RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter UniPHY Group iResearch App Facebook

Review of Scientific Instruments / Volume 76 / Issue 3 / BIOLOGY AND MEDICINE

Rev. Sci. Instrum. 76, 034302 (2005); doi:10.1063/1.1863832 (7 pages)

Optical instrument for measurement of vaginal coating thickness by drug delivery formulations

Marcus H. Henderson1, Jennifer J. Peters1, David K. Walmer2, Grace M. Couchman2, and David F. Katz3

1Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708
2Department of Obstetrics and Gynecology, Duke University, Durham, North Carolina 27710
3Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 and Department of Obstetrics and Gynecology, Duke University, Durham, North Carolina 27710

View MapView Map

(Received 11 August 2004; accepted 10 January 2005; published online 1 March 2005)

An optical device has been developed for imaging the human vaginal epithelial surfaces, and quantitatively measuring distributions of coating thickness of drug delivery formulations—such as gels—applied for prophylaxis, contraception or therapy. The device consists of a rigid endoscope contained within a 27-mm-diam hollow, polished-transparent polycarbonate tube (150 mm long) with a hemispherical cap. Illumination is from a xenon arc. The device is inserted into, and remains stationary within the vagina. A custom gearing mechanism moves the endoscope relative to the tube, so that it views epithelial surfaces immediately apposing its outer surface (i.e., 150 mm long by 360° azimuthal angle). Thus, with the tube fixed relative to the vagina, the endoscope sites local regions at distinct and measurable locations that span the vaginal epithelium. The returning light path is split between a video camera and photomultiplier. Excitation and emission filters in the light path enable measurement of fluorescence of the sited region. Thus, the instrument captures video images simultaneously with photometric measurement of fluorescence of each video field [ ∼ 10 mm diameter; formulations are labeled with 0.1% w/w United States Pharmacoepia (USP) injectable sodium fluorescein]. Position, time and fluorescence measurements are continuously displayed (on video) and recorded (to a computer database). The photomultiplier output is digitized to quantify fluorescence of the endoscope field of view. Quantification of the thickness of formulation coating of a surface sited by the device is achieved due to the linear relationship between thickness and fluorescence intensity for biologically relevant thin layers (of the order of 0.5 mm). Summary measures of coating have been developed, focusing upon extent, location and uniformity. The device has begun to be applied in human studies of model formulations for prophylaxis against infection with HIV and other sexually transmitted pathogens.

© 2005 American Institute of Physics

Article Outline

  1. INTRODUCTION
  2. SYSTEM DESCRIPTION
    1. Device design and imaging methodology
      1. Device design
      2. Use of a fluorescein label and instrument calibration
      3. Mechanical configuration of the entire instrument
    2. Calculation of local coating thickness
      1. Background subtraction: Corrections for tissue autofluorescence and reflectance
      2. Error analysis
      3. Measures of formulation distribution
  3. PILOT APPLICATIONS IN WOMEN
  4. DISCUSSION

RELATED DATABASES

To view database links for this article, you need to log in.

KEYWORDS and PACS

Keywords

endoscopes, biomedical optical imaging, drug delivery systems, biomedical measurement, photometry, bioluminescence, thickness measurement

PACS

  • 87.63.-d

    Non-ionizing radiation equipment and techniques

  • 87.80.-y

    Biophysical techniques (research methods)

  • 87.64.K-

    Spectroscopy

  • 07.60.Dq

    Photometers, radiometers, and colorimeters

  • 87.50.wj

    Dosimetry/exposure assessment

  • 06.30.Bp

    Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

  • 87.63.L-

    Visual imaging

ARTICLE DATA

Permalink
http://link.aip.org/link/doi/10.1063/1.1863832

PUBLICATION DATA

ISSN:

0034-6748 (print)  
1089-7623 (online)

Publisher:

$abstract.society.value is a Member of CrossRef American Institute of Physics

For access to fully linked references, you need to log in.

For access to citing articles, you need to log in.


Figures (3) Tables (1)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)



Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Optical instrument for measurement of vaginal coating thickness by drug delivery formulations
  2. Development of the third generation electron cyclotron resonance ion source
Go to AIP Home
Copyright © American Institute of Physics
close