Molecular Imprinting of Benzylpiperazine: A Comparison of the Self-Assembly and Semi-Covalent Approaches
Molecularly imprinted polymers (MIPs) for benzylpiperazine (BZP, <b>1</b>), an illicit designer drug, were developed by using both self-assembly and semi-covalent approaches. From an array of potential functional monomers (FMs) and using a combination of pre-synthetic interaction studies...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-03-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/6/5117 |
| Summary: | Molecularly imprinted polymers (MIPs) for benzylpiperazine (BZP, <b>1</b>), an illicit designer drug, were developed by using both self-assembly and semi-covalent approaches. From an array of potential functional monomers (FMs) and using a combination of pre-synthetic interaction studies (by molecular modelling and NMR analysis) and binding assays, the highest performing self-assembly <b>1</b>-MIPs were confirmed to result from methacrylic acid (<b>7</b>) as FM, ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TRIM) as crosslinkers and chloroform as the porogen and rebinding solvent at template (T): FM ratios of 1:1 and 1:2, giving imprinting factors (IF) 3 to 7. The semi-covalent <b>1</b>-MIPs were designed using benzylpiperazine (4-vinylphenyl) carbamate (<b>16</b>) as the template–monomer adduct in combination with either EDGMA or TRIM. Our comparative analysis showed the semi-covalent polymers to have a stronger affinity for <b>1</b> (significantly lower K<sub>d</sub> values and higher IFs) and faster uptake than the self-assembly systems. Both approaches have comparable cross-reactivity: marginal to low against cocaine (<b>17</b>) and morphine (<b>18</b>) and high against ephedrine (<b>19</b>) and phenylpiperazine (<b>20</b>). They also have comparable selectivity: highly selective towards <b>1</b> against <b>17</b>, moderate against <b>18</b> and non-selective against <b>19</b>. EGDMA-based self-assembly MIPs displayed a greater imprinting effect (higher IFs and NIP-to-MIP K<sub>d</sub> ratios) than TRIM-based MIPs, while the TRIM-based semi-covalent MIP outperformed its EGDMA-based equivalent. By virtue of its modest selectivity against the test illicit drugs, <b>1</b>-MIPs could potentially be used as a dummy MIP for the broad-based capture and enrichment of illicit drug blends for subsequent laboratory analysis. |
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| ISSN: | 1661-6596 1422-0067 |