NOTE: This item is not available outside the Texas A&M University network. Texas A&M affiliated users who are off campus can access the item through NetID and password authentication or by using TAMU VPN. Non-affiliated individuals should request a copy through their local library's interlibrary loan service.
Frequency domain photon migration measurements: a method to size powders and detect active pharmaceutical ingredients in blending operations
MetadataShow full item record
Stringent rules and legal interpretations continuously encourage the pharmaceutical industry to innovate effective and practical methods to ensure the safety of its products to consumers. Most recently the final blending process in the fabrication of powder-based therapeutic products has come under scrutiny causing manufacturers to strive toward alternative solutions to their traditional validation methods. This thesis presents an optical technique, frequency domain photon migration (FDPM), as a means for process validation in the manufacture of solid pharmaceutics through its ability to characterize powder ingredients by particle size and ingredient composition. In this work, FDPM analysis techniques were utilized to extract particle size information in pharmaceutical powders. FDPM measurements were used to characterize a system of single component powders at various particle sizes. The results reveal a linear increase in the FDPM-measured scattering coefficient as the inverse mean particle size of the pharmaceutical powder increases. It was also observed that the scattering coefficient displayed no sensitivity to the wavelength of light at which the experiments were performed. In contrast, the FDPM-measured absorption coefficient exhibits light sensitivity; however, it appeared to be unaffected by changes in particle size of the powders. This initial study presents FDPM as a compelling tool for particle size analysis in pharmaceutical powders. Next, a system of dual-component powder mixtures, varying in excipient particle size and concentration of active pharmaceutical ingredient (API), was analyzed using FDPM techniques. The results show that the FDPM-measured absorption coefficient increased linearly with increasing API concentration while the isotropic scattering coefficient showed no sensitivity to changes in API concentration. It was further seen that the absorption coefficient of blends, owing to the API, was not only linearly dependent upon its concentration, but that this relationship was furthermore related to the excipient particle size. Finally, a comparison between near-infrared spectroscopy (NIRS) absorbance and FDPM-measured isotropic scattering as a function of reciprocal particle size was made to further highlight FDPM as a powerful particle sizing tool without need for calibration. Overall, this analysis presents FDPM as a comprehensive method for detection of API concentration independent of excipient particle size.
DescriptionDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to email@example.com, referencing the URI of the item.
Includes bibliographical references (leaves 67-70).
Issued also on microfiche from Lange Micrographics.
Torrance, Sharnay Etasha (2004). Frequency domain photon migration measurements: a method to size powders and detect active pharmaceutical ingredients in blending operations. Master's thesis, Texas A&M University. Available electronically from
Request Open Access
This item and its contents are restricted. If this is your thesis or dissertation, you can make it open-access. This will allow all visitors to view the contents of the thesis.