide applications from drug stabilisation to controlled drug delivery and targeting.


Pharmacy and Pharmaceutical Sciences


Pabari RM, Sunderland T, Ramtoola Z. Investigation of a novel 3-fluid nozzle spray drying technology for the engineering of multifunctional layered microparticles. Expert Opinion on Drug Delivery. 2012 Dec;9(12):1463-74.

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