The equipment process of the melting time limit tester revolves around four core steps: sample preparation, temperature control, mechanical action, and data recording. Combining automation and manual operation, it ensures that the test results comply with pharmacopoeia or industry standards. The following are the specific process flow and key points:
1、 Fundamentals of Equipment Structure and Function
The melting time limit tester mainly consists of the following modules:
heating system
Electric heater: The core heating component heats the test material to the target temperature (such as 37 ℃± 0.5 ℃).
Thermocouple: Real time monitoring of temperature, feedback to the temperature controller, and precise temperature control achieved by adjusting the power of the electric heater.
Heating protection device: automatically cuts off power in case of abnormal conditions to prevent equipment damage.
Trial molding system
Squeezing head: Squeeze plastic pellets or suppository samples into the test mold tube.
Trial mold tube: accommodates the sample, and the mold core forms pores in the center to slow down the melting rate.
Lifting device: controls the up and down movement of the mold core and adjusts the size of the pores.
Timing system
Timer: Record the melting time of the sample.
Trigger: Detect the melting signal of the sample and start timing.
Signal amplifier: Amplify the trigger signal to the recognizable range of the electric heater.
Flip mechanism (some models)
Metal frame and hanging basket: Simulate the human environment (such as rectal temperature) through mechanical flipping to accelerate sample melting or dispersion.
Flip frequency: 30-32 times per minute to ensure uniform heating of the sample.
2、 Detailed explanation of process flow
1. Preparation before testing
Equipment inspection
Confirm that the power cord is securely plugged in and that there are no damages or stains on the surface of the device.
Check the completeness of accessories (such as sample holders, metal tweezers, cleaning brushes, etc.).
Insert the thermometer into the detection hole and observe whether the temperature on the display screen is consistent with the room temperature (if the temperature difference is greater than ± 2 ℃, calibration is required).
Sample preparation
Solid sample: Grind to a particle size of ≤ 2mm and evenly spread on a sample tray (thickness 3-5mm, leaving a 1cm gap at the edge).
Liquid sample: Allow to settle and defoam for 30 minutes before use.
Suppositories/vaginal tablets: placed directly on the lower disc of the metal frame and inserted into the sleeve.
Parameter Settings
Temperature: Pharmaceutical samples are usually set at 37 ℃± 0.5 ℃, and chemical materials refer to GB/T2918 standard.
Time: Regular testing for 30 minutes, special samples adjusted according to the company's internal control documents.
Flip mode: Select automatic or manual flip based on sample type.
2. Testing process
Start the device
Press the power button to wake up the control panel.
Turn on the circulating water pump and observe if the water flow indicator light flashes normally.
Place the sample
Place the sample tray horizontally on both hands and send it into the testing chamber. Confirm that the positioning buckle makes a "click" sound and the metal sealing ring is fully compressed.
Close the cabin door and check if the pressure gauge pointer is in the green area (the sample size needs to be adjusted in the red area).
Start testing
Press the test button, the device will automatically time and temperature control, and flip the metal frame according to the mode.
Double timer: manually start the stopwatch to prevent device timer failure.
real-time monitoring
Observe the display screen data every 5 minutes, focusing on temperature fluctuations (pharmaceutical equipment requires temperature control accuracy of ± 0.3 ℃).
Observe the morphological changes of the sample through the observation window, mark the starting point (the first phase transition of the liquid sample) and the ending point (complete loss of fluidity).
3. Testing completion and data processing
Stop testing
After the test is completed, the device will automatically sound an alarm prompt.
First, turn off the heating function and keep the water pump running for 10 minutes to cool down. Wait until the temperature drops below 40 ℃ before opening the cabin door.
Take out the sample
Use insulated clamps to hold the sample tray, and pour the remaining samples into the designated waste bin.
Suppositories/vaginal tablets need to be observed for melting, softening, or dispersion, and recorded for compliance with pharmacopoeia standards (such as complete melting of fatty matrix suppositories within 30 minutes).
data recording
Automatically print data strips and handwrite supplementary information in the experimental record book: environmental humidity, sample batch number, operator job number, equipment number.
Record abnormal situations (such as voltage fluctuations, sudden temperature changes).
3、 Key control points
temperature control
The heating system needs to ensure temperature uniformity and avoid local overheating that may cause sample decomposition or melting.
The pharmacopoeia requires a testing temperature of 37 ℃± 0.5 ℃ for suppositories, and specific standards should be followed for chemical material testing.
Sample uniformity
The particle size of solid samples and the thickness of the tray affect the melting rate, and it is necessary to strictly follow the standard operation.
Suppositories/vaginal tablets should be placed intact to avoid damage that could affect the results.
Mechanical action stability
The frequency of the flipping mechanism needs to be stable to prevent sample accumulation or uneven heating.
The lifting device controls the pore size of the mold core, which affects the determination of melting time.
data integrity
Double timing and manual marking ensure the accuracy of time recording.
Abnormal situations need to be recorded in detail to provide a basis for retesting or analysis.
4、 Application scenarios and standard basis
pharmaceutical industry
The melting time limit test of suppositories and vaginal tablets meets the requirements of the Chinese Pharmacopoeia (such as the melting of fat matrix suppositories within 30 minutes).
Ensure that drugs are released as expected in the human environment and exert their therapeutic effects.
Chemical and Materials Science
Plastic melting performance testing (such as melting temperature, time, index) to evaluate the application range of materials.
Quality control and product development, optimizing formulas or process parameters.
Research field
Research on material thermal stability provides data support for the development of new drugs or materials.