Xiaohua Zhang, Chunxia Yang, Ping Wang, Ping Yang, Shanru Liu, Shubin Liu & Xiaoling Yang
Abstract
Codonopsis-derived triterpenoid saponins merit investigation because preclinical studies identify immunomodulatory activity and a biologically active parent-metabolite relationship. Pulmonary delivery could increase exposure at a lung target while limiting unnecessary systemic exposure, but uncertain immune direction, membrane interactions, pulmonary absorption, and repeated-dose safety prevent a direct formulation recommendation. This critical narrative review evaluates chemical identity, lung pharmacology, and transferable delivery precedents using targeted searches updated through September 16, 2026 and a structured assessment of study relevance and limitations. Evidence is distinguished by material and route: defined saponins or fractions, composition-characterized botanical extracts, the associated metabolite echinocystic acid, and unrelated engineering precedents. Earlier anti-inflammatory lancemaside A studies and a 2026 immunostimulatory study in interferon-gamma-primed macrophages require matched replication rather than a claim of an established biphasic mechanism. Oral C. lanceolata extract efficacy in allergic lung inflammation and echinocystic acid pharmacology support further investigation but do not validate an inhaled parent saponin. No qualifying therapeutic aerosol-inhalation study of a Codonopsis saponin, standardized saponin fraction, or composition-characterized extract was identified in the searches performed. We propose four connected development stages: select a reproducibly beneficial active entity; establish pulmonary safety and local pharmacokinetics/pharmacodynamics with the simplest feasible formulation; correct a demonstrated delivery limitation when necessary; and integrate efficacy, device-patient suitability, storage stability, and manufacturing. Lipid carriers, spray-dried or spray-freeze-dried powders, mucus-modifying surfaces, and targeting systems are assessed against their measured benefits and failure modes. Numerical targets remain explicit development hypotheses rather than regulatory standards. The framework supports local pulmonary treatment as the initial objective and makes progression, reformulation, and termination conditional on evidence.
Keywords:
Codonopsis lanceolata, lancemaside A, echinocystic acid, Spray freeze-drying, triterpenoid saponins, pulmonary drug delivery, inhalation