Drug stability test boxCalibration ofIt is necessary to focus on core parameters such as temperature, humidity, light intensity, and radiation intensity, and ensure that equipment performance meets regulatory requirements through standard instrument comparison, multi-point measurement, and environmental control. The following are the key steps and points of calibration:
1、 Preparation before calibration
Environmental condition control
Temperature: 15 ℃~35 ℃ (some specifications require 5 ℃~30 ℃), avoid interference from heat sources or vibration sources.
Humidity: ≤ 85% RH, keep away from corrosive gases and strong electromagnetic fields.
Power supply: Stable voltage (such as 220V ± 22V), reliable grounding.
Equipment inspection
Confirm that there are no defects in the appearance of the test chamber, and that the mechanical and electrical parts are working properly.
Check if the positions of temperature and humidity sensors, as well as light/radiation sensors, are reasonable to ensure proper air circulation.
Preparation of standard instruments
Temperature: Use a four wire platinum resistance thermometer with a resolution of ≥ 0.01 ℃ and a maximum allowable error of ± 0.15 ℃.
Humidity: The hygrometer has a resolution of 0.1%, an accuracy of 2%, and covers the humidity range of the test chamber (such as 10%~90% RH).
Illuminance: A first level illuminance meter (compliant with JJG245), with a measurement range covering the nominal value of the test chamber (such as 10-10000 lx).
Radiant illuminance: UV radiometer (compliant with JJG879), wavelength range 320nm~400nm.
2、 Core parameter calibration method
1. Temperature calibration
Steps:
Set the temperature of the test chamber to the commonly used test points (such as 25 ℃, 40 ℃) and stabilize for 2 hours.
Uniformly distribute the standard thermometer probes in the workspace (such as the five point method: center and four corners).
Record the temperature at each point, calculate the deviation (difference between the displayed value in the test chamber and the standard value) and uniformity (maximum temperature difference).
requirements
Temperature deviation: within ± 2.0 ℃ (long-term test) or ± 0.5 ℃ (accelerated test).
Temperature fluctuation: ≤± 0.5 ℃ (the difference between the maximum and minimum values within 24 hours).
2. Humidity calibration
Steps:
Set the humidity to the commonly used test points (such as 60% RH, 75% RH) and stabilize for 1 hour.
Place the standard hygrometer near the sensor and record the humidity value.
Repeat the measurement three times and take the average to calculate the deviation.
requirements
Humidity deviation: within ± 5% RH, fluctuation ≤ ± 2% RH.
3. Illuminance calibration
Steps:
Set the illuminance to the commonly used value (such as 4500lx) and stabilize for 30 minutes.
Place the standard illuminance meter detector at the center and corners of the sample rack (five point method).
Record the illuminance at each point and calculate the uniformity (the ratio of the minimum value to the maximum value).
requirements
Illuminance error: ≤± 500lx (4500lx calibration point).
Uniformity: ≥ 80% (i.e. minimum/maximum value ≥ 0.8).
4. Radiance calibration (for UV test chambers)
Steps:
Set the radiation illuminance to the commonly used value (such as 80-100 μ W/cm ²) and stabilize for 30 minutes.
Measure the radiation values at the center and corners of the sample holder using a standard radiometer.
Calculate the relative indication error or correction factor.
requirements
Radiation illumination error: ≤± 10% (wavelength range 320nm~400nm).
3、 Calibration result processing
Data recording:
Record the calibration points, standard values, displayed values, deviations, and uncertainties of each parameter.
Result judgment
Determine whether the deviation is within the allowable range according to pharmacopoeia or standards (such as JJF (Wan) 150-2023).
If it exceeds the tolerance, it is necessary to adjust the equipment parameters (such as PID control parameters) or contact the manufacturer for maintenance.
Certificate issuance:
The calibration certificate should include equipment information, calibration conditions, standard instrument information, calibration results, and conclusions.
Suggestion for the resumption period: generally not exceeding 1 year, or shortened according to the frequency of use.
4Drug stability test boxCalibration ofPrecautions
Safe operation:
Avoid covering the ventilation openings of the equipment to prevent overheating and fire hazards.
It is prohibited to place flammable and explosive materials inside the equipment.
Maintenance and upkeep:
Regularly clean sensors and ventilation openings, and replace humidification water (distilled or deionized water is required).
Check if the functions of over temperature protection, leakage protection, etc. are normal.
Deviation analysis:
If the calibration results are abnormal, it is necessary to analyze the reasons (such as sensor aging, environmental interference) and take corrective measures.