A validated RP-HPLC method for the determination of piperidone analogue of curcumin.

Curcumin (Diferuloylmethane) is a natural product extracted from the root of Curcuma longa. 5-Bis (4-hydroxy-3-methoxybenzylidene)-N-methyl-4-piperidone, the piperidone analogue of curcumin (PAC), was one of the analogues that, demonstrated potential anticancer effects against breast and colon cancers compared with native curcumin. A simple, accurate, and rapid isocratic reverse phase high performance liquid chromatography (HPLC) analytical method utilizing UV detection was developed and validated for the determination of PAC utilizing C18 column with run time was 7 min. Chromatogram showed a peak of PAC at retention time of 5.8±0.92 min. The method was validated for linearity, accuracy, precision, limit of detection, limit of quantitation and robustness. Linear relationship (r > 0.99) was observed between AUP of PAC and the corresponding concentrations over 100-10000µg/mL. The LOQ of this assay was 3.9ng/mL with a corresponding relative standard deviation of 4.8 and 4.0%. The LOD was 13.1ng/mL at a signal-to-noise ratio of >3.

Development of a method for quantitative determination of the cytotoxic agent piplartine (piperlongumine) in multiple skin layers.

This study reports the development of a simple and reproducible method, with high rates of recovery, to extract the cytotoxic agent piplartine from skin layers, and a sensitive and rapid UV-HPLC method for its quantification. Considering the potential of piplartine for topical treatment of skin cancer, this method may find application for formulation development and pharmacokinetics studies to assess cutaneous bioavailability. Porcine skin was employed as a model for human tissue. Piplartine was extracted from the stratum corneum (SC) and remaining viable skin layers (VS) using methanol, vortex homogenization and bath sonication, and subsequently assayed by HPLC using a C18 column, and 1:1 (v/v) acetonitrile-water (adjusted to pH 4.0 with acetic acid 0.1%) as mobile phase. The quantification limit of piplartine was 0.2 µg/mL (0.6 µm), and the assay was linear up to 5 µg/mL (15.8 µm), with within-day and between-days assay coefficients of variation and relative errors <15%. Piplartine recovery from SC and VS varied from 86 to 96%. The method was suitable to assay samples from skin penetration studies, enabling detection of differences in cutaneous delivery in different skin compartments resulting from treatment with various formulations and time periods.

Spectroscopic (far or terahertz, mid-infrared and Raman) investigation, thermal analysis and biological activity of piplartine.

Research in the field of medicinal plants including Piper species like long pepper (Piper longum L.- Piperaceae) is increasing all over the world due to its use in traditional and Ayurvedic medicine. Piplartine (piperlongumine, 5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)-pyridinone), a biologically active alkaloid/amide was isolated from the phytochemical investigations of Piper species, as long pepper. This alkaloid has cytotoxic, anti-fungal, anti-diabetic, anti-platelet aggregation, anti-tumoral, anxiolytic, anti-depressant, anti-leishmanial, and genotoxic activities, but, its anticancer property is the most promising and has been widely explored. The main purpose of the work is to present a solid state characterization of PPTN using thermal analysis and vibrational spectroscopy. Quantum mechanical calculations based on the density functional theory was also applied to investigate the molecular conformation and vibrational spectrum, which was compared with experimental results obtained by Raman scattering, far (terahertz) and mid-infrared adsorption spectroscopy. NBO analysis has been performed which predict that most intensive interactions in PPTN are the hyperconjugative interactions between n(1) N6 and π*(O1C7) having delocalization energy of 50.53kcal/mol, Topological parameters have been analyzed using 'AIM' analysis which governs the three bond critical points (BCPs), one di-hydrogen, and four ring critical points (RCPs). MEP surface has been plotted which forecast that the most negative region is associated with the electronegative oxygen atoms (sites for nucleophilic activity). Theoretically, to confirm that the title compound has anti-cancer, anti-diabetic and anti-platelet aggregation activities, it was analyzed by molecular docking interactions with the corresponding target receptors. The obtained values of H-bonding parameters and binding affinity prove that its anti-cancer activity is the more prominent than the other properties.

A comprehensive gas chromatography procedure for measurement of drugs in biological materials.

Procedures have been developed for the determination in serum and urine of 21 drugs which include all of the barbiturates, methyprylon, glutethimide, meprobamate, propoxyphene, methaqualone, primidone, diphenylhydantoin, methadone, codeine, morphine, amphetamine and methamphetamine. The method involves pipeting 1.0 ml of serum or urine into an extraction tube, adding an internal standard together with either a pH 4.9 or pH 8.3 buffer and extracting with chloroform. The drugs in the extract are concentrated by exaporation of the organic layer and identified and quantitated by gas-liquid chromatography (GLC) using a column packed with 3 percent OV 17. GLC analysis times are kept below seven minutes by using temperature programming which allows good separations of drugs of widely varying volatilities. All calculations are based on peak areas determined by an electronic integrator. Losses of drugs during extraction, evaporation and chromatography steps are compensated for by the use of internal standards. Actual extraction efficiencies of drugs from serum or urine range from 75 to 100 percent although recoveries, based on standards carried through the entire procedures, are quantitative. Precision (s.d.) based on replicate determinations is approximately plus or minus 0.2 mg per dl.