The domestic market demand for medicine machines continues to grow, especially domestic equipment. Pharmaceutical freeze dryers are more and more popular because of their non-drying shrinkage, good rehydration, low water content, and long-term storage and transportation at room temperature after packaging. They are widely used in all aspects of the pharmaceutical industry.
Below, the editor will introduce the technical suggestions on the application scheme of pharmaceutical freeze dryers:
1. Drug preparation and pre-freezing:
In order to facilitate the formation of a stable porous structure after drying and freeze-drying, the drug solution must maintain a certain concentration. For hormones, enzymes, vaccines and other heat-sensitive drugs with relatively small doses, in order to increase the firmness of the freeze-dried product structure and the smooth appearance, Most require the addition of excipients.
For macromolecular biological protein drugs or slow-release drugs with biofilm structure, in order to prevent protein deformation or damage to the membrane structure during the freeze-drying process, it is necessary to add an appropriate freeze-drying protective agent.
The final temperature of drug prefreezing should be lower than the glass transition temperature Tg or eutectic temperature Te of the drug solution.
2. Main drying process:
The drying of medicines is a process from top to bottom and from outside to inside. The energy required for sublimation usually comes from the partition where the medicines are placed. Therefore, in the field of biopharmaceuticals, the separator of the pharmaceutical freeze dryer needs to have the function of temperature control.
The temperature setting of the separator often needs to rely on the knowledge and experience of the sample:
If the temperature control is too low, the heat provided by the separator is less than the energy required for sublimation, the sublimation rate decreases, the drying time is prolonged, and the energy consumption increases;
If the temperature control is too high, the heat provided by the separator is greater than the energy required for sublimation, and it is easy to cause the spray bottle or the bottom of the bottle to become empty.
The experimenter observes the freeze-drying curve measured during the freeze-drying experiment. If the following three points are satisfied, the temperature of the laminate can be appropriately increased to speed up the sublimation rate:
(1) The product temperature is 5°C lower than the eutectic point and disintegration temperature;
(2) The sample chamber pressure is 10%-30% of the saturated vapor pressure corresponding to the product temperature;
(3) The temperature of the cold trap is 20°C lower than the product temperature.
3. Analysis and drying:
Analytical drying, that is, secondary drying, is a process of removing about 10% of the remaining bound water in the product through higher temperature and lower pressure. During this process, the product temperature can be heated to a maximum allowable temperature that will not damage the product, usually as measured by product characterization and stability experiments.
During analysis and drying, since the water escaping from the product is less than that during sublimation, the water vapor captured by the cold trap decreases, so the temperature of the cold trap will decrease, and the decrease of the temperature of the cold trap will further increase the vacuum degree of the freeze-drying box. Generally, it should be Maintain this state for more than 2 to 3 hours, so that the residual moisture content in the product reaches the qualified requirements.
4. Packaging process:
Generally, the stopper/capping system is used in the freeze dryer to compress the half-stoppered bottle stopper; it can also be sealed and packaged after filling with nitrogen before stoppering.