SYNTHESIS OF NEW LEVOFLOXACIN SELECTIVE MEMBRANE SENSOR BASED ON MOLECULARLY IMPRINTED POLYMERS.

Two molecular imprinted polymer (MIP) membranes for Levofloxacin (LEV) were prepared based on PVC matrix. The imprinted polymers were prepared by polymerization of styrene (STY) as monomer, N,N methylene di acrylamide as a cross linker ,benzoyl peroxide (BPO) as an initiator and levofloxacin as a template. Di methyl adepate (DMA) and acetophenone (AOPH) were used as plasticizers , the molecular imprinted membranes and the non molecular imprinted membranes were prepared. The slopes and detection limits of the liquid electrodes ranged from -21.96 – -19.38 mV/decade and 2×10-4M- 4×10-4M, and Its response time was around 1 minute, respectively. The liquid electrodes were packed with 0.1 M standard drug solution and its response were stable at pH ranges from 1.0 to 11.0 and with good selectivity for more than several type. The electrodes produced have been successfully applied in preparation of the pharmaceutical sample for the determination of the analyte without any time consuming pretreatment steps.

Voltammetric quantification of an anesthetic drug propofol (2,6-diisopropylphenol) on boron-doped diamond electrode in the pharmaceutical formulations

In this paper, the detailed electrochemistry of propofol (PRO) which is one of the intravenous agents commonly used for sedative-hypnotic purposes was examined. In cyclic voltammetry, the agent showed one irreversible and diffusion?controlled oxidation peak, resulting in the formation of a couple with a reduction and re-oxidation wave at less positive potentials. The effect of electrode pretreatment procedures on the electrochemical response of PRO was investigated by using square wave voltammetry (SWV) and the optimum procedure was used to improve the signal response in subsequent studies. Quantification of PRO was done based on the first oxidation peak using SWV. After optimization of all variables, the linear working range of PRO was found to be between 2.5 ?g mL-1 (1.4?10-5 mol L-1) and 160.0 ?g mL-1 (1.1?10-3 mol L-1, n=15) with a detection limit 0.71 ?g mL-1 (3.9?10-6 mol L-1). No noteworthy interference effect was detected. Also, the developed method was used for quantification of PRO in pharmaceutical sample.

SYNTHESIS NEW LIQUID ELECTRODES FOR DETERMINATION DOMPERIDONE MALEATE BASED ON A MOLECULARLY IMPRINTED POLYMER

Liquid electrodes of domperidone maleate (DOMP) imprinted polymer were synthesis based on precipitation polymerization mechanism. The molecularly imprinted (MIP) and non-imprinted (NIP) polymers were synthesized using DOMP as a template. By methyl methacrylate (MMA) as monomer, N,Nmethylenebisacrylamide (NMAA) and ethylene glycol dimethacrylate (EGDMA) as cross-linkers and benzoyl peroxide (BP) as an initiator. The molecularly imprinted membranes were synthesis using acetophenone (APH), di-butyl sabacate (DBS), Di octylphthalate (DOPH) and triolyl phosphate (TP)as plasticizers in PVC matrix. The slopes and limit of detection of liquid electrodes obtained from the calibration curves ranged from (-18.88– -29.01) mV/decade and (4.0 × 10-5 – 6.0 × 10-5) M, respectively and the response time was about 60 seconds. The Liquid electrodes were filled with (10-2 M) standard solution of the drug and observed stable response for a pH ranged from 2.0 to 11.0 and with good selectivity for over several species. The fresh electrodes of synthesis were effectively used in the pharmaceutical sample to determine DOMP without any time consuming pretreatment measures.

Spectroelectrochemical Determination of Isoprenaline in a Pharmaceutical Sample

UV/Vis absorption spectroelectrochemistry (SEC) is a multi-response technique that has been commonly used for the characterization of materials and the study of reaction mechanisms. However, it has been scarcely used for quantitative purposes. SEC allows us to obtain two analytical signals simultaneously, yielding a dual sensor in just one experiment. In the last years, our group has developed new devices useful for analysis. In this work, a SEC device in parallel configuration, based on optical fibers fixed on screen-printed electrodes, was used to determine isoprenaline in a commercial drug, using both, the electrochemical and the spectroscopic signals. In this commercial drug, isoprenaline is accompanied in solution by other compounds. Among them is sodium metabisulfite, an antioxidant that strongly interferes in the isoprenaline determination. A simple pretreatment of the drug sample by bubbling wet-air allows us to avoid the interference of metabisulfite. Here, we demonstrate again the capabilities of UV/Vis absorption SEC as double sensor for analysis and we propose a simple pretreatment to remove interfering compounds.

Development and Validation of a Microbiological Agar Assay for Determination of Thiamphenicol in Soft Capsules

Background: Thiamphenicol belongs to the amphenicol class of antibiotic and possesses a broad-spectrum antimicrobial activity. An alternative microbiological assay for quantification of thiamphenicol in pharmaceutical formulations has not yet been reported in the literature. Objective: This study aimed to develop and validate an agar diffusion method for quantification of thiamphenicol in soft capsules. Methods: The assay was based on the inhibitory effect of thiamphenicol on the following: a strain of Kocuria rhizophila ATCC 9341, used as the test microorganism, Antibiotic 1culture medium, phosphate buffer pH 6, 0, inoculum at a concentration of 1%, as well as standard and sample solutions at the concentrations of 20.0, 40.0 and 80.0 μg mL-1. Results: The method validation yielded good results for the parameters of linearity, precision, accuracy, robustness and selectivity. The experimental statistic results were analyzed using analysis of variance (ANOVA). The method was found to be linear (r2 = 0.9992) in the range of 20-80 μg mL-1, precise (inter-assay R.S.D = 0.09%), accurate (R.S.D. = 4.65%), specific, and robust. Conclusion: The results demonstrated the validity of the proposed bioassay, which allows for reliable quantification of thiamphenicol in a pharmaceutical sample. An alternative methodology for thiamphenicol determination in routine quality control has been reported herein.

Synthesis New Liquid Electrodes for Determination Lansoprzole Based on a Molecularly Imprinted Polymer

Liquid electrodes of Lansoprazole (LP) imprinted polymer was synthesis based on precipitation polymerization mechanism. The molecularly imprinted (MIP) and non-imprinted (NIP) polymers were synthesized using LP as a template. By methyl methacrylate (MMA) as a monomer, Pentaerythritol tetraacrylate (PTA) and ethylene glycol dimethacrylate (EGDMA) as cross-linkers and benzoyl peroxide (BP) as an initiator. The molecularly imprinted membranes were synthesized using Dimethyl adipate (DMA), Dibutyl phthalate (DBPH), Dioctyl phthalate(DOPH), and Nitrobenzene (NB) as plasticizers in PVC matrix. The slopes and limit of detection of liquid electrodes obtained from the calibration curves ranged from (-17.85– -20.89) mV/decade and 1.8 x 10-5–6.0 x 10-6 M, respectively, and the response time was about 60 seconds. The Liquid electrodes were filled with 10-2 M standard solution of the drug and observed stable response for a pH ranged from 2.0 to 11.0 and with good selectivity for over several species. The fresh electrodes of synthesis were effectively used in the pharmaceutical sample to determine LP without any time-consuming pretreatment measures.