The basic knowledge of medicinal desiccants

Desiccants are widely used in different fields, such as medicine, health care products, and diagnostic reagent industries. Medicinal desiccants require safety, environmental protection, non-toxic and harmless, as well as superior hygroscopicity and 100% biodegradability. Medicinal desiccants should obtain the “Pharmaceutical Packaging Material Registration Certificate” issued by the State Drug Administration.

What is a desiccant and what is its hygroscopic principle?
Desiccant is a kind of water remover that absorbs moisture from the atmosphere. Its drying principle is to physically absorb water molecules in its own structure or to chemically absorb water molecules and change its chemical structure. substance.

What are the main types of desiccants?
At present, there are three main types of desiccant products in the desiccant industry:
Silica gel desiccant---The main component is silicon dioxide, which is processed by natural minerals to be granular or beaded. As a little granules have a good affinity for water molecules. The most suitable moisture absorption environment for silica gel is room temperature (20 to 32) and high humidity (60 to 90%), which can reduce the relative humidity of the environment to about 40%.
Clay desiccant (montmorillonite) --- appearance of the shape of a gray ball, the most suitable moisture absorption in the environment below 50 °C. When the temperature is higher than 50°C, the degree of "release" of the clay is greater than the degree of "water absorption". But clay has the advantage of being cheap.
Molecular Sieve Desiccant --- It is a desiccant product that is synthetic and has strong adsorption to water molecules. The size of the pore size of the molecular sieve can be controlled by different processing techniques. In addition to adsorbing water vapor, it can also adsorb Other gases. At temperatures above 230°C, water molecules can still be well contained. Advantages: adaptable. Disadvantages: low moisture absorption, poor environmental protection (non-degradable).

How to determine the amount of desiccant?
The amount of desiccant depends on many factors: the size of the dry space, the properties of the packaging material, the storage environment of the packaged article, the atmospheric conditions during sealing, the shelf life of the packaged article, the degree of sealing of the package, and the like. When we design desiccant dosages for our customers, we need to know the above conditions before we can make the best answer.

What is saturation and what is balance capacity?
Although they are two concepts, for the desiccant, in practice it means that it is no longer hygroscopic. Saturation means that the desiccant has been saturated, and even if there is more moisture, it cannot be adsorbed.
Balanced capacity means that the desiccant has absorbed enough moisture from the air, so that the atmosphere's capacity for absorbing moisture exceeds the ability of the desiccant to absorb moisture. At this point, adding more desiccants will not reduce the relative humidity of the environment.

What does a unit desiccant mean?
Desiccant adsorption units commonly used abroad. According to the desiccant's adsorption capacity: a "unit" desiccant can adsorb 3.00g of water vapor at 25°C equilibrium temperature (RH=20%); a "unit" desiccant at 25°C equilibrium temperature Under the condition of (RH=40%), it can adsorb 6.00g of water vapor.

Specifically, a "unit" montmorillonite desiccant is equivalent to 33 grams, a "unit" silica gel desiccant and molecular sieve equivalent to 28 grams, and a "unit" fiber desiccant equivalent to 18 grams.

How to choose desiccant?
Medicines and health products, biological reagents, desiccants for the food industry. Dedicated desiccant characteristics: high hygiene requirements (industry license), packaging materials through the United States FDA demonstration. The product is compact and efficient, exquisite environmental protection, and has good compatibility and chemical stability.

According to the application environment, there are generally three cases: (MD type moisture absorption rate is 50% F type moisture absorption rate is 100%)
(1) Use in a small environment: The desiccant is placed directly in bottles, cans or other closed pouches to keep the items in the small environment dry.
(2) Use in a medium environment: The desiccant is used directly in a packaged carton (or drum or bag) to prevent the items in the package from getting wet.
(3) Use in a large environment: The desiccant is used directly in similar warehouses and containers to achieve the purpose of controlling the humidity in a large environment.