Quantifying electrostatic interactions in pharmaceutical solid systems

Rowley, G.

doi:10.1016/s0378-5173(01)00784-0

Cited by 89 publications

(62 citation statements)

References 11 publications

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“…The charge duration on a surface depends on relaxation time, which is the product of permittivity and surface resistivity of materials. As the majority of pharmaceutical materials are insulators, this process is extended, perhaps over minutes to hours, in comparison to conductive materials (Bailey, 1984;Rowley, 2001). A fundamental understanding of the phenomenon is still elusive (Soh et al, 2012), however, on the basis of existing theories, the mechanism of charge generation can be due to electron transfer, (charge is produced due to the flow of electrons between particles); ion transfer (diffusion of ions between the surface of particles); or due to material transfer (some material is rubbed off from one contacting body and attached onto the surface of another particle).…”

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confidence: 99%

“…The chemical structure, functional groups, surface chemistry (Kamiyama et al, 1994;Mazumder et al, 2006;Shinohara et al, 1976), particle size, shape, surface roughness (Carter et al, 1998;Eilbeck et al, 1999;Traini et al, 2012) and electrical properties of powders and contacting surfaces (Bailey and Smedley, 1991;Rowley, 2001) can all affect the tribo-electrification process and subsequent particle surface adhesion. Moreover, the charge transfer process is further complicated due to external factors that may influence the charging process including relative humidity, temperature, nature of contacting material and the velocity of particles (Matsusaka et al, 2010).…”

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confidence: 99%

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Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

Ghori

Šupuk

Conway

2014

European Journal of Pharmaceutical Sciences

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The pervasiveness of tribo-electric charge during pharmaceutical processing can lead to the exacerbation of a range of problems including segregation, content heterogeneity and particle surface adhesion. The excipients, hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC), are often used in drug delivery systems and so it is important to understand the impact of associated factors on their charging and adhesion mechanisms, however, little work has been reported in this area. Such phenomena become more prominent when excipients are introduced to a powder mixture alongside the active pharmaceutical ingredient(s) (APIs) with inter-and intra-particulate interactions giving rise to electrification and surface adhesion of powder particles. The aim of this study was to understand the impact of material attributes (particle size, hydroxypropoxyl (Hpo) to methoxyl (Meo) ratio and molecular size) on the charging and adhesion characteristics of cellulose ethers. Furthermore, a poorly compactible and highly electrostatically charged drug, flurbiprofen, was used to develop binary powder mixtures having different polymer to drug ratios and the relationship between tribo-electric charging and surface adhesion was studied. Charge was induced on powder particles and measured using a custom built device based on a shaking concept, consisting of a Faraday cup connected to an electrometer. The diversity in physicochemical properties has shown a significant impact on the tribo-electric charging and adhesion behaviour of MC and HPMC.Moreover, the adhesion and electrostatic charge of the API was significantly reduced when MC and HPMC were incorporated and tribo-electric charging showed a linear relationship (R 2 = 0.81-0.98) with particle surface adhesion, however, other factors were also involved. It is anticipated that such a reduction in charge and particle surface adhesion would improve flow and compaction properties during processing.

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confidence: 99%

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confidence: 99%

Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen

Ghori

Šupuk

Conway

2014

European Journal of Pharmaceutical Sciences

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“…Detailed studies on particle sizes have suggested that the magnitude of the charge increases continuously with a decrease in particle size, as indicated in Table 4 [69]. A possible reason is thought to be the adhesion of fine particles (<40 μm) to coarse particles, which eventually enhance the surface roughness of the coarse particles, similar to the effects of the pattern/ microstructure shown in Table 4.…”

Section: Particle Sizementioning

confidence: 79%

Fundamental theories and basic principles of triboelectric effect: A review

2018

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Long-term observation of the triboelectric effect has not only proved the feasibility of many novel and useful tribo-devices (e.g., triboelectric nanogenerators), but also constantly motivated the exploration of its mysterious nature. In the pursuit of a comprehensive understanding of how the triboelectric process works, a more accurate description of the triboelectric effect and its related parameters and factors is urgently required. This review critically goes through the fundamental theories and basic principles governing the triboelectric process. By investigating the difference between each charging media, the electron, ion, and material transfer is discussed and the theoretical deduction in the past decades is provided. With the information from the triboelectric series, interesting phenomena including cyclic triboelectric sequence and asymmetric triboelectrification are precisely analyzed. Then, the interaction between the tribo-system and its operational environment is analyzed, and a fundamental description of its effects on the triboelectric process and results is summarized. In brief, this review is expected to provide a strong understanding of the triboelectric effect in a more rigorous mathematical and physical sense.

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“…This may, in part, be attributed to the small size of IND in comparison to ARG (Fig. 1) since it has been reported that small particles may carry higher charge density than large particles [24]. It is believed that smaller particles have larger specific surface area which in turn increases the number of contacts between particles and surrounding surfaces.…”

Section: Powder Characterisationmentioning

confidence: 97%