Concept and Characteristics of Powder Formulations

Concept

Powder formulations are dry powder preparations made from raw medicinal substances or suitable excipients that have been crushed and uniformly mixed. Powder formulations can be divided into oral powders and topical powders. Oral powders are generally dissolved or dispersed in water, diluents, or other liquids for consumption, or can be taken directly with water. Topical powders can be applied to the skin, oral cavity, throat, or other cavities. Depending on the intended use of the powder, the particle size requirements vary; oral powders are fine powders, meaning they pass through a No. 5 sieve, with ≥95% passing through a No. 6 sieve (100 mesh); pediatric and topical medications require the finest powders, meaning they pass through a No. 6 sieve, with ≥95% passing through a No. 7 sieve (120 mesh); and ophthalmic powders are extremely fine powders, meaning they pass through a No. 9 sieve (200 mesh).

Characteristics

(1)High degree of pulverization, small particle size, large specific surface area, easy dispersion, convenient absorption, and rapid efficacy.

(2)Large coverage area for external use, providing protective and astringent effects.

(3)Simple preparation process, easy dosage control, convenient for infants and the elderly to take.

(4)Convenient for storage, transportation, carrying, and packaging. However, due to the high dispersion of powders, they are often significantly affected by properties such as hygroscopicity, chemical reactivity, odor, irritability, and volatility; therefore, drugs that are sensitive to light, moisture, and heat are generally not suitable for powder formulation.