The pulverization of traditional Chinese medicine extract is a difficult task, especially for ultrafine pulverization with a fineness exceeding 120 mesh.

1traditional Chinese medicineExtract extractionThe main properties of the extract are: strong viscosity, strong moisture absorption, and strong heat sensitivity (low softening point). Specifically manifested as:

1) Viscosity:

This is the biggest challenge. The paste is usually very viscous. The finer the pulverization, the larger the specific surface area, and the more significant the viscosity performance, making it easy to adhere to equipment (such as glue machines and screens), agglomerate, and have extremely poor fluidity.Low temperature crushingIt is a commonly used and effective method to solve stickiness.

2) Moisture absorption:

Many extracts are prone to moisture absorption. After crushing, the surface area increases and moisture absorption is faster, which may lead to clumping. smashEnvironmental humidity controlAfter crushinghandle promptlyvery important.

3) Thermal sensitivity: (softening point/melting point):

Some components of the paste will soften or even melt under the heat generated by crushing, exacerbating its viscosity. Low temperature pulverization (such as liquid nitrogen cryogenic pulverization and pulverizers with cooling devices) is almost necessary for this type of paste.

4）水分：

The moisture content directly affects the viscosity and crushing difficulty. Usually, it is required to control the moisture content of the paste at a low level before crushing (such as3% -5% or lower，Specifically depending on the variety.

2、 Analysis of commonly used fineness ranges in current production:

160-80 mesh：

This is a very common range, mainly applicable to:

1) Pre treatment before granulation: Grind the extract into relatively coarse particles for easy mixing with excipients (such as dextrin and starch), and then perform wet granulation or dry granulation. This mesh size can ensure uniform mixing without causing excessive viscosity, poor flowability, or difficulty in granulation due to being too fine.

2) Direct compression (in some cases): For certain specific extracts and formulations, with appropriate excipients and processes, 60-80 mesh powder may also be used for direct compression, but this requires good flowability and strong compressibility of the extract powder.

280-100 mesh：

This range is more specific and applicable to:

1) Require more uniform granulation or direct compression: When the extract needs to be mixed with a large amount of excipients, or when there is a high requirement for uniformity of content, finer powder may be needed.

2) Filling capsules: Finer powders usually have better flowability, are easier to fill capsules, and have smaller differences in filling volume.

3) As an intermediate or active pharmaceutical ingredient: sometimes finely ground for storage, transportation, or as a raw material for other formulations.

3>100 mesh (such as 120 mesh or higher, 200 to 300 mesh or more)：

Relatively rare, mainly used for:

1) Special dosage form:

If ultrafine grinding is needed to prepare dispersible tablets, rapid release tablets, or special oral preparations.

2) Improve bioavailability (theoretically):

Finer powders may increase the dissolution surface area, but it is necessary to balance the negative effects of increased viscosity and moisture absorption.

3) External powder:

If the extract is used to prepare external powders, finer powders may be required.

3、 At presentThe crushing ability of various crushing equipment for the extract:

Different crushing equipment, such as universal crushers, turbine crushers, airflow crushers, and low-temperature crushing systems, can achieve different levels of fineness and have varying abilities to handle viscous materials. It is difficult for ordinary crushers to handle high viscosity powder that is too fine.

Beijing has pioneered the KC series ultra-low temperature ultrafine pulverizer from Tonghe, which adopts ultra-low temperature pulverization technology and key technical points to avoid clumping of paste. It can process high viscosity paste with a fineness of 200-300 mesh or even higher. For example, Angelica sinensis extract, Eucommia ulmoides salt extract, ginseng extract, etc. Among them, the fineness of ginseng extract is close to 5000 mesh, and the laser particle size detection report is for reference.

Starting point: 60-80 mesh is a commonly used and practical range for crushing traditional Chinese medicine extracts, especially suitable for pre-treatment before granulation. It can effectively control the operational difficulties caused by viscosity while ensuring a certain degree of mixing uniformity.

Process matching: The final selection must be closely integrated with the specific requirements of subsequent processes (granulation, tablet pressing, capsule filling).

Solving viscosity is the core: low-temperature crushing (cryogenic crushing) is a key technology for processing high viscosity, low softening point extracts to obtain finer powders (such as 80-100 mesh or even finer). Without low temperature conditions, pursuing high mesh numbers is often unrealistic.

Step by step crushing: Sometimes, the difficulty can be reduced by first coarse crushing (such as 20-40 mesh), and then mixing with some auxiliary materials for secondary crushing.

Auxiliary material adjustment: The number of crushing mesh also needs to consider the type and proportion of auxiliary materials added later. Full extract granulation and semi extract granulation may have different requirements for the fineness of the extract powder.

Experimental determination: A reliable method is to determine the optimal crushing mesh size through small-scale and pilot tests based on the specific characteristics of the extract, target dosage form, and process route of the variety.

(This article is original by Beijing Kaichuang Tonghe Technology Development Co., Ltd. Please indicate the source when reprinting! Infringement is prohibited!)