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In addition to the test sample, the main factors affecting the dissolution test results are the mechanical properties of the dissolution instrument, the standard degree of the experiment personnel's operation and the reagents.
First, the shaking of the stirring rotating device
Whether it is the basket method or the paddle method, the fluid flow movement of the medium under the action of stirring forms the fluid shear force through the solid. The shaking of the paddle or the basket shaft will change the fluid dynamic properties of the medium, thus affecting the dissolution rate. Therefore, the shaking of the basket or paddle will change the dissolution rate of the preparation. The 2015 edition of Chinese Pharmacopoeia has clear requirements on the shaking of the stirring device, which generally stipulates that the oscillation amplitude shall not deviate from the axis by 1.0mm.
Center position of mixer
According to the general Rule 0931 of the 2015 edition of Chinese Pharmacopoeia, "the deviation between the rotation axis of the stirring shaft and the vertical axis of the dissolving cup at any point shall not be greater than 2mm", which is consistent with the requirements after coordination with PDG. Studies show that when the rotation axis deviates from the central axis of the dissolution cup by 2 ~ 6mm, the dissolution rate may be significantly increased by 2% ~ 10%.
Mixing speed
The rotation of the stirring device in the basket or paddle method produces the dynamic properties of the fluid and ultimately changes the liquid-solid interface state between the medium and the preparation. The state of the rotating shaft is the fundamental factor affecting the dissolution characteristics of the basket or paddle method. The accuracy and stability of rotational speed are the basic performance requirements of the stripping instrument. According to the 2015 edition of Chinese Pharmacopoeia, the rotational speed should be within the range of ± 4% of the rotational speed, which is consistent with the international requirements after coordination.
Dissolve the gas in the medium
The 2015 edition of Chinese Pharmacopoeia requires that, unless otherwise specified, the dissolution medium must be degassed, because at any given pressure and temperature, there is always a part of the gas dissolved in the liquid, and the presence of this gas may affect the reproducibility of the results during the dissolution test. The prednisone tablets used in the United States Pharmacopeia for performance verification are samples that are particularly sensitive to the gas content in the medium.
Temperature
The effect of temperature fluctuations depends on the temperature-solubility curves of active ingredients and adhesives and other excipients. In general, solubility and temperature have a linear relationship. Different preparations may have different sensitivities to the same temperature change. Studies have shown that every 1℃ temperature change can cause a change in dissolution rate of up to 5%.
According to the 2015 edition of Chinese Pharmacopoeia, the temperature of the dissolution medium is 37 ° C ±0.5 ° C. When used for transdermal patch, the temperature of the dissolution medium is 32 ° C ±0.5 ° C. The temperature of the dissolving medium in the dissolving cup should be within the specified range and sufficient equilibrium time should be guaranteed.
Sampling position
Foreign pharmacopoeia from the absorption of dissolution, sampling position has not changed, that is, "from the inner wall of the dissolution cup is not less than 10mm". According to the 2015 edition of Chinese Pharmacopoeia, the sampling side will affect the determination of the dissolution amount, especially in the initial stage of dissolution, and the specific sampling position can be more conducive to the reproducibility of the results.
Adsorption
Experience has shown that some specific materials used in dissolution meters or filters used for filtration may have very strong adsorption effects on the active ingredient. When verifying a new dissolution meter or test method, especially an automatic dissolution system, the adsorption of the active ingredient by the material should be considered and the appropriate material should be selected.
DS-812SAT dissolution tester is a high-performance 12-cup, 12-bar dissolution tester designed and manufactured in accordance with the requirements of 2015 edition of Chinese Pharmacopoeia, United States Pharmacopoeia and Guiding Principles for Mechanical Verification of Drug Dissolution Tester.
Main Features:
★ Meet the requirements of "Chinese Pharmacopoeia" and "United States Pharmacopoeia" and "Guiding Principles for mechanical Verification of Drug dissolution meter".
12 dissolving cups and 12 rods can be placed.
★ The driving head of the disintegrator adopts the intelligent automatic lifting mode. The imported electric lifting column ensures the accurate and reliable lifting of the disintegrator head, and ensures the repeatability of the experimental conditions of key parameters such as the setting height and center position of the stirring shaft.
High precision dissolving cup center positioning.
★ Use a non-resident high precision temperature probe to monitor the temperature of the dissolution medium at a preset time point, and configure an integrated sampling needle to ensure that the sampling position remains unchanged.
★ Adopt imported stepper motor to control the speed, to ensure the speed is accurate, stable and reliable.
★ A common rotating shaft can be connected to the interchange of the rotating basket and blade, height after the initial positioning, no need to readjust, switching is extremely convenient.
Color touch screen, with graphic display, easy and intuitive operation.
★ Through the large size of the touch screen can be convenient for user permission setting data tracking, to ensure that only allowed users can operate the instrument, fully in line with the USP/FDA and other regulations.
★ Automatic sampling system: 12 channel injection pump sampling, 180 bit sample collection device, automatic replenishment, automatic cleaning, sampling accuracy ±1%, with online filtration function.
