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P K Aldridge

Publications and source records attributed to P K Aldridge.

3 recordsLinked to original sources

Automated system for the on-line monitoring of powder blending processes using near-infrared spectroscopy. Part I. System development and control.

An automated system for the on-line monitoring of powder blending processes is described. The system employs near-infrared (NIR) spectroscopy using fibre-optics and a graphical user interface (GUI) developed in the LabVIEW environment. The complete supervisory control and data analysis (SCADA) software controls blender and spectrophotometer operation and performs statistical spectral data analysis in real time. A data analysis routine using standard deviation is described to demonstrate an approach to the real-time determination of blend homogeneity.

Chemistry, Pharmaceutical↗

A robotic dissolution system with on-line fiber-optic UV analysis.

An automated, robotic system has been developed with on-line UV fiber optics for real time dissolution analysis of solid dosage forms. The system is comprised of "off-the-shelf" hardware including a UV-Vis diode array spectrophotometer, fiber optic coupler, immersion probe, robot, and dissolution apparatus. The software system is modular with the functionalities of control, data acquisition, and spectral analysis separated into three Windows applications with communications performed via Dynamic Data Exchange (DDE). The fiber optic spectrophotometer collects a full spectrum over the range of 190-810 nm. Single wavelength UV analysis is performed on dosage forms in six dissolution vessels. The robotic system automates all facets of the analyses: measuring, degassing, and dispensing of the media; thermostating the media to physiologic temperature; dropping the dosage forms into the vessels; immersing the fiber optic probe at the appropriate time intervals; initiating the data acquisition, analyses, and reporting; and emptying and washing of the vessels prior to the next automated run. As a representative dosage form, 10 mg active tablets were selected and analyzed by this method. This fiber optic system has significantly improved the throughput of the robotic systems by eliminating the need for time consuming off-line HPLC or UV analyses. In addition, with the exception of system calibration, it is no longer necessary for laboratory personnel to come in contact with samples.

Chemistry, Pharmaceutical↗

Observation of individual DNA molecules undergoing gel electrophoresis.

Individual DNA molecules undergoing agarose gel electrophoresis were viewed with the aid of a fluorescence microscope. Molecular shape and orientation were studied in both steady and pulsed electric fields. It was observed that (i) DNA macromolecules advanced lengthwise through the gel in an extended configuration, (ii) the molecules alternately contracted and lengthened as they moved, (iii) the molecules often became hooked around obstacles in a U-shape for extended periods, and (iv) the molecules displayed elasticity as they extended from both ends at once. A computer model has been developed that simulates the migration of the molecules in a rotating-field gel electrophoresis experiment.

Computer Simulation↗