Validated HPLC method for the simultaneous determination of taxol and ellagic acid in a Punica granatum fruit extract containing combination formulation

A simple, rapid, precise and accurate isocratic reversed-phase high performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of paclitaxel and ellagic acid in a combination nanoformulation. Separation was achieved using a 25 x 4.6 mm column, particle size 5 microm C18 reverse phase column (Luna), with a mobile phase consisting of methanol and 0.05% H3PO4, in gradient elution mode with a mobile phase flow rate of 1 mL/min, using UV visible detection at 230 nm. Sharp and well defined peaks were obtained at retention times of 13.75 min. and 11.6 min. for paclitaxel and ellagic acid, respectively. Regression analysis showed a good linear relationship (r2 = 0.996 +/- 0.0011) and (r2 = 0.993 +/- 0.0011) over wide ranges of 5-500 microg/ml and 1-500 microg/ml for paclitaxel and ellagic acid, respectively. LOD and LOQ of paclitaxel were 30 ng/ml and 100 ng/ml, respectively, while for ellagic acid LOD and LOQ were 300 ng/ml and 1 microg/ml, respectively. The accuracy of the method was determined by recovery studies using the standard addition method and was found to be in the range of 99.61-101.21% and 98.70-102.22% for paclitaxel and ellagic acid, respectively. The relative standard deviation (% RSD) for precision, repeatability and robustness was less than 2%. The ellagic acid content in fruits of Punica granatum and combination formulation with paclitaxel was analyzed and found to be 0.04% w/w and 0.0012%w/w, respectively. The proposed, developed and validated HPLC method for the simultaneous quantification of ellagic acid and paclitaxel can be used for the quality control and standardization of several crude drugs and different combination formulations, in which ellagic acid is present.

Formulation of PEG-ylated L-asparaginase loaded poly (lactide-co-glycolide) nanoparticles: influence of Pegylation on enzyme loading, activity and in vitro release

The present paper describes the advantage of PEG-ylation of L-asparaginase before encapsulation over its incorporation in the native form. During encapsulation a considerable amount of native protein undergoes denaturation and forms insoluble aggregates. In an effort to overcome this problem, L-asparaginase was PEG-ylated before subjecting it to the harsh conditions as encountered during double emulsion solvent evaporation technique. L-asparaginase was conjugated with succinimidyl succinate derivative of polyethylene glycol (SS-PEG, MW 5000) followed by characterization of the formed conjugate using size exclusion-HPLC and SDS PAGE. The PEG-ylated L-asparaginase consisted of different isomers from mono to multi PEG-ylated depending upon the number of Lysine residues (14 in case of L-asparaginase) with about 5% as native protein. The specific activity as retained after PEG-ylation was 62.84 +/- 8.2% and further about 82.7% of activity was recovered from the particles. Imitated studies with the native protein confirmed the enhanced stability of the conjugated protein when exposed to the organic solvent and sonication and showed comparatively less encapsulation efficiency due to increased hydrophilicity. Release profiles for native as well as conjugated proteins consisted of sustained release of about 66.66% and 44.45% in 28 days, respectively. The decrease in the release can be attributed to the increase in the molecular weight of the conjugated protein. The study finally proved that PEG-ylation protected the enzyme and prevented it from denaturation during encapsulation.