Targeting CAIX with [64Cu]XYIMSR-06 Small Molecular Radiotracer Enables Noninvasive PET Imaging of Malignant Glioma in U87 MG Tumor Cell Xenograft Mice

Synthesis and in vitro evaluation of radioiodine labeled hypoxia-targeted drugs containing 2-nitroimidazole and benzenesulfonamide groups

Designing new radiolabeled hypoxia-targeted drugs is of great help in the diagnosis of tumors. Hypoxia-targeted drugs with dual bioactive groups can enhance hypoxia selectivity, strengthen the binding of drugs to targets, and improve diagnostic accuracy compared with traditional hypoxia-targeted drugs containing only one nitroimidazole group. In this study, a series of novel radioiodine labeled tyrosine derivatives containing 2-nitroimidazole and benzenesulfonamide groups were synthesized and in vitro evaluated. In the uptake experiments of S180 cells that didn't express carbonic anhydrase IX (CAIX), the compound [131I]-3-(3-iodo-4-(2-(2-methoxyethoxy)ethoxy)phenyl)-2-(2-(2-nitro-1H-imidazole-1-yl)acetamido)-N-(2-(2-nitro-1H-imidazole-1-yl)ethyl)propenamide (131I-Tyr-05) containing two 2-nitroimidazole groups was modified from phenolic hydroxyl to methoxy to 2-(2-methoxyethoxy)ethoxy, gradually achieving improved membrane permeability and enhanced hydrophilicity. Compared with other compounds with similar structures but containing only one 2-nitroimidazole, it had higher hypoxic selectivity. In the uptake experiment of HeLa cells that expressed CAIX, [131I]-N-(3-(3-iodo-4-(2-(2-methoxyethoxy)ethoxy)phenyl)-1-((2-(2-nitro-1H-imidazole-1-yl)ethyl)amino)-1-oxopropan-2-yl)-4-sulfamoylbenzamide (131I-Tyr-06), which contained both 2-nitroimidazole and benzenesulfonamide group, achieved enhanced hypoxic uptake and selectivity through the combination of two targeting groups. The S180 cell blocking experiments of 131I-Tyr-05 and 131I-Tyr-06 showed that the benzenesulfonamide group of the compounds didn't inhibit cellular uptake, and inhibition of cytochrome P450 (CYP450) enzyme had no effect on cellular uptake. In silico ADMET evaluation showed that I-Tyr-05 and I-Tyr-06 possessed acceptable physicochemical and ADMET properties. In conclusion, this work demonstrated the advantages of hypoxia-targeted drugs containing dual bioactive groups compared to a single group, and also found it was a feasible approach to design new dual-targeted drugs by combining 2-nitroimidazole and benzenesulfonamide groups.

Comparison of carbonic anhydrase-IX-targeted trifunctional radioligands between linear- and branched-chain arrangements

Background

Carbonic anhydrase-IX (CA-IX) is overexpressed in tumors due to hypoxic conditions and considered an attractive biomarker for tumor-targeting radioligands. The introduction of an albumin binder (ALB) to radioligands can delay their renal clearance, resulting in increased radioactivity delivered to tumors and decreased renal uptake of radioligands. In this study, we designed novel CA-IX-targeted trifunctional radioligands consisting of imidazothiadiazole sulfonamide (IS) as a CA-IX-targeted ligand, DOTA as a chelator with four free carboxylic groups, and lysine-conjugated 4-(p-iodophenyl)butyric acid (Lys-IPBA) as ALB, with IS-[111In]In-DOTADG-ALB in a linear-chain arrangement and [111In]In-DOTAGA-ALB-IS in a branched-chain arrangement. Fundamental properties of IS-[111In]In-DOTADG-ALB and [111In]In-DOTAGA-ALB-IS were evaluated by in vitro and in vivo assays.

Methods

IS-DOTADG-ALB and DOTAGA-ALB-IS were synthesized and radiolabeled with [111In]InCl3. The stability of IS-[111In]In-DOTADG-ALB and [111In]In-DOTAGA-ALB-IS was evaluated by HPLC analysis after incubation in murine plasma. A cell saturation binding assay using CA-IX-positive HT-29 cells and albumin-binding assay were performed for IS-[111In]In-DOTADG-ALB and [111In]In-DOTAGA-ALB-IS to evaluate their capacity to bind CA-IX and albumin. Biodistribution assays of IS-[111In]In-DOTADG-ALB and [111In]In-DOTAGA-ALB-IS were performed using HT-29 tumor-bearing mice to evaluate their pharmacokinetics.

Results

IS-[111In]In-DOTADG-ALB and [111In]In-DOTAGA-ALB-IS were successfully synthesized by ligand substitution reaction from their corresponding precursors. IS-[111In]In-DOTADG-ALB and [111In]In-DOTAGA-ALB-IS exhibited similar stabilities in murine plasma and affinities to CA-IX, although the affinities to albumin were higher for [111In]In-DOTAGA-ALB-IS compared with IS-[111In]In-DOTADG-ALB. In the biodistribution assays, [111In]In-DOTAGA-ALB-IS showed higher blood retention and tumor accumulation and lower renal uptake than IS-[111In]In-DOTADG-ALB, reflecting their albumin-binding affinities.

Conclusion

These data suggest that the branched-chain arrangement of DOTAGA-ALB-IS may be useful for the design of CA-IX-targeted radioligands consisting of an IS ligand, DOTA, and Lys-IPBA.

Synthesis and Construction of I-124 Labeled Small Molecular Probe for Noninvasive PET Imaging of CAIX Expression

PURPOSE

Carbonic anhydrase IX (CAIX) which is high expression in the most of hypoxic tumor than normal tissue, promoting the growth, invasion, and metastasis of the tumor. Therefore, the study aimed to evaluate the retention and diagnostic ability of [124I]I-XYIMSR- 01 in CAIX-overexpression tumor by using positron emission tomography (PET) imaging.

PROCEDURES

[124/125I]I-XYIMSR- 01 was labeled by 124/125I, and its CAIX-targeting properties in different cell lines were assayed by cell uptaken study. Its diagnose and retention ability in vivo were verified in different CAIX-expression models using PET imaging and biodistribution study. Pathological tissues were obtained for immunohistochemical (IHC) and Hematoxylin-Eosin (HE) staining to explore the relationship between CAIX and hypoxic, and further analyze PET/CT results.

RESULTS

[124I]I-XYIMSR- 01 was obtained with high specific activity, good radiochemical purity, and good stability. The uptake of of [124I]I-XYIMSR- 01 in HT- 29 cells, which have high CAIX expression, was significant higher than that in HCT116 cells with low CAIX expression (12.78 ± 0.47 vs 1.06 ± 0.10, p = 0.000, at 1 h). This indicated that the probe has good targeting capability and specificity for CAIX. In Micro-PET imaging, clear molecular images lasting for 48 h were achieved in HT29 model. Quantitative biodistribution results showed that the tumor and digestive tract background tissues had a good signal-to-noise ratio within 24 h after injection, indicating [124I]I-XYIMSR- 01 could enable delayed imaging in digestive tract tumors (tumor-to-small intestine: 8.79 ± 0.98). Tumors uptakes were also confirmed by IHC pathology.

CONCLUSION

The study have shown that [124I]I-XYIMSR- 01 is an ideal molecular probe for tumor hypoxia, enabling long-term dynamic monitoring and imaging of hypoxic tumors.

[177Lu]Lu-XYIMSR-01: A Novel CAIX-Targeted Radiotherapeutic for Enhanced Treatment of Malignant Glioma

Malignant glioma highly expresses carbonic anhydrase IX (CAIX). This study aimed to develop [177Lu]Lu-XYIMSR-01, a small-molecule therapeutic agent CAIX, to assess its potential for treating malignant glioma. [177Lu]Lu-XYIMSR-01 was synthesized by radiolabeling DOTA-XYIMSR-01 with 177Lu. In vitro assays were conducted to evaluate the affinity for U87MG tumor cells. The probe was injected via the tail vein into subcutaneous and orthotopic U87MG models for micro-SPECT/CT imaging. The survival rates of tumor-bearing mice were assessed after [177Lu]Lu-XYIMSR-01 injection by intratumoral in orthotopic models, including untreated controls and those treated with Temozolomide or combination therapy. After purification, the radiochemical yield of [177Lu]Lu-XYIMSR-01 was 86.47 ± 2.42%, with a radiochemical purity (RCP) of 99%. Its cell uptake in U87MG cells was 3.70 ± 0.57 ‰ AD/105 cells, significantly higher than that in HCT116 cells (0.68 ± 0.16 ‰ AD/105 cells, P = 0.001). In the biodistribution study, [177Lu]Lu-XYIMSR-01 uptake in U87MG tumors was 6.19 ± 1.37%ID/g, with a tumor/muscle ratio of 20.14 ± 3.24. In the orthotopic glioma model, local injection combined with Temozolomide significantly improved survival and inhibited tumor growth. The results indicate that [177Lu]Lu-XYIMSR-01 is a promising therapeutic molecular probe for targeting CAIX, and its combination with Temozolomide significantly enhances treatment outcomes for malignant glioma.

Molecular imaging of renal cell carcinomas: ready for prime time

The clinical diagnosis of renal cell carcinoma (RCC) is constantly evolving. Diagnostic imaging of RCC relying on enhanced computed tomography (CT) and magnetic resonance imaging (MRI) is commonly used for renal mass characterization and assessment of tumour thrombosis, whereas pathology is the gold standard for establishing diagnosis. However, molecular imaging is rapidly improving the clinical management of RCC, particularly clear-cell RCC. Molecular imaging aids in the non-invasive visualization and characterization of specific biomarkers such as carbonic anhydrase IX and CD70 within the tumours, which help to assess tumour heterogeneity and status. Target-specific molecular imaging of RCCs will substantially improve the diagnostic landscape of RCC and will further facilitate clinical decision-making regarding initial staging and re-staging, monitoring of recurrence and metastasis, patient stratification and selection, and the prediction and evaluation of treatment responses.

A CAIX Dual-Targeting Small-Molecule Probe for Noninvasive Imaging of ccRCC

Carbonic anhydrase IX (CAIX), a zinc metal transmembrane protein, is highly expressed in 95% of clear cell renal cell carcinomas (ccRCCs). A positron emission tomography (PET) probe designed to target CAIX in nuclear medicine imaging technology can achieve precise positioning, is noninvasive, and can be used to monitor CAIX expression in lesions in real time. In this study, we constructed a novel acetazolamide dual-targeted small-molecule probe [68Ga]Ga-LF-4, which targets CAIX by binding to a specific amino acid sequence. After attenuation correction, the radiolabeling yield reached 66.95 ± 0.57% (n = 5) after 15 min of reaction and the radiochemical purity reached 99% (n = 5). [68Ga]Ga-LF-4 has good in vitro and in vivo stability, and in vivo safety and high affinity for CAIX, with a Kd value of 6.62 nM. Moreover, [68Ga]Ga-LF-4 could be quickly cleared from the blood in vivo. The biodistribution study revealed that the [68Ga]Ga-LF-4 signal was concentrated in the heart, lung, and kidney after administration, which was the same as that observed in the micro-PET/CT study. In a ccRCC patient-derived xenograft (PDX) model, the signal significantly accumulated in the tumor after administration, where it was retained for up to 4 h. After competitive blockade with LF-4, uptake at the tumor site was significantly reduced. The SUVmax of the probe [68Ga]Ga-LF-4 at the ccRCC tumor site was three times greater than that in the PC3 group with low CAIX expression at 30 min (ccRCC vs PC3:1.86 ± 0.03 vs 0.62 ± 0.01, t = 48.2, P < 0.0001). These results indicate that [68Ga]Ga-LF-4 is a novel small-molecule probe that targets CAIX and can be used to image localized and metastatic ccRCC lesions.

Preclinical and pilot clinical evaluation of a small-molecule carbonic anhydrase IX targeting PET tracer in clear cell renal cell carcinoma

PURPOSE

Clear cell renal cell carcinoma (ccRCC) highly expresses carbonic anhydrase IX (CAIX). The purpose of this study was to evaluate 68Ga-NY104, a small-molecule CAIX-targeting PET agent, in tumor models of ccRCC and patients diagnosed with confirmed, or suspicious, ccRCC.

METHODS

The in vivo and ex vivo biodistribution of 68Ga-NY104 was investigated in CAIX-positive OS-RC-2 xenograft-bearing models. The binding of the tracer was further validated using autoradiography for human ccRCC samples. In addition, three patients with confirmed or suspicious ccRCC were studied.

RESULTS

NY104 can be labeled with high radiochemical yield and purity. It quickly cleared through kidney with α-half-life of 0.15 h. Discernible uptake is noted in the heart, lung, liver, stomach, and kidney. The OS-RC-2 xenograft demonstrated intense uptake 5 min after injection and gradually increased until 3 h after injection with ID%/g of 29.29 ± 6.82. Significant binding was detected using autoradiography on sections of human ccRCC tumor. In the three patients studied, 68Ga-NY104 was well-tolerated and no adverse events were reported. Substantial accumulation was observed in both primary and metastatic lesions in patient 1 and 2 with SUVmax of 42.3. Uptake in the stomach, pancreas, intestine, and choroid plexus was noted. The lesion in third patient was correctly diagnosed as non-metastatic for negative 68Ga-NY104 uptake.

CONCLUSION

68Ga-NY104 can efficiently and specifically bind to CAIX. Given the pilot nature of our study, future clinical studies are warranted to evaluate 68Ga-NY104 for detection of CAIX-positive lesions in patients with ccRCC.

TRIAL REGISTRATION

The clinical evaluation part of this study was retrospectively registered at ClinicalTrial.gov (NCT05728515) as NYPILOT on 6 Feb, 2023.

Carbonic Anhydrase IX Targeting Mn(II)-Based Magnetic Resonance Molecular Imaging Probe for Hypoxia Tumors

Physiological hypoxic conditions in the tumor microenvironment and consequential overexpression of carbonic anhydrase IX (CA IX) are two characteristics shared by numerous types of solid malignant tumors. Early detection with hypoxia assessment is crucial to improve the prognosis and therapy outcomes of hypoxia tumors. Herein, using acetazolamide (AZA) as a CA IX-targeting moiety, we design and synthesize an Mn(II)-based MR imaging probe (named AZA-TA-Mn) incorporating AZA and two Mn(II) chelates of Mn-TyEDTA on a rigid triazine (TA) scaffold. The per Mn relaxivity of AZA-TA-Mn is 2-fold higher than its monomeric Mn-TyEDTA, which allows it for low-dose imaging of hypoxic tumors. In a xenograft mice model of esophageal squamous cell carcinoma (ESCC), a low dosage of AZA-TA-Mn (0.05 mmol/kg) can selectively produce prolonged and stronger contrast enhancement in the tumor compared to the non-specific Gd-DTPA (0.1 mmol/kg). A competition study of co-injection of free AZA and Mn(II) probes confirms the in vivo tumor selectivity of AZA-TA-Mn, resulting in a more than 2.5-fold decreased tumor-to-muscle contrast-to-noise ratio (ΔCNR) at 60 min post-injection. MR imaging results were further supported by the quantitative analysis of Mn tissue levels, as the co-injection of free AZA resulted in significantly reduced Mn accumulation in tumor tissues. Finally, immunofluorescence staining of tissue sections confirms the positive correlation between the tumor accumulation of AZA-TA-Mn and CA IX overexpression. Hence, using CA IX as the hypoxia biomarker, our results illustrate a practical strategy for the development of novel imaging probes for hypoxic tumors.

Identification of cuproptosis-associated subtypes and signature genes for diagnosis and risk prediction of Ulcerative colitis based on machine learning

Background

Ulcerative colitis (UC) is a chronic and debilitating inflammatory bowel disease that impairs quality of life. Cuproptosis, a recently discovered form of cell death, has been linked to many inflammatory diseases, including UC. This study aimed to examine the biological and clinical significance of cuproptosis-related genes in UC.

Methods

Three gene expression profiles of UC were obtained from the Gene Expression Omnibus (GEO) database to form the combined dataset. Differential analysis was performed based on the combined dataset to identify differentially expressed genes, which were intersected with cuproptosis-related genes to obtain differentially expressed cuproptosis-related genes (DECRGs). Machine learning was conducted based on DECRGs to identify signature genes. The prediction model of UC was established using signature genes, and the molecular subtypes related to cuproptosis of UC were identified. Functional enrichment analysis and immune infiltration analysis were used to evaluate the biological characteristics and immune infiltration landscape of signature genes and molecular subtypes.

Results

Seven signature genes (ABCB1, AQP1, BACE1, CA3, COX5A, DAPK2, and LDHD) were identified through the machine learning algorithms, and the nomogram built from these genes had excellent predictive performance. The 298 UC samples were divided into two subtypes through consensus cluster analysis. The results of the functional enrichment analysis and immune infiltration analysis revealed significant differences in gene expression patterns, biological functions, and enrichment pathways between the cuproptosis-related molecular subtypes of UC. The immune infiltration analysis also showed that the immune cell infiltration in cluster A was significantly higher than that of cluster B, and six of the characteristic genes (excluding BACE1) had higher expression levels in subtype B than in subtype A.

Conclusions

This study identified several promising signature genes and developed a nomogram with strong predictive capabilities. The identification of distinct subtypes of UC enhances our current understanding of UC's underlying pathogenesis and provides a foundation for personalized diagnosis and treatment in the future.

New Developments in Carbonic Anhydrase IX-Targeted Fluorescence and Nuclear Imaging Agents

Carbonic anhydrase IX (CAIX) is a tumor-specific and hypoxia-induced biomarker for the molecular imaging of solid malignancies. The nuclear- and optical-imaging of CAIX-expressing tumors have received great attention due to their potential for clinical applications. Nuclear imaging is a powerful tool for the non-invasive diagnosis of primary and metastatic CAIX-positive tumors and for the assessment of responses to antineoplastic treatment. Intraoperative optical fluorescence imaging provides improved visualization for surgeons to increase the discrimination of tumor lesions, allowing for safer surgical treatment. Over the past decades, many CAIX-targeted molecular imaging probes, based on monoclonal antibodies, antibody fragments, peptides, and small molecules, have been reported. In this review, we outline the recent development of CAIX-targeted probes for single-photon emission computerized tomography (SPECT), positron emission tomography (PET), and near-infrared fluorescence imaging (NIRF), and we discuss issues yet to be addressed.

Molecular Imaging of Renal Cell Carcinoma in Precision Medicine

Renal cell carcinoma (RCC) is the sixth most common cancer among men and the ninth among women, and its prognosis is closely correlated with metastasis. Targeted therapy and immunotherapy are the main adjuvant treatments for advanced RCC and require early diagnosis, precise assessment, and prediction of the therapeutic responses. Current conventional imaging methods of RCC only provide structural information rather than biological processes. Noninvasive diagnostic tools are therefore needed to image RCC early and accurately at the molecular level. Nuclear medicine imaging combines the high sensitivity of radionuclides with the high resolution of structural imaging to visualize the metabolic processes and specific targets of RCC for more accurate and reliable diagnosis, staging, prognosis prediction, and response assessment. This review summarizes the most recent applications of nuclear medicine receptor imaging and metabolic imaging in RCC and highlights future development perspectives in the field.

China’s radiopharmaceuticals on expressway: 2014–2021

This review provides an essential overview on the progress of rapidly-developing China’s radiopharmaceuticals in recent years (2014–2021). Our discussion reflects on efforts to develop potential, preclinical, and in-clinical radiopharmaceuticals including the following areas: (1) brain imaging agents, (2) cardiovascular imaging agents, (3) infection and inflammation imaging agents, (4) tumor radiopharmaceuticals, and (5) boron delivery agents (a class of radiopharmaceutical prodrug) for neutron capture therapy. Especially, the progress in basic research, including new radiolabeling methodology, is highlighted from a standpoint of radiopharmaceutical chemistry. Meanwhile, we briefly reflect on the recent major events related to radiopharmaceuticals along with the distribution of major R&D forces (universities, institutions, facilities, and companies), clinical study status, and national regulatory supports. We conclude with a brief commentary on remaining limitations and emerging opportunities for China’s radiopharmaceuticals.

The Acidic Brain-Glycolytic Switch in the Microenvironment of Malignant Glioma

Malignant glioma represents a fatal disease with a poor prognosis and development of resistance mechanisms against conventional therapeutic approaches. The distinct tumor zones of this heterogeneous neoplasm develop their own microenvironment, in which subpopulations of cancer cells communicate. Adaptation to hypoxia in the center of the expanding tumor mass leads to the glycolytic and angiogenic switch, accompanied by upregulation of different glycolytic enzymes, transporters, and other metabolites. These processes render the tumor microenvironment more acidic, remodel the extracellular matrix, and create energy gradients for the metabolic communication between different cancer cells in distinct tumor zones. Escape mechanisms from hypoxia-induced cell death and energy deprivation are the result. The functional consequences are more aggressive and malignant behavior with enhanced proliferation and survival, migration and invasiveness, and the induction of angiogenesis. In this review, we go from the biochemical principles of aerobic and anaerobic glycolysis over the glycolytic switch, regulated by the key transcription factor hypoxia-inducible factor (HIF)-1α, to other important metabolic players like the monocarboxylate transporters (MCTs)1 and 4. We discuss the metabolic symbiosis model via lactate shuttling in the acidic tumor microenvironment and highlight the functional consequences of the glycolytic switch on glioma malignancy. Furthermore, we illustrate regulation by micro ribonucleic acids (miRNAs) and the connection between isocitrate dehydrogenase (IDH) mutation status and glycolytic metabolism. Finally, we give an outlook about the diagnostic and therapeutic implications of the glycolytic switch and the relation to tumor immunity in malignant glioma.

Adding high-dose celecoxib to increase effectiveness of standard glioblastoma chemoirradiation

Over one hundred clinical trials since 2005 have failed to significantly improve the prognosis of glioblastoma. Since 2005, the standard of care has been maximal resection followed by 60Gy irradiation over six weeks with daily temozolomide. With this, a median survival of 2 years can be expected. This short paper reviewed how the pharmacodynamic attributes of an EMA/FDA approved, cheap, generic drug to treat pain, celecoxib, intersect with pathophysiological elements driving glioblastoma growth, such that growth drive inhibition can be expected from celecoxib. The two main attributes of celecoxib are carbonic anhydrase inhibition and cyclooxygenase-2 inhibition. Both attributes individually have been in active study as adjuncts during current cancer treatment, including that of glioblastoma. That research is briefly reviewed here. This paper concludes from the collected data, that starting celecoxib, 600 to 800mg twice daily before surgery and continuing it through the chemoirradiation phase of treatment would be a low-risk intervention with sound rationale.

Radiotracers for positron emission tomography (PET) targeting tumour-associated carbonic anhydrase isoforms

The tumour-associated, cell membrane-bound isoforms IX and XII of human carbonic anhydrase (CA, EC 4.2.1.1) are overexpressed in cancer cells contributing to the hypoxic tumour pH/metabolism regulating machinery and as thus, can serve as markers of malignant neoplastic tissue. Inhibitors of CAs can be employed both for the treatment of hypoxic tumours and in the design of radiotracers for positron emission tomography and imaging of such cancers. The present review provides a comprehensive summary of the progress achieved to-date in the field of developing PET-tracers based on monoclonal antibodies, biomolecules, and small-molecule ligands of CA IX and XII.

In Search of Advanced Tumor Diagnostics and Treatment: Achievements and Perspectives of Carbonic Anhydrase IX Targeted Delivery

The research of how cells sense and adapt the oxygen deficiency has been recognized as worth winning a Nobel Prize in 2019. Understanding hypoxia-driven molecular machinery paved a path for novel strategies in fighting hypoxia-related diseases including cancer. The oxygen depletion inside the tumor provokes HIF-1 dependent gene and protein expression which helps the tumor to survive. For this reason, tumor related molecules are in the spotlight for scientists developing anticancer agents. One such target is carbonic anhydrase IX (CA IX)-a protein located on the outer cell membrane of most hypoxic tumor cells. This offers the opportunity to exploit it as a target for delivery of cytotoxic drugs, dyes, or radioisotopes to cancer cells. Therefore, researchers investigate CA IX specific small molecules and antibodies as tumor-targeting moieties in nanosystems and conjugates which are expected to overcome the limitations of some existing diagnostic and treatment strategies. This review covers the vast majority of CA IX-targeted systems (nanoparticle and conjugate based) for both therapeutic and imaging purposes published up to now. Furthermore, it shows their stage of development and gives an assessment of their clinical translation possibilities.

Micro-PET Imaging Demonstrates 3-O-β-D-Glucopyranosyl Platycodigenin as an Effective Metabolite Affects Permeability of Cell Membrane and Improves Dosimetry of [18F]-Phillygenin in Lung Tissue

Platycodon grandiflorum, as a traditional medicinal plant, is commonly used in the treatment of pulmonary disease. Platycodon saponins are proposed as active ingredients. However, the role of secondary saponin metabolites (SSM) in the traditional use of Platycodon has not yet been fully clarified. In this study, [¹⁸F]-phillygenin ([¹⁸F]-PH) probe was synthesized and thereby used as a tracer for micro-positron emission tomography scanning to explore the effects of platycodon saponins. The membrane permeability with different SSM was evaluated in vitro based on the dye-carrying capacity of fluorescein isothiocyanate. The results showed that total platycodon saponins improved the dosimetry of [¹⁸F]-PH in the lung tissue, and an SSM named 3-O-β-D-glucopyranosyl platycodigenin (GPD⁶⁸²) appreciably changed the distribution of drugs both in vitro and in vivo. We propose that GPD⁶⁸² could be utilized as an important ingredient to help drug delivery to the lung tissue and improve the treatment of respiratory disease.