The spray drying technology uses a spray method to disperse the material in a hot air stream in a mist state. The material is in full contact with the hot gas to complete the heat transfer and mass transfer process in an instant, so that the solvent (including water and organic solvent) evaporates rapidly. For gas, achieve the purpose of drying. Spray drying technology is widely used in the pharmaceutical industry in China. It is widely used in the field of oral solid preparations, and is often used for the drying of easily decomposable drugs in high heat sensitive medicines and liquid concentrates. The obtained product has fine particle size, uniformity, good fluidity and fast solubility.
Process requirements for oral bulk drugs: There are many kinds of oral solid preparations, and the specific process requirements are also very different. In the process of designing and manufacturing spray dryers, Zui has different designs for different varieties to achieve the ideal equipment and process. status. Solid formulation production When using a spray dryer, some of the requirements listed below are often raised:
1. Cleanliness requires the main process of API production to be carried out in a 100,000-level clean environment. Spray drying is an important process for quality control. The part of the spray dryer that contacts the material should be made of stainless steel. For materials with strong acid corrosion, choose 316L stainless steel. Drying chamber, cyclone separator, filter and other parts that directly contact the material should have smooth inner wall, no dead angle, easy to clean, easy to disassemble, and easy to clean. Spray dryers tend to be bulky, so they cannot be placed in a clean area as a whole, and often only the part where the material is collected is placed in a clean area. This requires a good system sealing performance to prevent external contamination from being systematic.
2. Avoiding sticky wall sticking is still a prominent problem that hinders the normal operation of spray dryers. The spray drying process of solid preparations (especially Chinese medicines) is particularly obvious. The sticky wall of the material is not only unfavorable for the collection operation, but as time goes on, the sensitive sticky wall material will deteriorate and become a non-conforming material. From a process point of view, the solution includes selecting the right solvent, adding the excipients, and changing the process parameters. However, there is not much room for adjustment of these methods, so a fundamental solution must be sought from the perspective of the equipment. Experts at home and abroad have conducted in-depth research on the problem of sticking and agglomeration in the drying process. It is agreed that the main cause of sticking is the wall temperature.
Here are five possible ways to prevent sticking:
1. Use a wall drying tower with air cooling to keep the wall temperature below 50 °C;
2. Introducing a secondary air cooling tower wall through the tangential direction of the tower wall cyclone;
3. Install an air broom consisting of a row of nozzles near the wall of the tower and slowly rotate it along the tower wall;
4. Increase the air hammer on the tower wall, and force the sticky material to be detached by the hammering of the air hammer;
5. Increase the precision of processing, and the inner wall polishing of the tower can also reduce the sticking wall.
3. Self-control performance Spray drying is a continuous production process with more control points. For example, the control points of the closed circulation system include: feed concentration, feed rate, inlet speed, inlet air temperature, system pressure, differential pressure of each component, gas purity detection, etc., relying on traditional manual adjustment is very difficult. A good automatic control system can make the whole spray drying system run smoothly, reduce the product's unqualified rate and reduce safety hazards. At present, domestic products are relatively backward in terms of self-control, while some advanced equipments in foreign countries, such as the spray dryers of Danish Nero Company, are already very mature in terms of self-control.
4. Drying effect Because the oral drug substance needs to further complete the preparation process, different requirements are imposed on the physical properties of the spray-dried product in terms of improving the effect of the preparation and the absorption effect of the final drug. First of all, the moisture content is the * indicator of the dry product, generally required to be controlled within a certain range, not too high or too low. Secondly, the dispensing of drugs generally controls the volume according to the volume, which requires that the bulk density of the product is stable and the fluidity of the product is good. Oral granules often require fast solubility. In general, by varying the dispersion of the atomization or by appropriately changing the operating conditions to control the drying rate, products having different bulk densities can be produced, but the magnitude of the variation is limited. One technique worth mentioning in improving physical properties is foam spray drying, in which the feed liquid is first foamed and then spray dried. This method was originally proposed to improve the thermal efficiency, and was later used to adjust the physical properties of the product. It has been proved that the product prepared by foam spray drying has large particle size, is porous, has many depressions, has a rough surface, and has good fast solubility. In addition, there are some special requirements for oral drug substances, such as: particle shape. Some require spherical particles with a uniform particle size. Generally, particles of different shapes can be obtained by changing the atomization method. Before selecting the spray dryer, the raw material drug manufacturer, with the assistance of the equipment manufacturing company, conducted parameter optimization experiments to determine an ideal combination of parameters to ensure the drying effect of the sprayed medicine.
V. Protection measures Due to the different nature of the drugs, some higher requirements are also placed on the protection design of the equipment. Materials dissolved in organic solvents require that the entire system must meet explosion protection requirements when dry. Explosion-proof type should be selected when designing motors, instruments, control valves and other accessories. In addition, in order to prevent the solvent and air from mixing into an explosive gas, the system cannot adopt an open type, but a closed circulation system must be used, and the carrier should be an inert gas such as nitrogen. In addition, some of the easy-to-oxide materials are dried, and a closed circulation system using nitrogen as a carrier is also used.
6. Environmental protection Spray-dried products are fine particles. In order to meet the requirements of environmental protection, it is not enough to use a cyclone separator to separate products and purify exhaust gas. It is generally necessary to purify with a bag filter to make it in the exhaust gas. The dust content is less than 50mg/(nm)3 gas; or the wet scrubber can reduce the dust content of the exhaust gas to 15~35mg/(nm)3 gas. When using nitrogen as the carrier, the system should be sealed and the exhaust port should be led to the outside.
7. Reduced cost The hot air inlet temperature is 250~500°C in cocurrent operation and 200~300°C in countercurrent operation. The outlet temperature after atomization drying is generally controlled at 60~100°C. The heat utilization rate of spray drying is low, and the industrial scale spray dryer generally has a thermal efficiency of 30% to 50%. Spray drying with waste heat recovery abroad can achieve a thermal efficiency of 70%, but this equipment is only economically meaningful when the production capacity is greater than 100kg (water) / h. However, when a nitrogen carrier and an organic solvent are used, a closed circulation system can be used, and the nitrogen can be recycled, and the solvent can be condensed, thereby effectively reducing the production cost.
Changzhou Zhiyang Machinery Equipment Co., Ltd. is a large-scale company that produces solid preparation equipment. Our company constantly improves the technical level in the production of spray drying equipment, solves the technical problems of spray drying in the field of oral raw materials, and hopes that the customers will find practical problems in the process of using the equipment. In time, we must respond, let our equipment Do your best. I believe that in the near future, we will be able to produce more suitable, high quality and low price products, so that our country's spray drying technology will reach the world's high level.
Granule Spreader
Specs:
Can withstand the sowing of seeds, fertilizers, bait and other solid particles
discharge valve can be adjusted
The speed of the turntable is adjustable
You can precisely control the amount and speed of download
Granule Spreader,Seed Sprayer,Agriculture Helicopter,Agriculture Plane,agriculture drone sprayer,drone agriculture sprayer,drone agriculture,agriculture spraying drone,agricultural fumigation drone,drone for agricultural spraying
Dongying Youjia Industry & Trade Co. Ltd. , https://www.uav55.com