Spray Congealing: Particle Size Relationships Using a Centrifugal Wheel Atomizer

Scott, Morton W.; Robinson, Manford J.; Pauls, John F.; Lantz, Russell J.

doi:10.1002/jps.2600530621

Cited by 29 publications

(6 citation statements)

References 6 publications

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“…Hydrophilic matrix materials, often used for enhancing drug release, include various grades of polyethylene glycols 25 , poloxamers 26 and gelucires 27 . On the other hand, hydrophobic matrix materials have been used for taste masking and sustaining drug release, and include waxes 28 , glycerides 29 , hydrogenated vegetable oils 30 and fatty acids 31 . Typically, formulations for spray congealing consist of the matrix material, active substance(s) with or without other additives such as those used as release modifiers.…”

Section: Introductionmentioning

confidence: 99%

A study on the solid state characteristics of spray-congealed glyceryl dibehenate solid lipid microparticles containing ibuprofen

Wong

Heng

Chan

2015

Drug Development and Industrial Pharmacy

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Section: Introductionmentioning

confidence: 99%

A study on the solid state characteristics of spray-congealed glyceryl dibehenate solid lipid microparticles containing ibuprofen

Wong

Heng

Chan

2015

Drug Development and Industrial Pharmacy

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“…Historically, knowledge of viscosity was used mainly as a means of characterising and classifying fluids and semi‐solids . However, in recent years, viscosity is increasingly recognised as a fundamental physicochemical property affecting many pharmaceutical processes, particularly melt processes , such as melt granulation and spray congealing . The viscosity of the molten feed (for spray congealing) or the molten binder (for melt granulation) is dependent on the physical properties of the meltable material as well as the amount of drug or additive dispersed within it.…”

Section: Introductionmentioning

confidence: 99%

“…Besides safety issues, the latter may affect drug stability, thereby negating the primary benefits of the process. Potential matrix materials should also be thermally stable so that they do not decompose upon heating during the feed preparatory step . They may be hydrophilic or hydrophobic.…”

Section: Introductionmentioning

confidence: 99%

“…The effect of decreasing melt viscosity is similarly inconclusive in other studies. Maschke's work employing glyceryl tripalmitate as matrix material and insulin as additive concluded that a lower melt viscosity resulted in smaller particles whereas Scott's investigation on stearic acid as matrix material and ethylcelluose as viscosity‐modifying additive concluded otherwise .…”

Section: Introductionmentioning

confidence: 99%

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Viscosity–temperature relationship of lipid‐based excipients amenable for spray congealing: Derivation of a rheological parameter with good correlation to particle size

Wong

Heng

Chan

2015

Euro J Lipid Sci & Tech

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The objective of this paper was to investigate the viscosity‐temperature relationship of lipid‐based materials (fatty alcohol, fatty acid, fatty ester and glycerides) amenable for spray congealing. The flow properties and viscosity–temperature relationship of cetyl alcohol, stearic acid, myristyl myristate, glyceryl monostearate, glyceryl dibehenate, hydrogenated soybean oil, hydrogenated vegetable oil and hydrogenated cottonseed oil were investigated using continuous ramping and temperature ramping tests. The viscosity–temperature data obtained was fitted into two existing viscosity–temperature models as well as a series of mathematical functions. The peak melting points of the materials were established by differential scanning calorimetry. Morphology and size of the spray‐congealed microparticles were analysed by scanning electron microscopy and laser diffractometry. Correlation analyses were conducted to explore the relationship between viscosity and microparticle median size. When molten, all eight lipid‐based materials used were Newtonian liquids. Viscosity of these materials decreased in a biphasic manner with increasing temperature which fitted a simple biexponential equation. The viscosity–temperature curves showed distinct transition points, from which mathematical manipulations generated a new rheological parameter termed Tp. Compared to the conventionally used viscosity values at spraying temperature, the Tp values of materials showed a stronger correlation with the median size of spray‐congealed microparticles produced. Practical applications: From this work, a new temperature‐independent constant (Tp) unique to each lipid‐based material was derived and found to have good correlation with the resultant spray‐congealed microparticle median size. This work aims to introduce Tp as a viable parameter of the rheology of lipid‐based materials for optimisation of formulation in spray congealation. Besides spray congealing, the application of Tp may be extended to other melt processes, such as melt granulation, melt extrusion and hot melt coating. (A) A typical biexponential temperature ramping curve showing the location of the characteristic transition point (Tp). (B) Graph of median size (μm) of spray‐congealed microparticles against Tp values.

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“…Viscosity, a fundamental physicochemical property affecting spray congealing [ 1 , 17 , 33 , 55 , 56 ], is the measure of a material’s resistance to flow. In spray congealing, viscosity of the molten feed is influenced by several factors such as the nature of the matrix material, the amount of drug or additive used, and the atomization air temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of Lipid Additives and Drug on the Rheological Properties of Molten Paraffin Wax, Degree of Surface Drug Coating, and Drug Release in Spray-Congealed Microparticles

et al. 2018

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Paraffin wax is potentially useful for producing spray-congealed drug-loaded microparticles with sustained-release and taste-masking properties. To date, there is little information about the effects of blending lipids with paraffin wax on the melt viscosity. In addition, drug particles may not be entirely coated by the paraffin wax matrix. In this study, drug-loaded paraffin wax microparticles were produced by spray-congealing, and the effects of lipid additives on the microparticle production were investigated. The influence of lipid additives (stearic acid, cetyl alcohol, or cetyl esters) and drug (paracetamol) on the rheological properties of paraffin wax were elucidated. Fourier transform-infrared spectroscopy was conducted to investigate the interactions between the blend constituents. Selected formulations were spray-congealed, and the microparticles produced were characterized for their size, drug content, degree of surface drug coating, and drug release. The viscosity of wax-lipid blends was found to be mostly lower than the weighted viscosity when interactions occurred between the blend constituents. Molten paraffin wax exhibited Newtonian flow, which was transformed to plastic flow by paracetamol and pseudoplastic flow by the lipid additive. The viscosity was decreased with lipid added. Compared to plain wax, wax-lipid blends produced smaller spray-congealed microparticles. Drug content remained high. Degree of surface drug coating and drug release were also higher. The lipid additives altered the rheological properties and hydrophobicity of the melt and are useful for modifying the microparticle properties.

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Spray Congealing: Particle Size Relationships Using a Centrifugal Wheel Atomizer

Cited by 29 publications

References 6 publications

A study on the solid state characteristics of spray-congealed glyceryl dibehenate solid lipid microparticles containing ibuprofen

A study on the solid state characteristics of spray-congealed glyceryl dibehenate solid lipid microparticles containing ibuprofen

Viscosity–temperature relationship of lipid‐based excipients amenable for spray congealing: Derivation of a rheological parameter with good correlation to particle size

Effect of Lipid Additives and Drug on the Rheological Properties of Molten Paraffin Wax, Degree of Surface Drug Coating, and Drug Release in Spray-Congealed Microparticles

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