A specific, accurate, precise and reproducible high-performance liquid chromatography (HPLC) method was developed for the estimation of rosuvastatin (RST), a novel, synthetic and potent HMG-CoA inhibitor in rat plasma. The assay procedure involved simple liquid-liquid extraction of RST and internal standard (IS, ketoprofen) from a small plasma volume directly into acetonitrile. The organic layer was separated and evaporated under a gentle stream of nitrogen at 40 degrees C. The residue was reconstituted in the mobile phase and injected onto a Kromasil KR 100-5C18 column (4.6 x 250 mm, 5 microm). Mobile phase consisting of 0.05 m formic acid and acetonitrile (55:45, v/v) was used at a flow rate of 1.0 mL/min for the effective separation of RST and IS. The detection of the analyte peak was achieved by monitoring the eluate using a UV detector set at 240 nm. The ratio of peak area of analyte to IS was used for quantification of plasma samples. Nominal retention times of RST and IS were 8.6 and 12.5 min, respectively. The standard curve for RST was linear (r2 > 0.999) in the concentration range 0.02-10 microg/mL. Absolute recoveries of RST and IS were 85-110 and >100%, respectively, from rat plasma. The lower limit of quantification (LLOQ) of RST was 0.02 microg/mL. The inter- and intra-day precisions in the measurement of quality control (QC) samples, 0.02, 0.06, 1.6 and 8.0 microg/mL, were in the range 7.24-12.43% relative standard deviation (RSD) and 2.28-10.23% RSD, respectively. Accuracy in the measurement of QC samples was in the range 93.05-112.17% of the spiked nominal values. Both analyte and IS were stable in the battery of stability studies, viz. benchtop, autosampler and freeze-thaw cycles. RST was found to be stable for a period of 30 days on storage at -80 degrees C. The application of the assay to determine the pharmacokinetic disposition after a single oral dose to rats is described.

The protein and peptide therapeutics have become an important class of drugs due to advancement in molecular biology and recombinant technology. There are more than 100 biopharmaceutical products approved and generating revenue of more than 56 billion US dollars. A safe, effective and patient friendly delivery of these agents is the key to commercial success. Currently, most of therapeutic proteins are administered by the parenteral route which has many drawbacks. Various delivery strategies and specialized companies have evolved over the past few years to improve delivery of proteins and peptides. Polymeric depot and PEGylation technologies have overcome some of the issues associated with parenteral delivery. A considerable research has been focused on non-invasive routes such as pulmonary, per oral and transdermal for delivery of proteins and peptides, in order to increase patient compliance yet their delivery via non-invasive routes remains challenge due to their poor absorption and enzymatic instability. Pulmonary route has shown some success evidenced by recent FDA approval of inhalable insulin. Development of an oral dosage form for protein therapeutics is still the most desirable one but with greater challenge. This review presents the issues of delivery of proteins and peptides, current and potential formulation technologies to improve delivery and current market trends.

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A simple, precise, accurate and rugged reversed-phase high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of five permeability model compounds, viz. antipyrine, metoprolol, ketoprofen, furosemide and phenol red. The method was intended to standardize rat in situ single-pass intestinal perfusion studies to assess the intestinal permeability of drugs in the market as well as new chemical entities. Optimum resolution was achieved by gradient elution on a Symmetry Shield C-18 analytical column with the mobile phase consisting of a mixture of aqueous potassium dihydrogen orthophosphate (pH 5.5; 0.01 m) and methanol at a flow rate of 1.5 mL/min. The retention times of antipyrine, metoprolol, ketoprofen, phenol red and furosemide were about 9, 12, 13, 16 and 17 min, respectively. Data acquisition was carried out using a photo diode array detector in the wavelength range 210-600 nm. Extraction of chromatograms was carried out by timed wavelength. Data obtained in all studies indicated that the method was suitable for the intended purpose. The validated method was found to be linear and precise in the working range. Suitability of storage under various conditions and freeze/thaw impact at cold temperature were established to ensure complete sample recovery without any stability issues. Recovery very close to the spiked amounts indicated that the method was highly accurate and suitable for use on routine basis.

The purpose of the present study was to investigate the influence of a polyhydroxy base, N-acetyl glucamine (also know as Meglumine), as a ternary component on the complexation of DRF-4367, a poorly water-soluble and weakly acidic anti-inflammatory molecule, with 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). The molecular inclusion of DRF-4367 with HPbetaCD alone and in combination with ternary component was aimed at improvement in solubility and, subsequently, dissolution rate-limited oral bioavailability. The solid complexes of DRF-4367 and HPbetaCD with or without meglumine (binary and ternary systems, respectively) were prepared as coevaporated product in different stoichiometric ratios and compared against physical mixture. The formation of inclusion complexes was confirmed by using classical instrumental techniques. Phase solubility studies suggested that meglumine was responsible for solubility improvement via multiple factors rather than just providing a favorable pH. Mechanisms and factors governing solubility enhancement were investigated by using phase solubility and thermodynamic parameters. The complexation of DRF-4367 with HPbetaCD is thermodynamically favored because the Gibbs free energies of transfer of the drug to the cyclodextrin cavity are negative. The solubilization efficiency and stability were further improved while retaining the favorable Gibbs free energies of transfer with the addition of meglumine. Inclusion ternary complex of DRF-4367 with HPbetaCD and meglumine showed significant improvement in dissolution compared with uncomplexed drug and binary system. Moreover, the phenomena of reprecipitation observed with binary system during dissolution could be avoided with meglumine as an enabling ternary component. This improved physicochemical behavior of ternary complex with the novel inclusion of a polyhydroxy base translated into an enhanced oral bioavailability of DRF-4367 compared with either uncomplexed drug or nanosuspension.