The antimicrobial nalidixic acid as a probe for molecular recognition of α- and β-cyclodextrins
Bibliographic record
Abstract
The inclusion of the antibacterial drug nalidixic acid (NAL) in α- and β-cyclodextrin (CD) cavities was studied using UVvis absorption and voltammetric methods. It was corroborated that the UV absorption bands of NAL are intensified in the presence of α- and β-CDs. A pronounced decrease in the peak currents of NAL was also noticed upon the addition of α- and β-CDs. From the changes in the peak currents, it was concluded that NAL forms 1:1 inclusion complexes with the various hosts, which is also revealed in the phase solubility profile of the NALβ-CD system, as a representative example. From voltammetric data, the logarithm of the binding constants were calculated to be 2.60 and 3.20 for α- and β-CDs, respectively. The magnitude of the formation constants, as well as the Gibbs free energies for NAL with α- and β-CDs, shows that NAL is bound more strongly to β-CD, with a more apolar cavity, than to α-CD. These observations suggest that hydrophobic interaction is the most important recognition element in the binding process. All orientations of entering NAL into the cavity have been considered herein, with the purpose of characterizing the inclusion complex of NAL with CD. Combining the experimental results and molecular modeling and energy calculations on the inclusion complexes yielded a more detailed picture of the solution structure of the complex formed between NAL and either α-CD or β-CD. It was inferred that the inclusion process can occur through the 2-methylpyridine side. An additional hydrogen bond was also found to be formed between the carboxyl group of NAL, which remains outside the β-CD cavity, and the secondary hydroxyl group of β-CD. This hydrogen bond should, therefore, be operating as an important second recognition element in the NALβ-CD system. Key words: cyclodextrins, hostguest association, inclusion complexes, nalidixic acid, solubility, voltammetry.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".