Abstract
Production of active ingredients such as pharmaceuticals in nano-particulate form is highly desirable but the resulting product is difficult to handle and to use in applications. A novel process is described for coating nanoparticles onto excipient particles of c. 300μm by rapid expansion of a supercritical solution (RESS) into two types of modified proprietary equipment: a Wurster coater and a fluidized bed. This novel approach has been demonstrated through the successful deposition of six mimics for active ingredients (benzoic acid, adamantane, ferrocene, phenanthrene, stearic acid and vitamin K3) on carrier excipient particles of microcrystalline cellulose (MCC). Evidence from SEM, EDX and Confocal Raman microscopy suggests that the coating particles are below 30nm in size. Unlike most conventional coating processes, this approach avoids the use of liquids and high temperatures. As a wide range of actives and excipients can potentially be employed, the approach is applicable across the process and product industries, in particular pharmaceutical, household goods, personal care and catalyst industries.
Highlights
Active ingredients in nanoparticulate form can have advantageous properties; for example, nanoparticulate drugs can show higher bioavailability [1] and catalysts higher activity [2]
In both rapid expansion of supercritical solutions (RESS)-WTS and RESS-BFB coating procedures the distance between the nozzle and microcrystalline cellulose (MCC) particles in the bed was kept to a minimum, i.e. the fluidized bed was in direct contact with the surface of the gas distributor plate, into which the nozzle was inserted, so that its tip was slightly countersunk (∼15 mm) into the plate
The colour change of MCC before and after coating in the RESSWurster coater was used as a visual indication of the success of the process (Fig. 2)
Summary
Active ingredients in nanoparticulate form can have advantageous properties; for example, nanoparticulate drugs can show higher bioavailability [1] and catalysts higher activity [2]. Nucleation in the expanding RESS jet occurs very close to the origin of the jet [14] and it is difficult to prevent agglomeration from occurring before any stabilization treatment can be applied; evidence from other workers [15] suggests that the RESS product is usually in aggregated form It would be advantageous, to capture and preserve the active particles close to their origin, for subsequent processing or re-dispersion. Wang et al [24] used the RESS technique to precipitate PVC covinyl acetate and hydroxypropyl cellulose onto 315 and 500 m glass spheres placed in a collector vessel held at a pressure and temperature intermediate between supercritical and ambient They added acetone to the CO2 in order to enhance solubility of the polymer. The work reported here is distinct from previous studies in that it is aimed exclusively at production of nanoparticles and their capture onto larger carriers which are freely fluidizable and suitable for subsequent handling
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
