Analysis of the influence of relative humidity on the moisture sorption of particles and the aerosolization process in a dry powder inhaler

Zhu, Kewu; Tan, Reginald B. H.; Ng, Wai Kiong; Shen, Shoucang; Zhou, Qi Tony; Heng, Paul Wan Sia

doi:10.1016/j.jaerosci.2008.02.003

Cited by 53 publications

(28 citation statements)

References 38 publications

(47 reference statements)

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“…Previous research work has presented data that relates high dust contamination to high fungi aerossolization [41,42], corroborating this association. Regarding the WWTP setting, differences regarding the number of species isolated in the air and in the surface samples were the most notorious, probably due to the high levels of moisture that may reduce dust aerossolization and, consequently, also decrease the number of fungal species found in the air [43,44]. Molecular techniques have been often used to measure single species in the air using qPCR techniques [26].…”

Section: Discussionmentioning

confidence: 99%

Analysis of surfaces for characterization of fungal burden – Does it matter?

Viegas¹,

Faria²,

Meneses³

et al. 2016

Int J Occup Med Environ Health

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Objectives: Mycological contamination of occupational environments can be a result of fungal spores' dispersion in the air and on surfaces. Therefore, it is very important to assess it in both types of the samples. In the present study we assessed fungal contamination in the air and in the surface samples to show relevance of surfaces sampling in complementing the results obtained in the air samples. Material and Methods: In total, 42 settings were assessed by the analysis of air and surfaces samples. The settings were divided into settings with a high fungal load (7 poultry farms and 7 pig farms, 3 cork industries, 3 waste management plants, 2 wastewater treatment plants and 1 horse stable) and a low fungal load (10 hospital canteens, 8 college canteens and 1 maternity hospital). In addition to culture-based methods, molecular tools were also applied to detect fungal burden in the settings with a higher fungal load. Results: From the 218 sampling sites, 140 (64.2%) presented different species in the examined surfaces when compared with the species identified in the air. A positive association in the high fungal load settings was found between the presence of different species in the air and surfaces. Wastewater treatment plants constituted the setting with the highest number of different species between the air and surface. Conclusions: We observed that surfaces sampling and application of molecular tools showed the same efficacy of species detection in high fungal load settings, corroborating the fact that surface sampling is crucial for a correct and complete analysis of occupational scenarios.

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Section: Discussionmentioning

confidence: 99%

Analysis of surfaces for characterization of fungal burden – Does it matter?

Viegas¹,

Faria²,

Meneses³

et al. 2016

Int J Occup Med Environ Health

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“…The SS contents in cSS-mLAC comilled mixtures were analyzed by HPLC using the method developed by Zhu et al 34 The measured retention time for SS was approximately 3.9 min. Standard solutions were prepared for drug concentrations ranging from 0.5 to 15 mg/mL, in order to construct a calibration curve of drug concentration against the peak area.…”

Section: High Pressure Liquid Chromatographymentioning

confidence: 99%

Influence of excipients in comilling on mitigating milling-induced amorphization or structural disorder of crystalline pharmaceutical actives

Balani

Tan

et al. 2010

Journal of Pharmaceutical Sciences

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“…But, at high RH values water will form a complete monolayer of water molecules on the surface of the crystalline solid particles [118], leading to increased interparticle adhesion forces due to increased specific capillary (liquid bridge) forces, which function as drug-carrier adhesion forces resulting in poor powder deaggregation (i.e. poor drug-carrier detachment) during aerosolisation [41,100,[119][120][121]. It should also be noted that environmental humidity during blending could have a considerable effect on the size distribution of the investigated particles.…”

Section: Moisture Uptake and Environmental Humiditymentioning

confidence: 99%

On the effects of blending, physicochemical properties, and their interactions on the performance of carrier-based dry powders for inhalation — A review

Kaialy

2016

Advances in Colloid and Interface Science

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Blending drug and carrier powders to produce homogeneous drug-carrier adhesive mixtures is a key step in the production of dry powder inhaler (DPI) formulations. Although the blending conditions can result in different conclusions or probably change the outcome of a study entirely if being selected differently, there is a scarcity of data on the influence of blending processes on the physicochemical properties of bulk powder formulations and the follow-on effects on DPI performance. This paper provides an overview of the interactions between variables related to blending conditions (e.g. blending equipment, time, speed and sequence as well as environmental humidity) and powder physicochemical properties (e.g. size distribution, shape distribution, density, anomeric composition, electrostatic charge, surface, and bulk properties), and their effects on the performance of adhesive mixtures for inhalation in terms of drug content homogeneity, drug-carrier adhesion, and drug aerosolisation behaviour. The relevance of carrier payload, batch size and segregation was also discussed. Challenges and future directions were identified. This review therefore contributes towards a better understanding of the blending process, powder physicochemical properties, and their interlinked effects on the fundamental understanding of adhesive mixtures for inhalation. The knowledge gained is essential to ensure optimum blending and thereby controlled functionality of DPIs.

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Analysis of the influence of relative humidity on the moisture sorption of particles and the aerosolization process in a dry powder inhaler

Cited by 53 publications

References 38 publications

Analysis of surfaces for characterization of fungal burden – Does it matter?

Analysis of surfaces for characterization of fungal burden – Does it matter?

Influence of excipients in comilling on mitigating milling-induced amorphization or structural disorder of crystalline pharmaceutical actives

On the effects of blending, physicochemical properties, and their interactions on the performance of carrier-based dry powders for inhalation — A review

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