Study on technology of fluidized bed spray granulation for solid preparation

Abstract: The solid preparation fluidized bed spray granulation process technology has many advantages, but there are some shortcomings and drawbacks in the practice. This technology requires us to rationally select pharmaceutical materials, control the inlet air temperature and humidity, atomizing air pressure, binder flow rate, air volume, and adjust the position of the tuyères. Only in this way will the pharmaceutical process be smoother and the drugs produced will be more standard.

1 Advantages of solid preparation fluidized bed spray granulation process technology

This technique many processes during granulation in the same equipment - a fluid bed is completed in the same time, reducing the cumbersome process, saving time, meet the requirements of GMP, no dust. Moreover, the pharmaceutical granules completed under the technology have the advantages of uniform size, round shape, good fluidity and good compressibility compared with the granules manufactured by other processes.

2 Disadvantages of fluidized bed granulation and its influencing factors

2.1 Material selection is difficult

The choice of granulating materials is the * step of our pharmaceutical process, but this step is not as easy as imagined. The particle size of the material , the choice of binder and the difference in density of the Chinese medicine extract powder and the excipients are all in progress. Factors that should be considered when selecting materials. If one or two of the conditions are not met and no solution can be found, our pharmaceutical process will be affected .

2.2 Control of inlet air temperature and humidity

Appropriate inlet air temperature and humidity are important factors for smooth pharmaceuticals. Temperature (wet) is too high or too low will affect the color and size of the drug . Therefore, we must control the intake air temperature (wet) degrees. The high inlet air temperature and rapid evaporation of the solvent reduce the ability of the binder to wet and penetrate the powder. Too low a temperature makes it difficult to dry wet particles and form larger agglomerates. If the humidity of the inlet air is too large, the wet particles cannot be dried in time, and a large amount of agglomeration will occur; if the inlet air humidity is too small, the dry particles cannot be wetted in time, and the next step cannot be performed.

2.3 Atomizing air pressure

Our aim is to produce granules that meet the standards in terms of specifications and quality . The specifications are mainly for size, and the granulation is mainly for the degree of hardness. The atomizing air pressure, which seems to be unrelated to the drug particles, is inextricably linked to whether the drug particles meet the standards. The size of the atomizing air pressure affects the size of the drug particles. The larger the atomizing air pressure, the smaller the droplets and the smaller the drug particles; the smaller the atomizing air pressure, the larger the droplets and the larger the particles. However, too large droplets will directly look at the uneven distribution of droplets, and there will be large wet blocks in the local range, which seriously affects the quality of the pellets.

2.4 Air volume

In fluidized bed equipment, there is a constant flow of air. However, the amount of air volume affects the speed and quality of the pellets. Of course, in the high-temperature fluidized bed equipment, if the air volume is large, the material is in a boiling state, the heat exchange is fast, and the drying is fast, which is favorable for granulation. However, if the air volume is too large, in the case of extremely fast heat exchange, the drying speed is fast, but as the "windy sand in the northwest is much more", a large amount of dust is generated in the fluidized bed equipment, which affects the progress of the pharmaceutical industry.

2.5 nozzle position

The nozzle, we can think of it as the "nozzle" of the fountain . If the nozzle position of the fountain is high, the flow rate of the single injection water is small; if the nozzle position of the fountain is low, the flow rate of the single injection water is sure to be large. According to the analogy method, we can know that if the nozzle is close to the fluidized powder, the particle diameter is large; away from the fluidized powder, the particle diameter is small. Therefore, we should choose a suitable location that should make the spray area as large as the wet bed surface area.

3 solutions

3.1 Choosing the right powder

Solid preparations fluidized bed spray granulation process is a technique using the airflow suspension was boiling like the powder material, and then injected into the atomized powder binding adhesive granulation. The misty binder is to be combined with the powder, and therefore, the powder should have wet water and adhesion and be easy to flow. However, it should have a degree of wet water, adhesion and fluidity. When this degree is not met, we can take some adjustments. For example, when the viscosity is too low, the outlet air temperature should be appropriately lowered.

3.2 Adjusting the air temperature

Each product has a wind temperature that suits you. Practice is one of a variety of products we test the air temperature is a powerful tool. Therefore, for the product, we should continue to practice to get the right wind temperature. However, there is a general rule in the wind temperature, too high temperature will accelerate evaporation and form a hard shell. So, we can take an adjustment approach. It is advisable to take a lower inlet air temperature and then increase the inlet air temperature after drying for a certain period of time.

3.3 Control the air volume

The amount of air volume should be determined according to the size of the binder moisture. If the moisture content of the binder is large, a larger wind temperature should be selected; if the moisture content of the binder is small, a smaller wind temperature should be selected. Through continuous practice, we have summarized the following experience: In the actual production, the granulation of the extract preparations is generally suitable for controlling the air volume at 4-6 m 3 /h during the drying process of the materials .

3.4 Control the flow rate of the adhesive

Controlling the flow rate of the binder is a difficult process, but there are still rules: when we want to make larger particles, we should take a larger flow rate of the binder; when we want to make smaller particles, we should take Small flow rate. However, this process requires a certain amount of technical content and should be strengthened.

3.5 The nozzle should be placed in the correct position

Due to the special position of the nozzle, the height of the nozzle is related to the particle size distribution of the particles. The distance of the nozzle is related to the size of the particles. Therefore, the height of the nozzle should be properly controlled, and if it is not properly controlled, it will affect the size of the particles.

4 Conclusion

The solid preparation fluidized bed spray granulation process technology has great advantages and is worthy of widespread promotion in the Chinese market, but this technology should attract attention in many places. On the one hand, we should increase investment in science and technology, increase the technical content in relevant areas, and strive to achieve certain process automation. On the other hand, it should be a lot of practice, through practice, summed up a given law, to serve the practice.