Bioactivity-guided quality control of Shuxuetong injection: a critical narrative review of chemical profiling, candidate bioassays, and constituent-effect evidence

Shuxuetong injection (SXTI) is a multi-constituent animal-derived Chinese medicine injection used in clinical practice for thrombotic and ischemic disorders, often in combination regimens. Chemical identity and comparability do not by themselves establish comparable anticoagulant, platelet-related, fibrinolytic, or cellular responses across batches. This critical narrative review examines how chemical profiling can be connected to predefined biological endpoints for stepwise improvement of the SXTI quality standard. Literature identification and source verification were updated on 9 September 2026 using PubMed, publisher records, bibliographic metadata, and Chinese regulatory and pharmacopoeial sources. Evidence was distinguished by product matching and intended use. SXTI is governed by its registered product standard, not by a finished-product monograph in the Chinese Pharmacopoeia. A published 31-batch evaluative testing study reported no clear correlation between activity and content-assay results, providing direct support for investigating a complementary functional assay. Chemical studies describe multiple constituent classes and targeted peptide, nucleoside, and purine measurements, but these analytical counts are not interchangeable with a validated inventory of active ingredients. Thrombin-inhibition assays have direct SXTI reports and a crude- Hirudo pharmacopoeial precedent; neither establishes a transferable finished-injection release limit. Platelet, fibrinolytic, cellular, animal, and target-fishing methods remain principally supportive or developmental. Spectrum-effect analysis and affinity ultrafiltration-mass spectrometry (AUF-MS) can help prioritize constituents, whereas network pharmacology and docking generate hypotheses requiring functional confirmation. We propose retaining the statutory baseline while evaluating product-matched thrombin inhibition with defined controls, matrix tolerance, batch discrimination, cross-laboratory transfer, and a procedure for investigating out-of-specification results. Thrombin inhibition is therefore a priority for validation, not an immediately adoptable release specification or a surrogate for clinical efficacy and safety.