Final answer:
Suppositories and pessaries are prepared by hand molding, compression, or molding from melt, taking into account the displacement value for a correct dosage. Their evaluation involves verifying weight uniformity, drug content, melting range, and dissolution time.
Step-by-step explanation:
To discuss the method of preparation of suppositories and pessaries, including their displacement value and evaluation, it is important to understand that both dosage forms are designed for insertion into body cavities, where they melt, soften, or dissolve and exert local or systemic effects. Suppositories are typically used rectally while pessaries are inserted vaginally.
Some common methods of preparation include hand molding, compression, and molding from melt. Hand molding requires mixing the drug with a warmed base, shaping it by hand, and then cooling it. Compression involves compressing the drug and excipient into a mold, while molding from melt involves dissolving or suspending the drug in a melted base, pouring it into a mold, and then cooling to solidify.
The displacement value is critical in these preparations. It is the mass of excipient displaced by a unit mass of the active drug and affects the amount of base needed to produce suppositories of desired weight.
Evaluation of suppositories and pessaries includes tests for weight uniformity, drug content uniformity, melting range, and dissolution time to ensure consistent drug delivery.