The qualitative electrochemical determination of clarithromycin and spectroscopic detection of its structural changes at gold electrode

Gastric Acid Powered Nanomotors Release Antibiotics for In Vivo Treatment of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection has ≈75% probability of causing gastric cancer, so it is considered to be the strongest single risk factor for gastric malignancies. However, the harsh gastric acid environment has created obstacles to medical treatment. This work reports a nanomotor with a bottle-shaped container that can be loaded with small molecules of clarithromycin, nano calcium peroxide (CaO₂ ), and Pt nanoparticles (Pt NPs) by ultrasound. Nanomotors can quickly consume gastric acid through the chemical reaction of CaO₂ to temporarily neutralize gastric acid. The product hydrogen peroxide (H₂ O₂ ) is catalytically decomposed into a large amount of oxygen (O₂ ) by Pt NPs. The local concentration gradient of O₂ bubbles causes it to be expelled from the nanobottles through a narrow opening, and then push the nanobottles forward to provide maximum release and prodrug efficacy. Experiments in animal models show that 15 mg nanomotors can safely and quickly neutralize gastric acid in the stomach and simultaneously release prodrugs to achieve good therapeutic effects without causing acute toxicity. H. pylori burden in mice was 2.6 orders of magnitude lower than that in the control group. The stomach returns to normal pH within 1 d after administration.

Brief Overview of Frequently used Macrolides and Analytical Techniques for their Assessment

Background:

Macrolide antibiotics are known as versatile broad-spectrum antibiotics. Macrolides belong to the oldest group of antibacterial agents. The macrolides which are frequently used for clinical purposes are broadly categorized in three classes depending on the number of membered macrocyclic lactone ring. These three classes actually consist of 14, 15 or 16 atoms in macrocyclic lactone ring which are linked through glycosidic bonds. Erythromycin, azithromycin clarithromycin and roxithromycin are frequently used to control against bacterial infections.

Methods:

The quality assurance and quality controls are important tasks in the pharmaceutical industries. Consequently, to check the quality of drugs, there is a strong need to know about alternative analytical methods for the routine analysis. Many methods have been reported in the literature for the quantitative determination of erythromycin, clarithromycin, azithromycin and clarithromycin in pharmaceutical formulations and biological samples.

Results:

This review will cover a brief introduction of erythromycin, azithromycin, clarithromycin and roxithromycin as well as analytical techniques for their assessment. Each developed method has its own merits and demerits.

Conclusion:

Any accurate method could be used for the quality control and quality assurance of macrolide antibiotics according to the availability, performance and procedure of selected instrument as well as skill and expertise of the analyst.

The qualitative determination of oseltamivir phosphate in Tamiflu® capsule by cyclic voltammetry

A gold electrode was applied in the voltammetric determination of oseltamivir phosphate standard in 0.05 M NaHCO3. Oseltamivir phosphate as a standard and as a component of Tamiflu? capsule exhibited the identical cyclic voltammogram. The peaks originated from excipients in capsule do not appear under the applied electrochemical conditions. The electrochemical method for the qualitative determination of oseltamivir phosphate in Tamiflu? capsule by cyclic voltammetry was developed. The presence of oseltamivir phosphate as standard and as a content of Tamiflu? capsule in electrolyte as well as their concentrations were simultaneously checked by HPLC. The lack of the current/concentration dependency was established. The not pretreated glassy carbon electrode cannot be used for the determination of oseltamivir phosphate under identical experimental conditions presented for gold electrode.

A study of the electrochemical behavior of methomyl on a gold electrode in a neutral electrolyte

A gold electrode was used for the qualitative and quantitative electrochemical determination of analytical methomyl in a neutral electrolyte (0.050 M NaHCO3) using cyclic linear sweep voltammetry. In the potential range from -800 mV vs. SCE to 1000 mV vs. SCE the analytical methomyl was quantitatively determined in the concentration range 4.0-16 mg L-1. In the potential range from -1300 mV vs. SCE to 1300 mV vs. SCE, methomyl was qualitatively determined by two anodic and four cathodic reactions. Cycling the potential in this range for 150 min caused the degradation of the molecule, which was confirmed by HPLC analysis. On the other hand, technical methomyl exhibited an inhibition of the gold electrode surface due to the impurities.

A study of the electrochemical activity of some macrolide antibiotics on a gold electrode in a neutral electrolyte

The aim of the present study is to present the different reactivity of azithromycin and clarithromycin (pure and commercial) at a gold electrode in neutral electrolyte using cyclic linear sweep voltammetry under the same experimental conditions. A gold electrode was successfully used for the electrochemical qualitative and quantitative determination of azithromycin dihydrate and azithromycin from capsules (Hemomycin?) and for the separation of azithromycin from one of the excipients, lactose monohydrate. The good catalytically activity of the gold electrode was employed only for the qualitative electrochemical determination of pure clarithromycin by appearance of one cathodic and four anodic reactions, which enabled structural changes in this molecule during electrochemical reactions to be studied. Commercial clarithromycin, Clathrocyn? was qualitative determined by one reproducible anodic reaction. The activity of one of the excipients, Avicel, observed as a cathodic peak at different potential from the cathodic peak obtained with pure clarithromicin was used for the determination of its presence in Clathrocyn? tablets. FTIR Analysis showed the apparent changes in structure of pure clarithromycin, as well as in the molecule of clarithromycin in Clathrocyn? tablets. HPLC Analysis showed a significant decrease in the concentration of azithromycin, Hemomycin? clarithromycin and Clathrocyn? after the electrochemical reactions.