Sreedhara Chaganty

The present study involves the formulation and evaluation of o/w nanoemulsions with two simple edible oils in micro-liter quantities, avoiding large quantities of surfactants and co-surfactants. The nanoemulsions were prepared by high energy emulsification technique. The process optimization was based on the particle size, size distribution and entrapment efficiency in relation with the quantity of oil and concentration of surfactant. The percent drug content was determined by HPLC with UV detector. The particle size, polydispersity index (PDI), and zeta potential of nanoemulsions were determined by using particle sizer. Stability studies at 4°C for two months, centrifugation and freeze-thaw cycling were carried out.  Pharmacokinetic studies of nanoemulsion and marketed dosage form were performed in male SD rats and blood plasma samples were analyzed by LC-MS/MS. The particle size, polydispersity index (PDI), and zeta potential of nanoemulsions were found to be in the range of 26.8±0.72 to 154.6±11.4 nm, 0.09±0.01 to 0.28±0.06 and 0.07±0.01 to -28±0.65 mv respectively. Transmission electron microscopy (TEM) and stability studies revealed the physical stability of the nanoemulsions. The percent drug content was found to be in the range of 73.74±3.79 to 101.16±1.35. The oral bio-availability was significantly increased in nanoemulsion compared with the marketed dosage form. These results showed a successful incorporation of felodipine into nanoemulsion with high drug loading efficiency and good stability. Key words: Sesame oil, olive oil, felodipine, sonication, Oral bioavailability.

  A novel, simple, selective and rugged quantitative method for the determination of Fenofibric acid the active metabolite of fenofibrate  in human plasma (Na2EDTA) using liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated with 200µL human plasma. Fenofibric acid-d6 was used as an internal standard. Analyte and the internal standards were extracted from human plasma by liquid-liquid extraction using Methyl tertiary butyl ether as extraction solvent and ammonium acetate (5mM, pH 2.5) as extraction buffer. The reconstituted samples were chromatographed on a C18 column by using isocratic mobile phase. The method was validated over the concentration range of 79.89–20021.87 ng/mL. The Quattro Premier XE mass spectrometer was operated under the multiple reaction-monitoring mode (MRM) using the electro spray ionization technique for quantification of ion transitions at m/z 317.06/231.00 and 323.24/231.04 for the drug and the internal standard respectively. The method was validated for precision and accuracy, stability, matrix effect, dilution integrity, ruggedness, selectivity and extraction efficiency, and method has been proved to be simple, sensitive, selective, rugged and reproducible. A run time of 2.00 min for each sample made it possible to analyze more than 400 plasma samples per day. The proposed method can be applied for the estimation of the Fenofibric acid in real time plasma samples for pharmacokinetic, drug-drug interaction and toxicological studies.   Key words: Fenofibric acid, Validation, Human Plasma, LC-MS/MS, Electrospray ionization.

A simple, sensitive and rugged quantitative method for the determination of Clopidogrel in human plasma (K2EDTA) using liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated. Clopidogrel-d3 was used as an internal standard. Analyte and the internal standards were extracted from human plasma by liquid-liquid extraction technique using Methyl tertiary butyl ether as extraction solvent and 0.5% formic acid as extraction buffer. The reconstituted samples were chromatographed on a C18 column by using acetonitrile / 5mM ammonium acetate (90/10, V/V) as the mobile phase. The method was validated over the concentration range of 101.98–61028.96 pg/mL. The Quattro Premier XE mass spectrometry was operated under the multiple reaction-monitoring mode (MRM) using the electrospray ionization technique for quantification of ion transitions at m/z 322.13/212.04 and 326.06/215.04 for the drug and the internal standard respectively. The results of the intra and inter batch precision and accuracy studies were well within the acceptable limits. The method has been proved to be simple, sensitive, fast, reliable, rugged and reproducible. A run time of 2.50 min for each sample made it possible to analyze more than 400 plasma samples per day. The proposed method can be applied for the estimation of the drug in real time plasma samples for pharmacokinetic studies. Key words: Clopidogrel, Validation, Human Plasma, LC-MS/MS, Electrospray ionization.