Nebulizers performance

Because the relationship between the physical characteristics and the nebulizer performance is less straightforward than expected, it should be stressed once again that laboratory evaluation of the specific drug formulation in combination with the intended nebulizers is required, before their use in vivo. 

Greenfield ef. ai.l l) observed a reduction of signal intensity that correlates with sample intake effects from the modified solution viscosity and/or surface tension of mineral acids. This, coupled with peristaltic pumping of solutions into the nebulizer, considerably reduces physical interferences. Increased salt concentration also has an effect on solution physical properties. In the experience of these authors, the high levels of salt in the matrix also increases the noise from the nebulizer system. This degradation of nebulizer performance, which is not necessarily accompanied by a proportional reduction in sensitivity, is the cause of the observed deterioration of detection limits in real samples as opposed to ideal solutions. 

As in all flame spectrometric techniques, care should be taken to make sure that the nebulizer performance, if the nebulizer is adjustable, is optimized. This may involve direct adjustment of the nebulizer capillary position or minor adjustments to the position of the impactor, if fitted. 

Dolovich, M. B. (2002), Assessing nebulizer performance, Respir. Care, 47, 1290-1301 discussion 1301-1304. 

Clark, AR. Shire, S.J. Formulation of Proteins for Pulmonary Delivery Protein and Formulation Delivery, McNahy, E.J., Ed. Marcel Dekker, Inc. New York, 2000 201-234. O Riordan, T.G. Formulations and nebulizer performance. Respir. Care 2002, 47 (11), 1305-1313. 

As with jet nebulizers and pMDIs, the formulation characteristics include liquid density, surface tension, viscosity, and vapor pressure. Many of these that effect nebulizer performance of formulation properties are described in the above equation. The configuration... 

Nebulizer Solutions The potential interactions that can occur in nebulizer solutions are subject to simple solution chemistry. A few excipients are employed in nebulizer products, notably sodium chloride to achieve isotonicity with body fluids. There are some rare examples in which interactions with sodium chloride and other solutes influence nebulizer performance. In studies of the delivery of amiloride hydrochloride and trisodium uridine triphosphate (UTP), both used in the treatment of cystic fibrosis, an interaction occurred in which a precipitate of the two drugs was formed in the ratio 3 amiloride 1 UTP.45 The presence of sodium chloride suppressed the solubility of amiloride further by the common ion effect. 

McPeck M, O Riordan TG, Smaldone GC. Choice of mechanical ventilator influence on nebulizer performance. Respir Care 1993 38 887-895. 

In the absence of clinical trials to establish safety and efficacy, assessment of efficiency of nebulizer systems relies largely on in vitro assessment of nebulizer performance. However, a number of factors conspire to confuse under-... 

A. British Standard on In Vitro Assessment of Nebulizer Performance... 

The first attempt by any nation to establish a standard method for assessing nebulizer performance was made in the U.K. in 1994. Though now outdated and technically limited (29), this published standard set a precedent and a foundation for further research and development of test methods. Much has happened to progress the understanding of nebulizer performance in recent years which has, in part, led to the development of the widely resourced European standard in assessing nebulizer performance. 

I have met very few employees who respect and appreciate annual performance appraisals. They do not see the evaluations as being fair, objective, and motivational. I am sure you know department heads and supervisors who complete performance appraisals only because it is mandatory. They are not interested in providing constructive, performance-focused feedback for continuous improvement. They do not maintain ongoing records of employees accomplishments and less-than-adequate performance. Instead, they typically wait until a few days before appraisals are due and then make their best-guess estimate of an individual s ranking, using nebulous performance dimensions like "competent," "enthusiastic," "self-motivated," "cooperative," "responsive to feedback," and "willing to improve."... 

Nebulizers perform the function of converting liquid samples to an aerosol, consisting of finely divided droplets, which are suspended in the plasma carrier gas. This aerosol, which is presumably representative of the composition of the original sample, is transported to the plasma torch, where it is injected into the central channel of the plasma for subsequent atomization and ionization. 

Jones, V. D. (1998). Evaluation of nebulizer performance within the ICP-MS measurement system of analysis of SRS radiological waste tank simulated solutions. ASTM Spec. Tech. Pub., p. 41. 

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