Operation and Calibration of Tap Density Test Apparatus

1. Objective

             To lay down a procedure for Operation and Calibration of Tap Density Test Apparatus.

• Scope

This SOP is applicable to Operation and Calibration of Tap Density Test Apparatus (Make: Electrolab,  Model : Electrolab-ETD-1020) in Quality Control.  

•  Responsibility

QC Chemist / Officer            : Follow the procedure and maintain record as applicable.   

• Accountability

               Head Quality Control : System Compliance

•  Procedure:  
  • Operation:
    • Ensure that equipment is clean.
    • Check calibration due date.
    • Check the connection of electric supply.
    • Switch ON the power.
    • The instrument will initialize itself. The display will flash and show the start up screen
    • Using the digit scroll key, select the mode of operation as USP or USER.
    • Press the SET key to set the test parameters.
    • The test can be performed in two modes:
    • USP Mode :

The number of taps is as specified in the USP i.e. Tap Count 1-10, Tap Count 2 –500, Tap count 3-1250. The instrument will stop after every programmed tap count value and the validation report is available at the end of the test.

• User Mode: 

The number of taps is programmable from 1 to 9999 for ease of operation. It is useful for finding pilot readings of a product quickly. The instrument will stop after the set tap value. No validation report & the result screen available in this case

• Weigh approximately 100gm of the sample and transfer it to the 250ml measuring cylinder supplied along with the apparatus. If it is not possible to use 100gm, then amount of sample may be reduced and 100ml measuring cylinder supplied along with the apparatus may be used. Carefully level the test sample without compacting. Note down the apparent volume Vo  to the nearest graduated unit. (Fill the apparent volume greater than or equal to 60 % of the total volume of the cylinder unless otherwise specified).
  • Setting the method : 

This is a two station Tap density tester supporting both USP I & USP II methods of testing. The method for the test can be set as USP I or USP II, using the method key on the front panel.  This is the toggle key. When pressed the display will show the changed test method. METHOD indicator on the front panel indicates the selected method for the test. The unit allows any one test to be performed at a time. For 250ml cylinder, select USP I method and for 100ml cylinder select USP II method.

• USP I Method :

              In this method, the cylinder is raised and dropped under its own weight by a fixed drop    height of 14mm+ 2 mm at a nominal rate of 300 strokes/min. The cylinder should be tapped    for 10, 500, 1250 taps. .If the difference in volume between 500 and 1250 taps is less than    or equal to 2ml, then it is the final tapped volume. If the difference in volume between 500 and 1250 taps is greater than 2ml ,Repeat the test in increments of 1250 taps as needed until the difference between succeeding measurements is less than less than or equal to 2ml.

• USP II Method :

Same process except that a fixed drop height of 3mm + 0.2 mm at a nominal rate of 250 drops per minute.

• Tap Count Settings:
  • The value of Tap Count1 can be set from 1 to 9999 taps using the UP / DOWN & DIGIT SCROLL key. Press the enter key to go to the next parameter.
  • Tap count2 can be set from 1 to 9999 taps using the UP / DOWN & DIGIT SCROLL key. Press the enter key to go to the next parameter.

                  Note : Unless otherwise specified the following settings have to be entered :

                 Tap Count 1                                                   10 counts

                 Tap Count 2                                                   500 counts

                 Tap Count 3                                                  1250 counts

                Repeat in increments of 1250 taps as needed until the difference between succeeding  measurements is less than or equal to 2 ml.

• Press the start key to run the test.
  • Enter the weight of the sample
  • Enter the volume Vo using the UP/DOWN and digit scroll key.
  • Keep the measuring cylinder in the holder selected. Lock the holder assembly.
  • Press the START key.
  • After the programmed Tap count is over, measure the tapped volume Va to its nearest graduated unit. Enter the volume Va using the UP/DOWN and digit scroll key.
  • Press the START key. The test will continue till the programmed Tap Count2 is over. The display will now show the elapsed Tap and Drops per minute.
  • After the programmed Tap Count2 is over, measure the tapped volume Vb . Enter the volume Vb using the UP/DOWN and digit scroll key.
  • The difference between the two volumes Va & Vb is now calculated and displayed. If the difference is less than or equal to 2 ml then Vb is the final tapped volume Vf.
  • Pressing the stop key will display the results.
    • Tapped Density(T. Density)
    • Initial Density (Init. Den.)
    • Compressibility Index (Comp.Index )
    • Hausner Ratio
  • Connect the printer on-line to get the complete report of the test.
  • Pressing the SET key from the front panel will initialize the instrument for the new test.
  • After completion of test clean the equipment and accessories carefully.
  • Enter the details in Instrument log.
  • Note :
    • To halt the test, press stop key once. The test will stop and an option is displayed to either continue or abort the test.
    • Test print out of the last run can be taken by enabling the PRINT LAST RESULT? Y/N ( Option (f) in SET MENU) ( Set to Y & Press the ENTER Key).
    • If the power fails, when the test is going on, the remaining test can be completed when the power is resumed.
  • Important:
    • Avoid any dust gathering on the bearings.
    • Keep the shaft of the cylinder holder and the tip of the cylinder holder clean.
    • Place the cylinder in the holder only when the holder is place on the anvil.
    • If any problem exists inform to Engineering Department.
  • Calibration:
  • Procedure for Tap Counts:
    • Set the apparatus for 300 strokes (USP 1) / 250 strokes (USP 2).
    • Operate the apparatus and measure the time of 300 / 250 strokes using calibrated stop watch and record the time.  
    • Calculate the strokes / minute using the given below formula:

                                       Set Strokes   x 60  

                           = ————————————–

                                        Time Observed

• Record the observation.
  • Acceptance Criteria: ± 12 strokes.
  •  Procedure for height measurement :
    • Open the top cover by removing bottom screws.
    • Turn the cam attached to the motor shaft clockwise, so that the cylinder holder shaft is at the minimum position.
    • Make sure that the bottom plate of the cylinder holder is in perfect contact with the tapping platform.
    • Measure the distance between the platform and the clamp plate of cylinder holder with calibrated vernier and record as base height (H_R).
    • Rotate the cam further manually clockwise till the cylinder holder shaft reaches the maximum height.
    • At this position the shaft tip should be on the falling edge of the cam arm.
    • Measure the distance between the top plate of frame and the clamp plate of cylinder holder with calibrated vernier and record as height (H_I).
    • Make a mark on the point of measurement on the top plate of frame and on the cylinder plate.
    • The deference between these two readings (H_R & H_I) is the Drop Height of the cylinder.
    • Repeat the above procedure thrice for USP1 and USP2 methods and record the observations.
    • Acceptance Criteria:
    • Big Arm: 14±2 mm
    • small Arm: 3±0.2 mm
    • Prepare the calibration tag and affix it on the equipment.
    • Enclose the old calibration tag with the record and don’t throw it.  
    • If the variation is not within the specified tolerance limits:
    • Label the equipment with a tag, “OUT OF CALIBRATION”.
    • Inform the Department Head.
    • Do not use equipment until all errors are rectified. After rectification, again calibrate the equipment & record the observation.
    • Refer instruction manual for more details.
  •  Frequency :Three months ± 3 days
•  Annexure (S)

 Annexure-I     : Calibration Record of Tap Density Apparatus

•  Reference (S)

                  Manufacturer manual and USP

•  Glossary           

SOP               :  Standard Operating Procedure

QC                 :  Quality Control

QA                 :  Quality Assurance

USP               :  United states Pharmacopeia

•  Revision History

Rev. No.	Details of changes	Reason for change