Effect of Processing Route on the Surface Properties of Amorphous Indomethacin Measured by Inverse Gas Chromatography

Burnett, Daniel J.; Khoo, Jiyi; Naderi, Majid; Heng, Jerry Y. Y.; Wang, G. D.; Thielmann, Frank

doi:10.1208/s12249-012-9881-5

Cited by 25 publications

(19 citation statements)

References 32 publications

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“…3 that the amount of amorphous content increases with increasing milling cycles. The amorphous state is reported to have higher surface energy compared to the crystalline state, suggesting that the increase in surface energy with increasing milling cycles can be attributed to the presence of surface amorphous content (Brum and Burnett, 2011;Burnett et al, 2012).…”

Section: Effect Of Milling Time and Temperature On Surface Energy Andmentioning

confidence: 99%

Effect of milling temperatures on surface area, surface energy and cohesion of pharmaceutical powders

Shah

Wang

Olusanmi

et al. 2015

International Journal of Pharmaceutics

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Particle bulk and surface properties are influenced by the powder processing routes. This study demonstrates the effect of milling temperatures on the particle surface properties, particularly surface energy and surface area, and ultimately on powder cohesion. An active pharmaceutical ingredient (API) of industrial relevance (brivanib alaninate, BA) was used to demonstrate the effect of two different, but most commonly used milling temperatures (cryogenic vs. ambient). The surface energy of powders milled at both cryogenic and room temperatures increased with increasing milling cycles. The increase in surface energy could be related to the generation of surface amorphous regions. Cohesion for both cryogenic and room temperature milled powders was measured and found to increase with increasing milling cycles. For cryogenic milling, BA had a surface area ∼ 5× higher than the one obtained at room temperature. This was due to the brittle nature of this compound at cryogenic temperature. By decoupling average contributions of surface area and surface energy on cohesion by salinization post-milling, the average contribution of surface energy on cohesion for powders milled at room temperature was 83% and 55% at cryogenic temperature.

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Section: Effect Of Milling Time and Temperature On Surface Energy Andmentioning

confidence: 99%

Effect of milling temperatures on surface area, surface energy and cohesion of pharmaceutical powders

Shah

Wang

Olusanmi

et al. 2015

International Journal of Pharmaceutics

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“…Burnett et al . [ 84 ] have investigated the effects of quench cooling and ball milling on the surface energy heterogeneity and surface chemistry of crystalline indomethacin (IMC). The surface energy distributions of crystalline, quench cooled and milled IMC samples are shown below in Fig.…”

Section: Powder Engineeringmentioning

confidence: 99%

Particle Engineering in Pharmaceutical Solids Processing: Surface Energy Considerations

Williams

2015

CPD

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During the past 10 years particle engineering in the pharmaceutical industry has become a topic of increasing importance. Engineers and pharmacists need to understand and control a range of key unit manufacturing operations such as milling, granulation, crystallisation, powder mixing and dry powder inhaled drugs which can be very challenging. It has now become very clear that in many of these particle processing operations, the surface energy of the starting, intermediate or final products is a key factor in understanding the processing operation and or the final product performance. This review will consider the surface energy and surface energy heterogeneity of crystalline solids, methods for the measurement of surface energy, effects of milling on powder surface energy, adhesion and cohesion on powder mixtures, crystal habits and surface energy, surface energy and powder granulation processes, performance of DPI systems and finally crystallisation conditions and surface energy. This review will conclude that the importance of surface energy as a significant factor in understanding the performance of many particulate pharmaceutical products and processes has now been clearly established. It is still nevertheless, work in progress both in terms of development of methods and establishing the limits for when surface energy is the key variable of relevance.

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“…Alternatively, IGC has the capability to characterize heterogeneous samples. 34 Based on Lewis acid and base theory, − was calculated as,…”

Section: Resultsmentioning

confidence: 99%

Adsorptive Recovery of Crude Oil Microdroplets from Wastewater Using Surface Engineered Sponges

Cherukupally¹,

Sun²,

Wong³

et al. 2019

Preprint

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In the US, the oil industry produces over 15 billion barrels of wastewater contaminated with crude oil microdroplets annually. Current technologies are unable to remove these microdroplets at different pH conditions. Herein, an innovative surface engineered sponge (SEnS) was designed by combining surface chemistry, surface charge, roughness, and surface energy. Under all pH conditions, the SEnS rapidly adsorbed oil microdroplets with 95-99% removal efficiency predominantly by Lifshitz-van der Waals forces. Furthermore, at the best pH value, 92% of the oil was adsorbed within 10 min due to synergistic Lifshitz-van der Waals and acid-base (electrostatic attractive interactions and hydrogen bond) forces. The adsorbed crude oil was recovered at ambient conditions while the cleaned SEnS was reused up to five times for crude oil adsorption. Due to the process efficacy, sponge reuse, and oil recovery, this adsorptive-recovery method using SEnS demonstrates great potential for the industrial recovery of oil from wastewater.Recently, surface engineered sponges (SEnS) have emerged as promising adsorbents for oil microdroplets. 7-9 Due to their low cost, ease of fabrication, and high uptake capacity, sponges have great potential as industrial-scale sorbents. 10 To date, most sponge surfaces have been tailored to adsorb surfactant-stabilized pure hydrocarbon emulsions, which exhibit monotonous wetting at different pH values. 7,8 In contrast, crude oil is a complex mixture of ionic, polar, and non-polar components. 11,12 As a result, depending on pH, these complex chemical mixtures can exhibit large variability in physicochemical properties 13,14 leading to a broad range of contact angles at a solid surface. 9 Furthermore, the fundamental mechanisms governing variation in crude oil wetting behaviour with pH, which are important for material design, are not well understood.This work develops new sponges that are robust to the variable pH-responsive wetting behaviour of crude oil. Desirable sponge surface properties for microdroplets adsorption over broad pH conditions were hypothesized. To complement crude oil composition variability, the sponge surface is predicted to need organic, acid and base sites for effective oil adsorption (Figure 1a).Along with tailored surface chemistry, 15-17 the surface charge, [17][18][19] and roughness 20-22 may also invoke favorable wetting behavior 23-26 at the sponge surface (Figure 1b), enabling adsorption of oil droplets over a broad pH range. Based on these properties, the crude oil adsorption process efficacy can be predicted and validated experimentally.Herein, the aforementioned approach was applied to develop SEnS for adsorptive recovery of crude oil microdroplets for variable pH conditions. The SEnS consists of an acid-base polyester Affiliations

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Effect of Processing Route on the Surface Properties of Amorphous Indomethacin Measured by Inverse Gas Chromatography

Cited by 25 publications

References 32 publications

Effect of milling temperatures on surface area, surface energy and cohesion of pharmaceutical powders

Effect of milling temperatures on surface area, surface energy and cohesion of pharmaceutical powders

Particle Engineering in Pharmaceutical Solids Processing: Surface Energy Considerations

Adsorptive Recovery of Crude Oil Microdroplets from Wastewater Using Surface Engineered Sponges

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