OBJECTIVETo prepare the cubic phase gel containing capsaicin and characterize its properties.

METHODThe cubic phases gel composed of glycerol monoolein, capsaicin and water was made by self-emulsion technology. The characterization of cubic phase gel was carried out by cross-polarizing light microscopy (CPLM) and Small Angle X-Ray Scattering (SAXS). The capsaicin content was determined by HPLC analysis.

RESULTUnder CPLM, cubic phase gel showed dark background. SAXS scattering spectra showed the scattering peaks at 0.1096, 0.1334, 0.1557, 0.1883 A(-1) which was compatible with q1:q2:q3:q4 = mean square root of 2: mean square root of 3: mean square root of 4: mean square root of 6. It was well known that the scattering vector ratio was the characteristic of cubic phase and the internal structure was confirmed to be Pn3m (Q224). The linear range for capsaicin determination was 3.25 x 10(-4) - 2.08 x 10(-2) g x L(-1) (R2 = 1). The average recovery was 97.53% with RSD of 2.9% (n=9).

CONCLUSIONCPLM and SAXS technology are suitable to characterize the cubic phase gel The determination of the capsaicin content by HPLC is simple and reproducible.

Capsaicin ; chemistry ; Chemistry, Pharmaceutical ; Microscopy, Polarization ; Plant Extracts ; chemistry ; Scattering, Small Angle

As nanomedicines are developing fast in both academic and market areas, building up suitable methods for nanomedicine analysis with proper techniques is an important subject, requiring further research. The techniques, which could be employed for grain size analysis of nanomedicines, were reviewed. Several key techniques were discussed with their principles, scope of applications, advantages and defects. Their applications to nanomedine analysis were discussed according to the properties of different nanomedicines, with the purpose of providing some suggestions for the control and administration of nanomedicines.
Drug Delivery Systems ; Light ; Microscopy, Electron ; methods ; Microscopy, Scanning Probe ; methods ; Nanoparticles ; analysis ; chemistry ; classification ; Particle Size ; Scattering, Radiation ; Scattering, Small Angle ; Spectrum Analysis, Raman ; methods ; X-Ray Diffraction ; methods

The purpose of this study is to investigate the preparation of hydroxycamptothecine (HCPT)-loaded cubic crystal liquid embolic precursor solution, and evaluate its in vitro embolic efficiency. Phytantriol was used as cubic crystal liquid embolic material, and the optimal formulation was selected according to ternary phase diagram. Polarized light microscopy, differential scanning calorimetry, and small angle X-ray scattering (SAXS) were used to characterize the cubic crystal structure. High performance liquid chromatography and X-ray diffraction analysis were used to investigate the lactone ring of HCPT. In vitro dissolution was preliminary evaluated, and the simulation embolic model was constructed to evaluate the embolic efficiency of precursor solution. Meanwhile, the gelation time and adhesion force were investigated. The results showed that HCPT-loaded precursor solution for embolization had been successfully prepared with low viscosity which was injectable. The precursor solution could transform into Pn3m structure liquid crystal phase gel rapidly when contracting with excess water. The formed HPCT gel remained its lactone form as the same in precursor solution, and expressed the good ability to block the saline flow, and HCPT could keep sustained releasing drug over 30 days. The prepared drug-loaded embolic precursor solution showed a promising potential for vascular embolization and application in clinical treatment of tumor.
Antineoplastic Agents, Phytogenic ; chemistry ; Calorimetry, Differential Scanning ; Camptothecin ; analogs & derivatives ; chemistry ; Delayed-Action Preparations ; chemistry ; Fatty Alcohols ; chemistry ; Liquid Crystals ; Scattering, Small Angle ; Water ; X-Ray Diffraction

Uch37 is a de-ubiquitinating enzyme that is activated by Rpn13 and involved in the proteasomal degradation of proteins. The full-length Uch37 was shown to exhibit low iso-peptidase activity and is thought to be auto-inhibited. Structural comparisons revealed that within a homo-dimer of Uch37, each of the catalytic domains was blocking the other's ubiquitin (Ub)-binding site. This blockage likely prevented Ub from entering the active site of Uch37 and might form the basis of auto-inhibition. To understand the mode of auto-inhibition clearly and shed light on the activation mechanism of Uch37 by Rpn13, we investigated the Uch37-Rpn13 complex using a combination of mutagenesis, biochemical, NMR, and small-angle X-ray scattering (SAXS) techniques. Our results also proved that Uch37 oligomerized in solution and had very low activity against the fluorogenic substrate ubiquitin-7-amino-4-methylcoumarin (Ub-AMC) of de-ubiquitinating enzymes. Uch37Δ(Hb,Hc,KEKE), a truncation removal of the C-terminal extension region (residues 256-329) converted oligomeric Uch37 into a monomeric form that exhibited iso-peptidase activity comparable to that of a truncation-containing the Uch37 catalytic domain only. We also demonstrated that Rpn13C (Rpn13 residues 270-407) could disrupt the oligomerization of Uch37 by sequestering Uch37 and forming a Uch37-Rpn13 complex. Uch37 was activated in such a complex, exhibiting 12-fold-higher activity than Uch37 alone. Time-resolved SAXS (TR-SAXS) and FRET experiments supported the proposed mode of auto-inhibition and the activation mechanism of Uch37 by Rpn13. Rpn13 activated Uch37 by forming a 1:1 stoichiometric complex in which the active site of Uch37 was accessible to Ub.
Binding Sites ; Catalytic Domain ; Chromatography, Gel ; Crystallography, X-Ray ; Humans ; Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Nuclear Magnetic Resonance, Biomolecular ; Protein Binding ; Protein Conformation ; Protein Multimerization ; Scattering, Small Angle ; Ubiquitin Thiolesterase ; chemistry ; genetics ; metabolism ; Ultracentrifugation

Algorithms ; Carrier Proteins ; chemistry ; Crystallography, X-Ray ; Humans ; Magnetic Resonance Spectroscopy ; Molecular Dynamics Simulation ; Nuclear Proteins ; chemistry ; Principal Component Analysis ; Protein Structure, Tertiary ; Proteins ; chemistry ; Scattering, Small Angle ; X-Ray Diffraction ; methods