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Joseph M Desimone - One of the best experts on this subject based on the ideXlab platform.

  • formulation of high performance dry powder aerosols for pulmonary protein delivery
    Pharmaceutical Research, 2018
    Co-Authors: Erin M Wilson, Christopher J Luft, Joseph M Desimone
    Abstract:

    Pulmonary delivery of biologics is of great interest, as it can be used for the local treatment of respiratory diseases or as a route to systemic drug delivery. To reach the full potential of inhaled biologics, a formulation platform capable of producing high performance aerosols without altering protein native structure is required. A formulation strategy using Particle Replication in Non-wetting Templates (PRINT) was developed to produce protein dry powders with precisely engineered particle morphology. Stability of the incorporated proteins was characterized and the aerosol properties of the protein dry powders was evaluated in vitro with an Andersen Cascade Impactor (ACI). Model proteins bovine serum albumin (BSA) and lysozyme were micromolded into 1 μm cylinders composed of more than 80% protein, by mass. Extensive characterization of the incorporated proteins found no evidence of alteration of native structures. The BSA formulation produced a mass median aerodynamic diameter (MMAD) of 1.77 μm ± 0.06 and a Geometric Standard Deviation (GSD) of 1.51 ± 0.06 while the lysozyme formulation had an MMAD of 1.83 μm ± 0.12 and a GSD of 1.44 ± 0.03. Protein dry powders manufactured with PRINT could enable high-performance delivery of protein therapeutics to the lungs.

  • formulation of high performance dry powder aerosols for pulmonary protein delivery
    Pharmaceutical Research, 2018
    Co-Authors: Erin M Wilson, Christopher J Luft, Joseph M Desimone
    Abstract:

    Purpose Pulmonary delivery of biologics is of great interest, as it can be used for the local treatment of respiratory diseases or as a route to systemic drug delivery. To reach the full potential of inhaled biologics, a formulation platform capable of producing high performance aerosols without altering protein native structure is required. Methods A formulation strategy using Particle Replication in Non-wetting Templates (PRINT) was developed to produce protein dry powders with precisely engineered particle morphology. Stability of the incorporated proteins was characterized and the aerosol properties of the protein dry powders was evaluated in vitro with an Andersen Cascade Impactor (ACI). Results Model proteins bovine serum albumin (BSA) and lysozyme were micromolded into 1 μm cylinders composed of more than 80% protein, by mass. Extensive characterization of the incorporated proteins found no evidence of alteration of native structures. The BSA formulation produced a mass median aerodynamic diameter (MMAD) of 1.77 μm ± 0.06 and a Geometric Standard Deviation (GSD) of 1.51 ± 0.06 while the lysozyme formulation had an MMAD of 1.83 μm ± 0.12 and a GSD of 1.44 ± 0.03. Conclusion Protein dry powders manufactured with PRINT could enable high-performance delivery of protein therapeutics to the lungs.

Susan Walker - One of the best experts on this subject based on the ideXlab platform.

  • calculating the interindividual Geometric Standard Deviation for use in the integrated exposure uptake biokinetic model for lead in children
    Environmental Health Perspectives, 1999
    Co-Authors: Susan Griffin, Allan H. Marcus, Terry W. Schulz, Susan Walker
    Abstract:

    The integrated exposure uptake biokinetic (IEUBK) model, recommended for use by the U.S. Environmental Protection Agency at residential Superfund sites to predict potential risks to children from l...

  • Calculating the interindividual Geometric Standard Deviation for use in the integrated exposure uptake biokinetic model for lead in children.
    Environmental health perspectives, 1999
    Co-Authors: Susan Griffin, Allan H. Marcus, Terry W. Schulz, Susan Walker
    Abstract:

    The integrated exposure uptake biokinetic (IEUBK) model, recommended for use by the U.S. Environmental Protection Agency at residential Superfund sites to predict potential risks to children from lead exposure and to establish lead remediation levels, requires an interindividual Geometric Standard Deviation (GSDi) as an essential input parameter. The GSDi quantifies the variability of blood lead concentrations for children exposed to similar environmental concentrations of lead. Estimates of potential risks are directly related to the GSDi, and therefore the GSDi directly impacts the scope of remediation at Superfund sites. Site-specific GSDi can be calculated for sites where blood lead and environmental lead have been measured. This paper uses data from blood and environmental lead studies conducted at the Bingham Creek and Sandy, Utah, Superfund sites to calculate GSDi using regression modeling, box modeling, and structural equation modeling. GSDis were calculated using various methods for treating values below the analytical method detection and quantitation limits. Treatment of nonquantifiable blood lead concentrations affected the GSDi more than the statistical method used to calculate the GSDi. For any given treatment, the different statistical methods produced similar GSDis. Because of the uncertainties associated with data in the blood lead studies, we recommend that a range of GSDis be used when analyzing site-specific risks associated with exposure to environmental lead instead of a single estimate. Because the different statistical methods produce similar GSDis, we recommend a simple procedure to calculate site-specific GSDi from a scientifically sound blood and environmental lead study.

Wei Peng - One of the best experts on this subject based on the ideXlab platform.

  • an analytical solution of the population balance equation for simultaneous brownian and shear coagulation in the continuum regime
    Advanced Powder Technology, 2020
    Co-Authors: Kaiyuan Wang, Wei Peng
    Abstract:

    Abstract Brownian coagulation of aerosol particles can take place in both laminar and turbulent flows. Thus, the simultaneous Brownian and shear coagulation will always occur in practical applications. This study presents an analytical solution to describe the size evolution of polydisperse particles undergoing simultaneous Brownian and shear coagulation. The analytical solution is derived using the log-normal method of moments (LNMOM) with some approximations. Then, the analytical solution is validated by comparing with previous analytical solutions derived for limiting cases. The results show that the present analytical solution is consistent with previous analytical solutions for these limiting cases. Further, the time trajectories of the total particle number concentration, the Geometric Standard Deviation and the Geometric number mean particle volume predicted by the present analytical solution are compared with those of a numerical LNMOM model. The results show that the present analytical solution gives good predictions of the total particle number concentration but less accurate predictions of the Geometric Standard Deviation and the Geometric number mean particle volume. A dimensionless analysis shows that the coagulation rate ratio and the initial polydispersity are two important factors for characterizing the size evolution of simultaneous Brownian and shear coagulation.

  • a new approximation approach for analytically solving the population balance equation due to thermophoretic coagulation
    Journal of Aerosol Science, 2019
    Co-Authors: Kaiyuan Wang, Wei Peng
    Abstract:

    Abstract The analytical solution of the population balance equation (PBE) for coagulation by differential settling velocities remains a challenging issue due to the absolute value in the collision kernel. A Geometric mean approximation approach is first proposed in this study to handle the integration of the absolute value and convert the moment equation into an integrable form. Using this approach along with the log-normal method of moments, the PBE is first analytically solved for thermophoretic coagulation in the low Knudsen number limit. The present analytical solution is validated by comparing the size distribution parameters with the sectional method. The maximum relative errors in this study are quite acceptable as compared with previous analytical solutions for Brownian coagulation. Moreover, the self-preserving size distribution predicted by the present analytical solution compares well with the sectional method and previous numerical studies on thermophoretic coagulation. Based on the analytical solution, the characteristics of the size distribution evolution during thermophoretic coagulation are investigated theoretically. The results show that the coagulation process is faster with a larger initial Geometric Standard Deviation and the time required to reach the self-preserving distribution increases with the difference between the initial and asymptotic Geometric Standard Deviations.

T B L Kirkwood - One of the best experts on this subject based on the ideXlab platform.

  • Geometric Standard Deviation reply to bohidar
    Drug Development and Industrial Pharmacy, 1993
    Co-Authors: T B L Kirkwood
    Abstract:

    AbstractBohidar (1) comments that a formula I proposed (2) for Geometric Standard Deviation (GSD) is “absolutely incorrect”. This comment is based on erroneous interpretation of my proposal and to avoid further confusion it may be helpful to point this out. The issue addressed in ref(2) was how to summarize the extent of statistical variation in a sample of data drawn from the lognormal distribution, for which the underlying variation is multiplicative. This situation was contrasted with the normal, or Gaussian, distribution for which the underlying variation is additive. Normally distributed data are conveniently summarized by a mean plus or minus a Standard Deviation (SD) (or Standard error, SE). For lognormal data the Geometric mean was available as replacement for the ordinary mean, but no direct analogue existed for SD (or SE).

N R Bohidar - One of the best experts on this subject based on the ideXlab platform.

  • determination of Geometric Standard Deviation for dissolution
    Drug Development and Industrial Pharmacy, 1991
    Co-Authors: N R Bohidar
    Abstract:

    AbstractThe two important instances in which the scientist converts his/her experimental data to a logarithmic scale prior to computing the mean and Standard Deviation, are (i) when the distribution of the data is asymmetrical (e.g. percentage data) and (ii) when he/she intends to compare statistically the averages of two or more groups with unequal Standard Deviations. In either case, the mean is restored to its original scale by taking the antilog of the log mean, which is the Geometric mean. However, this procedure cannot be applied for computing the Geometric Standard Deviation. The author of reference(l) erroneously claims that the antilog of log Standard Deviation is the Geometric Standard Deviation. This paper demonstrates the incorrectness of the procedure in reference (1), exhibits the exact statistical formula and introduces a novel method called “jackknife statistic” to confirm the results, based on the dissolution data associated with Product-C.