[Evaluation of dissolution of osmotic-controlled release paliperidone tablets using the reciprocating cylinder method].

The dissolution profiles of paliperidone from INVEGA(®) 3-mg tablets, osmotic-controlled release tablets, were evaluated by using the reciprocating cylinder method (RC method). We used 4 different compositions of the dissolution fluids, by considering the environment of the tablet in the gastrointestinal tract. After a lag time of 2 to 4 h, paliperidone was approximately dissolved to 24 h by zero-order release. The dissolution characteristics of paliperidone were not affected by the kind of the test medium, pH, and surfactant. In addition, the dissolution of the tablets was evaluated using the paddle method in distilled water, Japanese Pharmacopeia (JP) 1st test fluid, and JP 2nd test fluid. The dissolution profiles of paliperidone obtained using the RC method and the paddle method were very similar. Further, the dispersion of the percentage of the dissolved paliperidone obtained using the RC method and the paddle method was small.

Glycerol-induced folding of unstructured disulfide-deficient lysozyme into a native-like conformation.

2SS[6-127,64-80] variant of lysozyme which has two disulfide bridges, Cys6-Cys127 and Cys64-Cys80, and lacks the other two disulfide bridges, Cys30-Cys115 and Cys76-Cys94, was quite unstructured in water, but a part of the polypeptide chain was gradually frozen into a native-like conformation with increasing glycerol concentration. It was monitored from the protection factors of amide hydrogens against H/D exchange. In solution containing various concentrations of glycerol, H/D exchange reactions were carried out at pH* 3.0 and 4 degrees C. Then, (1)H-(15)N-HSQC spectra of partially deuterated protein were measured in a quenching buffer for H/D exchange (95% DMSO/5% D(2)O mixture at pH* 5.5 adjusted with dichloroacetate). In a solution of 10% glycerol, the protection factors were nearly equal to 10 at most of residues. With increasing glycerol concentration, some selected regions were further protected, and their protection factors reached about a 1000 in 30% glycerol solution. The highly protected residues were included in A-, B-, and C-helices and beta3-strand, and especially centered on Ile 55 and Leu 56. In 2SS[6-127,64-80], long-range interactions were recovered due to the preferential hydration by glycerol in the hydrophobic box of the alpha-domain. Glycerol-induced recovering of the native-like structure is discussed from the viewpoint of molten globules growing with the protein folding. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 665-675, 2009.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com.

Retroperitoneoscopic treatment of ovarian vein syndrome.

In this paper, we describe a case of ovarian vein syndrome (OVS) successfully treated with retroperitoneoscopic techniques. A 41-year-old woman complained with right flank pain, especially with a recumbent position. OVS was diagnosed and ureterolysis and ovarian vein resection were successfully performed, using retroperitoneoscopic techniques. The patient has been completely pain free for 36 months of follow-up. To our knowledge, no previous reports have described the retroperitoneoscopic treatment of OVS. With the minimally invasive approach, postoperative recovery and patient quality of life were markedly improved.