Fabrication of multiwalled carbon nanotube-surfactant modified sensor for the direct determination of toxic drug 4-aminoantipyrine☆ / 药物分析学报

A multi-walled carbon nanotube (MWCNT)-cetyltrimethylammonium bromide (CTAB) surfactant composite modified glassy carbon electrode (GCE) was developed as a novel system for the determination of 4-aminoantipyrine(AAP). The oxidation process was irreversible over the pH range studied and exhibited a diffusion controlled behavior. All experimental parameters were optimized. The combination of MWCNT-CTAB endows the biosensor with large surface area, good biological compatibility, electricity and stability, high selectivity and sensitivity. MWCNT-CTAB /GCE electrode gave a linear response for AAP from 5.0 × 10-9 to 4.0 × 10-8 M with a detection limit of 1.63 × 10-10 M. The modified electrode showed good selectivity against interfering species and also exhibited good reproducibility. The present electrochemical sensor based on the MWCNT-CTAB/GCE electrode was applied to the determination of AAP in real samples.

Influence of Sodium CMC and HPMC on the Physical Characteristics of Ofloxacin Floating Matrix Tablets.

Aims: Sustained release floating drug delivery systems or gastro retentive drug delivery systems enables prolonged and continuous input of drug to the upper part of gastrointestinal tract and improves the bioavailability of medication. A new strategy is proposed for the development of floating drug delivery systems of Fluoroquinolone antibiotic, Ofloxacin, a potent moiety for treating UTI’s. Methodology: Various rate retarding polymers like HPMC K4M, HPMC 5 cps and swelling agent as Sodium carboxymethyl cellulose in different proportions were tried and optimized to achieve the drug release for 8 hr. All the formulations were evaluated for floating properties, swelling characteristics and in vitro drug release studies. The in vitro drug release was found to be matrix diffusion controlled. Optimized formulation was subjected to intermediate stability studies at various combinations of temperature and humidity according to ICH guidelines. Results: Lower hardness and higher thickness decreased the floating lag time and increased floating duration. Based on drug release studies, formulation F5 was optimized as the best formulation because it released about 89.27 ±2.6% of the drug at the end of 8 hr while other formulations released not more than 80 ±2.2%. This may be due to high NaCMC content which might have caused excessive channeling, thereby giving a burst release. Optimized formulation F5 was found to follow zero order kinetics with r2 value of 0.993. Conclusion: In conclusion we have been proved that HPMC K4M has retarded the drug release, while HPMC 5cps has facilitated high buoyancy time for the tablets. NaCMC has influenced as channeling agent. Formulation F5 was optimized for its long buoyancy time, prolonged duration of drug release, zero order and diffusion controlled drug release kinetics which can assure 100% bioavailability.