Principles of Operation
Samples (either ribbons or tablets) are scanned between dual opposed laser beams by a computer controlled translation stage in order to quickly (≈ 2 minutes) determine the sample volume, and then transferred to an internal Mettler balance to determine the sample mass. Together with the operator entered true density of the powder, the solid fraction is automatically calculated and displayed on the touch screen display.
Overview of System Operation
To initiate the solid fraction measurement of a sample, the operator uses the touch screen at the top of the enclosure to manually enter the Drug ID, Batch ID, and the true density of the pre-compacted powder particles. Upon clicking an on-screen button, the computer-controlled sample holder is automatically moved to the sample loading position, at which point the operator is prompted to install the sample pedestal. Once the pedestal is installed, the user clicks another on screen button to instruct the system to grasp the sample. After the sample has been gently grasped by the computer-controlled sample holder and the pedestal has been removed, the operator closes he door of the instrument and clicks an on-screen button to begin the measurement. At this point, the motion control and laser measurement system automatically begins an appropriate sequence of scans to determine the volume of the sample. At the completion of the volume measurement (which requires approximately 2 minutes), the sample is automatically transferred to the Mettler weighing module, where its mass is determined and recorded by the computer. Utilizing the operator entered value for the true density of the material, as well as the apparent density calculated from the measurements of mass and sample volume, the solid fraction is calculated and displayed on the screen, and a visual alert informs the operator of the completion of the measurement.
a. Minimum thickness = 1 mm
b. Maximum thickness = 8 mm
c. Minimum width = 5 mm
d. Maximum width = 20 mm
e. Minimum length = 11.4 mm
f. Maximum length = 100 mm
a. Minimum thickness = 1.25 mm
b. Maximum thickness = 10 mm
c. Minimum width = 3.18 mm
d. Maximum width = 20 mm
e. Minimum length = 6.4 mm
f. Maximum length = 30 mm
g. Minimum belly band height: 1mm
h. Minimum mass: 100mg
* Special versions are available to accommodate samples outside the above parameters.
The date and time of each measurement, together with the Drug ID, Batch (or Lot) ID, Group Number, measured sample volume, sample mass, operator entered density value and the calculated solid fractions (and associated averages) are stored to an Excel compatible data file for subsequent review and/or report generation. A data transfer option allows all accumulated data to be transferred to a USB Flash drive, so that the accumulated data can be archived and analyzed on any facility PC.
Group by group comparison of solid fraction within the same Batch ID
This capability is provided in several different forms:
1. The current group mean, batch mean, the sample solid fraction are displayed at the completion of each sample.
2. On-screen plots of solid fraction vs. group number at the end of the sample run: An on- screen graph of solid fraction (Y axis) vs. group number (X axis) is available to display all measurements for the same batch of the specified Drug ID. This tool allows the operator to quickly determine whether groups of samples from the same Drug ID and Batch ID show systematic differences (which may correlate with time of preparation, compactor settings etc.). This feature eliminates the need to transfer the data to a PC in order to assess these types of first order questions.
3. Offline Analysis of group segregated data in the summary results file: Given the presence of the group number in the variables stored for each sample, a variety of group related differences can now be examined by review and analysis of data within the Excel compatible results file. This could be used, for example, to compare solid fractions for a specific group number of each batch produced for a specific Drug ID, or to look at differences between the first and the last group of a batch of the same Drug ID.
The system can be supplied with a USB-based “label” printer to allow immediate printout of results, either at the completion of each sample, or at the end of any sample group. Printouts include the date and time of the printout, the Batch ID, the current operator name, the mass, volume, and solid fraction of each sample within the group, and the average solid fraction for all samples measured so far within the group.
Option to report results as porosities
Although the measurement system is formally referred to as a “solid fraction measurement system”, at the user’s option, it can be configured to report measurement results as porosities.
System validation capability
Ability to perform system validation checks utilizing certified samples whose solid fraction is known. In addition to the ability to fixture a wide variety of different tablets, the tablet sample holder has the ability to fixture a certified ceramic gage block, whose dimensions have been certified by an NIST traceable calibration laboratory.
Provision for system cleaning
The sides and the top of the instrument enclosure are designed to be easily and quickly removed to wipe down or otherwise remove dust from portions of the instrument housing which cannot be easily accessed through the front sample loading/sample removal door.
Remote, Internet-based diagnostic capability
The system can be supplied with an external Ethernet port so that, when desired, the customer’s IT staff can connect the system to the Internet to allow Solid Fraction Measurement System’s staff to remotely perform software upgrades including new system enhancements, as well as to help diagnose any potential system problem which might arise.