Polymeric materials formed by precipitation with a compressed fluid antisolvent

Dixon, David; Johnston, Keith P.; Bodmeier, Roland

doi:10.1002/aic.690390113

Cited by 308 publications

(194 citation statements)

References 45 publications

(41 reference statements)

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“…It confirmed the observations by Randolph et al (1993) that fiber formation at solution concentrations exceeding 4% w/v L-PLA in methylene chloride was found (20). Similar observations were also reported for the polystyrene/ toluene/CO 2 system, where a critical composition of approximately 5% w/v was reported (36). However, in this study, the microparticles processed from the absolute concentration of 3% w/v of rifampicin and L-PLA consistently provided the discrete microparticles; their particle sizes were slightly larger than those of 1% and 2% w/v.…”

Section: Resultssupporting

confidence: 79%

“…It was observed that the percent fraction <5 μm size using operating pressure at 138 bar was apparently lower than those prepared at 172 and 207 bar. Dixon et al (1993) found a decrease in particle size of product prepared from the mixture of polystyrene in toluene solution and carbon dioxide if the density of the Table I Operating condition extracting gas was raised by increasing operating pressure, which was also in agreement with the report by Kim et al (21,36). The effect of temperature was studied by varying operating temperature at 33, 40, and 50°C while maintaining all other variables constant: operation pressure of 172 bar, 2% w/v solution with carbon dioxide mole fraction at 0.82.…”

Section: Resultsmentioning

confidence: 99%

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Formation of Inhalable Rifampicin–Poly(l-lactide) Microparticles by Supercritical Anti-solvent Process

2008

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Abstract. Formation of inhalable microparticles containing rifampicin and poly(L-lactide) (L-PLA) by using supercritical anti-solvent process (SAS) was investigated. The solutions of drug and polymer in methylene chloride were sprayed into supercritical carbon dioxide. The effect of polymer content and operating conditions, temperature, pressure, carbon dioxide molar fraction, and concentration of solution, on product characteristics were studied. The prepared microparticles were characterized with respect to their morphology, particle size and size distribution, drug content, drug loading efficiency, and drug release characteristic. Discrete, spherical microparticles were obtained at high polymer:drug ratios of 7:3, 8:2, and 9:1. The shape of L-PLA microparticles became more irregular and agglomerated with decreasing polymer content. Microparticles with polymer content higher than 60% exhibited volumetric mean diameter less than 5 μm, but percent drug loading efficiency was relatively low. Drug-loaded microparticles containing 70% and 80% L-PLA showed a sustainable drug release property without initial burst release. Operating temperature level influenced on mean size and size distribution of microparticles. The operating pressure and carbon dioxide molar fraction in the range investigated were unlikely to have an effect on microparticle formation. An increasing concentration of feed solution provided larger size microparticles. Rifampicin-loaded L-PLA microparticles could be produced by SAS in a size range suitable for dry powder inhaler formulation.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Formation of Inhalable Rifampicin–Poly(l-lactide) Microparticles by Supercritical Anti-solvent Process

2008

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“…About ternary mixtures, which are mostly related to SAS, a phase behavior study of the system is extremely useful to address the feasibility of the process and to exploit the effects of T and P [74]. Moreover, alternative polymeric particle topography and shapes depended upon process paths followed in the phase diagram were reported.…”

Section: Thermodynamics Studymentioning

confidence: 99%

Tailoring Particle Microstructures via Supercritical CO<sub>2</sub> Processes for Particular Drug Delivery

Liu¹,

Jiang

Wang³

2015

CPD

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Strategies for a particular drug delivery are always of great interest for the pharmaceutical industry, and efficient methods of preparing products with controlled particle microstructures are fundamental for the development and application of drug delivery. Supercritical fluid particle design (SCF PD) processes, as a green and effective alternative to traditional methods, have been effectively employed to produce particles with designated microstructures.Combining with research experiences in our research group, this review aims to provide a theoretical framework of SCF PD for particular drug delivery. For any drug delivery formulations, macroscopic properties are directly influenced by the particle microstructures, "Inverse" strategies are introduced at first to obtain the needed particle microstructures for a particular drug delivery in this paper. Then, how to produce particles with designated microstructures via SCF PD processes is discussed, mainly focus on the screening and selection of operating parameters according to thermodynamics and fluid dynamics study. Recent examples of SCF micronization and co-precipitation/ encapsulation processes are also summarized with an emphasis on how to tailor the particle microstructures by controlling the operating parameters.Finally, challenges and issues needed further study are briefly suggested for SCD PD.

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“…Moussa et al (Moussa et al, 2005) showed that the pressure distribution during the expansion of the supercritical fluid is a function of the nozzle length and diameter. Other authors used small internal diameter capillaries (Dixon et al, 1993;Randolph et al, 1993). Coaxial devices have also been proposed: in the SEDS process (solution enhanced dispersion by supercritical fluids) a coaxial twin-fluid nozzle to co-introduce the SCF antisolvent and solution is used (Bałdyga et al, 2010;He et al, 2010;Mawson et al, 1997;Wena et al, 2010).…”

Section: Parameters Influence On Hydrodynamicmentioning

confidence: 99%