A near-infrared diffuse reflectance analysis method for the noninvasive quantitative analysis of ambroxol hydrochloride tablets / 药学学报

<p><b>AIM</b>To develop a near-infrared diffuse reflectance analysis (NIRDRA) method for rapid noninvasive quantitative determination of ambroxol hydrochloride in half-finished product particles and non-blister-packed, blistered tablets.</p><p><b>METHODS</b>All spectra were measured with a Fourier transform spectrometer equipped with a PbS and a InGaAs detector, an external integrating sphere, a rotating sample cup, and a fibre-optic probe for reflectance measurements. All samples were scanned from 12,000 cm-1 to 4,000 cm-1, and each sample spectrum was obtained as an automatic mean of 64 scans. No spectrum pre-processing method was used, and spectral regions, 4,602-4,247, 12,000-7,498 and 6,102-5,446, 12,000-5,446 cm-1 were selected to develope mathematical models by partial least square method for half-finished product particles and non-blister-packed, blistered tablets samples, respectively.</p><p><b>RESULTS</b>The optimal rank and mean square error determined for half-finished product particles and non-blister-packed, blistered tablets samples by cross validation method all was 6 and 0.306, 0.972 and 1.492, respectively, the average recovery was 100%, 100% and 102% respectively; and the RSD was 1.17%, 1.70% and 1.78% respectively.</p><p><b>CONCLUSION</b>Results showed that the NIRDRA method was rapid, simple, noninvasive and sensitive, and it can be applied to assay the content of ambroxol hydrochloride in half-finished product particles non-blister-packed and blistered tablets.</p>

Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry / 药学学报

<p><b>AIM</b>To determine the molecular weight and first-order structure of somatostatin.</p><p><b>METHODS</b>The molecular weight of somatostatin was determined by electrospray ionization mass spectrometry. Somatostatin was deoxidized by 2-mercaptoethanol. A series of typical fragment ions of deoxidized product were obtained by insource collision-induced dissociation (CID).</p><p><b>RESULTS</b>The m/z of quasi-molecular ion [M + H]+ of somatostatin was 1,637.8 and [M + Na]+ was 1,659.5. The m/z of double-charge ion [M + 2H]2+ was 819.5 and [M + H + Na]2+ was 830.3. It showed that the molecular weight of somatostatin was 1,636.7. The y and b series of fragment ions of deoxidized product were obtained by adjusting the fragmentor voltage. It was determined that the first-order structure of deoxidized product of somatostatin was A-G-C-K-N-F-F-W-K-T-F-T-S-C.</p><p><b>CONCLUSION</b>The molecular weight and first-order structure of somatostatin were confirmed.</p>

Determination of cyclovirobuxine D by RP-HPLC with precolumn fluorescence derivatization / 药学学报

<p><b>AIM</b>To establish a RP-HPLC method for determination of cyclovirobuxine D.</p><p><b>METHODS</b>Cyclovirobuxine D reacted with a derivative reagent 1-naphthyl isocyanate in chloroform to form fluorescence derivatives, stopped the reaction by adding the mobile phase and then directly injected the solution into the chromatograph to seperate it by RP-HPLC. The analysis was carried out on C18 column, the mobile phase is methanol-water (85:15), the excitation wavelength was set at 305 nm, emission at wavelength 385 nm, and the flow rate was 1 mL.min-1. The effect of several factors including the reaction medium, temperature, time and amount of 1-naphthyl isocyanate on the yield of the derivatization was also investigated systematically.</p><p><b>RESULTS</b>A simple and rapid RP-HPLC method for the simultaneous isolation and analysis of cyclovirobuxine D and its related substances was developed, and the absence of interference between the derivative peak responses of cyclovirobuxine D and its related substances were verified by UV diode array detecter and MS. The linearity was obtained from 0.75 microgram.mL-1 to 2.5 micrograms.mL-1 of cyclovirobuxine D derivatives with a correlation coefficient of 0.9991. The detection limit of cyclovirobuxine D derivative was 1 ng.mL-1, the repeatability of derivatization was good with relative standard derivation no more than 1.2% and derivative was stable within 48 h. The method described conforms to the validation of China Pharmacopiea compendial methods used for pharmaceutical products in general.</p><p><b>CONCLUSION</b>The established method is proved to be reliable quantitative method for the quality control of cyclovirobuxine D.</p>