Oral Solid Dosage Forms
Basic Performance Requirements: Excipients must exhibit low hygroscopicity and low moisture content, along with excellent compactibility to ensure the final dosage form meets friability standards. They must also be physiologically inert, showing no chemical reactivity with the active pharmaceutical ingredient (API).
Requirements for Specific Dosage Forms:
Conventional Tablets: Require compatible disintegrants and lubricants to ensure rapid tablet disintegration and prevent sticking to punches or dies during manufacturing.
Orally Disintegrating Tablets (ODTs) / Chewable Tablets: Excipients must offer a pleasant mouthfeel without any grittiness; fillers such as mannitol-which also serve to improve taste-are often preferred.
Sustained/Controlled-Release Preparations: Require specialized release-retarding agents or matrix materials to precisely control the drug release rate, ensuring stable plasma drug concentrations and avoiding "peak-and-trough" fluctuations.
Injectable Preparations
Core Safety Standards: All excipients must be sterile and pyrogen-free. Residual solvents and elemental impurities must be strictly controlled. In principle, bacteriostatic agents (preservatives) are prohibited in injections intended for intravenous or intraspinal administration.
Functional Requirements:
Osmolality and pH must be precisely adjusted to ensure the solution is physiologically compatible with human blood, thereby preventing hemolysis or vascular irritation.
For formulations containing surfactants or lipophilic excipients (e.g., liposomes, lipid emulsions), compatibility with infusion equipment and flexible packaging materials must be evaluated; leachables/extractables studies may also be required.
When solubilizers such as Polysorbate 80 are used in traditional Chinese medicine (TCM) injections, impurity levels must be strictly controlled to minimize the risk of allergic reactions.
