The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality?
Abstract Background The hypothetical concept of ‘macrocyclic cavity’ is largely employed as useful model to interpret the affinity of metal ions for the macrocyclic chelating ligand 2,2′,2′′,2′′′-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (H4DOTA). It Is hypothesized that a cl...
| Main Author: | |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2023-08-01
|
| Series: | EJNMMI Radiopharmacy and Chemistry |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s41181-023-00202-6 |
| _version_ | 1797450997811904512 |
|---|---|
| author | Adriano Duatti |
| author_facet | Adriano Duatti |
| author_sort | Adriano Duatti |
| collection | DOAJ |
| description | Abstract Background The hypothetical concept of ‘macrocyclic cavity’ is largely employed as useful model to interpret the affinity of metal ions for the macrocyclic chelating ligand 2,2′,2′′,2′′′-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (H4DOTA). It Is hypothesized that a close matching between the size of the macrocyclic cavity and that of the metallic ion is a key parameter to ensure the high-yield formation of stable coordination metal-DOTA complex. This approach has become popular in the design of radiopharmaceuticals containing radiometals and H4DOTA as chelating group. Results Based on X-ray structural data of metallic complexes formed by the ligand H4DOTA upon coordination with a variety of metals, an elementary argument based on Euclidean geometry is presented here that questions the existence of the hypothetical ‘macrocyclic cavity’ within the chelator macrocycle. The geometrical analysis was applied to the complex formed by a Ga3+ ion coordinated to H4DOTA as model compound. Conclusions Application of Euclidean geometry to calculate bond angles in the coordination complex of the ligand H4DOTA with the Ga+3 ion, supposed to incorporate a hypothetical ‘macrocyclic cavity’, revealed that this conceptual entity has no physical reality and, therefore, cannot be considered a meaningful description of a stable structural arrangement for metallic radiopharmaceuticals. |
| first_indexed | 2024-03-09T14:48:34Z |
| format | Article |
| id | doaj.art-a6f2a52e75d9482c89e26dbd83dd9d81 |
| institution | Directory Open Access Journal |
| issn | 2365-421X |
| language | English |
| last_indexed | 2024-03-09T14:48:34Z |
| publishDate | 2023-08-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | EJNMMI Radiopharmacy and Chemistry |
| spelling | doaj.art-a6f2a52e75d9482c89e26dbd83dd9d812023-11-26T14:37:30ZengSpringerOpenEJNMMI Radiopharmacy and Chemistry2365-421X2023-08-01811810.1186/s41181-023-00202-6The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality?Adriano Duatti0Department of Chemical and Pharmaceutical Sciences, University of FerraraAbstract Background The hypothetical concept of ‘macrocyclic cavity’ is largely employed as useful model to interpret the affinity of metal ions for the macrocyclic chelating ligand 2,2′,2′′,2′′′-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (H4DOTA). It Is hypothesized that a close matching between the size of the macrocyclic cavity and that of the metallic ion is a key parameter to ensure the high-yield formation of stable coordination metal-DOTA complex. This approach has become popular in the design of radiopharmaceuticals containing radiometals and H4DOTA as chelating group. Results Based on X-ray structural data of metallic complexes formed by the ligand H4DOTA upon coordination with a variety of metals, an elementary argument based on Euclidean geometry is presented here that questions the existence of the hypothetical ‘macrocyclic cavity’ within the chelator macrocycle. The geometrical analysis was applied to the complex formed by a Ga3+ ion coordinated to H4DOTA as model compound. Conclusions Application of Euclidean geometry to calculate bond angles in the coordination complex of the ligand H4DOTA with the Ga+3 ion, supposed to incorporate a hypothetical ‘macrocyclic cavity’, revealed that this conceptual entity has no physical reality and, therefore, cannot be considered a meaningful description of a stable structural arrangement for metallic radiopharmaceuticals.https://doi.org/10.1186/s41181-023-00202-6DOTAMacrocyclic cavityMacrocyclic ligandsMacrocyclic effectMetallic radiopharmaceuticals |
| spellingShingle | Adriano Duatti The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality? EJNMMI Radiopharmacy and Chemistry DOTA Macrocyclic cavity Macrocyclic ligands Macrocyclic effect Metallic radiopharmaceuticals |
| title | The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality? |
| title_full | The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality? |
| title_fullStr | The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality? |
| title_full_unstemmed | The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality? |
| title_short | The DOTA macrocyclic cavity in metallic radiopharmaceuticals: Mythology or reality? |
| title_sort | dota macrocyclic cavity in metallic radiopharmaceuticals mythology or reality |
| topic | DOTA Macrocyclic cavity Macrocyclic ligands Macrocyclic effect Metallic radiopharmaceuticals |
| url | https://doi.org/10.1186/s41181-023-00202-6 |
| work_keys_str_mv | AT adrianoduatti thedotamacrocycliccavityinmetallicradiopharmaceuticalsmythologyorreality AT adrianoduatti dotamacrocycliccavityinmetallicradiopharmaceuticalsmythologyorreality |