Conformational polymorphism of a zinc complex with enalapril antihypertensive drug

Determination of Zn2+ in Solid Pharmaceutical Dosage Forms by Means of Spectrophotometry in Micellar Media: Method Validation

In this study, a spectrophotometric method for the quantitative determination of zinc in a dietary supplement was validated. Zinc forms a ternary complex with Xylenol Orange and cetylpyridinium chloride in acetate buffer at pH = 5.5. The complex exhibits an absorption maximum at 560 nm. Linearity (range was 0.5–1.5 µg/mL, and correlation coefficient of the calibration curve was 0.9998), precision (repeatability variation coefficient and reproducibility variation coefficient were 1.57% and 1.77%, respectively), and accuracy (confidence interval of the mean recovery was 98.29–100.55%) of this method fulfil current pharmacopeial requests. Results obtained by spectrophotometric method were statistically compared with ones obtained by atomic absorption spectrometry and good agreement was found. The method can be applied routinely for quality control of solid pharmaceutical dosage forms containing zinc.

Are antibacterial effects of non-antibiotic drugs random or purposeful because of a common evolutionary origin of bacterial and mammalian targets?

Purpose

Advances in structural biology, genetics, bioinformatics, etc. resulted in the availability of an enormous pool of information enabling the analysis of the ancestry of pro- and eukaryotic genes and proteins.

Methods

This review summarizes findings of structural and/or functional homologies of pro- and eukaryotic enzymes catalysing analogous biological reactions because of their highly conserved active centres so that non-antibiotics interacted with bacterial targets.

Results

Protease inhibitors such as staurosporine or camostat inhibited bacterial serine/threonine or serine/tyrosine protein kinases, serine/threonine phosphatases, and serine/threonine kinases, to which penicillin-binding-proteins are linked, so that these drugs synergized with β-lactams, reverted aminoglycoside-resistance and attenuated bacterial virulence. Calcium antagonists such as nitrendipine or verapamil blocked not only prokaryotic ion channels but interacted with negatively charged bacterial cell membranes thus disrupting membrane energetics and inducing membrane stress response resulting in inhibition of P-glycoprotein such as bacterial pumps thus improving anti-mycobacterial activities of rifampicin, tetracycline, fluoroquinolones, bedaquilin and imipenem-activity against Acinetobacter spp. Ciclosporine and tacrolimus attenuated bacterial virulence. ACE-inhibitors like captopril interacted with metallo-β-lactamases thus reverting carbapenem-resistance; prokaryotic carbonic anhydrases were inhibited as well resulting in growth impairment. In general, non-antibiotics exerted weak antibacterial activities on their own but synergized with antibiotics, and/or reverted resistance and/or attenuated virulence.

Conclusions

Data summarized in this review support the theory that prokaryotic proteins represent targets for non-antibiotics because of a common evolutionary origin of bacterial- and mammalian targets resulting in highly conserved active centres of both, pro- and eukaryotic proteins with which the non-antibiotics interact and exert antibacterial actions.