Simulating the hydrodynamic conditions in the United States Pharmacopeia paddle dissolution apparatus

The objective of this work was to examine the feasibility of developing a high-performance computing software system to simulate the United States Pharmacopeia (USP) dissolution apparatus 2 (paddle apparatus) and thus aid in characterizing the fluid hydrodynamics in the method. The USP apparatus was modeled using the hydrodynamic package Fluent. The Gambit program was used to create a “wireframe” of the apparatus and generate the 3-dimensional grids for the computational fluid dynamics solver. The Fluent solver was run on an IBM RS/6000 SP distributed memory parallel processor system, using 8 processors. Configurations with and without a tablet present were developed and examined. Simulations for a liquid-filled vessel at a paddle speed of 50 rpm were generated. Large variations in fluid velocity magnitudes with position in the vessel were evident. Fluid velocity predictions were in good agreement with those previously published, using laser Doppler velocity measurements. A low-velocity domain was evident directly below the center of the rotating paddle. The model was extended to simulate the impact of the presence of a cylindrical tablet in the base of the dissolution vessel. The presence of the tablet complicated the local fluid flow, and large fluid shear rates were evident at the base of the compact. Fluid shear rates varied depending on the tablet surface and the location on the surface and were consistent with the reported asymmetrical dissolution of model tablets. The approach has the potential to explain the variable dissolution results reported and to aid in the design/prediction of optimal dissolution conditions for in vitro-in vivo correlations.     

A new United States Pharmacopeia (USP) Chapter 1046: cell and gene therapy products

The United States Pharmacopeia (USP) has published the first draft of a new information chapter on cell and gene therapy products in January, 2000. The chapter discusses the manufacturing and testing cell and gene therapy products. It is intended for people working in the field as well as for pharmacists and clinicians who would like more information on this subject. This article outlines the background of USP and explains how it became involved with cell and gene therapy and what an information chapter is. It details the subjects covered by the chapter and the philosophy behind the chapter. This draft will be revised based on comments received from the public and then published as a revision subject to further comments before it becomes an official chapter in a supplement to USP 24-NF 19.     

实验兔脚皮炎与相对湿度的相关性及对热原筛选实验的影响分析

目的分析实验兔脚皮炎发病率与相对湿度的相关性及脚皮炎实验兔对热原筛选实验合格率的影响。方法将2006、2007年实验室相对湿度记录、实验兔脚皮炎记录及热原筛选实验记录进行汇总统计,并对数据进行生物学分析。结果实验室相对湿度超过70％时,可导致实验兔脚皮炎发病率的升高,二者存在显著相关性（P〈0．01）;有脚皮炎的实验兔可降低筛选实验的合格率,二者存在显著相关性（P〈0．01）;实验兔基础体温的高低,对筛选合格率有显著影响（P〈0．0001）。结论实验兔的脚皮炎发病率与环境相对湿度有显著的正相关性,当实验室相对湿度超过实验兔适宜湿度范围时,可导致其脚皮炎的发病率上升;有脚皮炎的实验兔与无脚皮炎的实验免相比,可显著降低热原筛选实验的合格率。     

In vitro evaluation of dissolution behavior for a colon-specific drug delivery system (CODES) in multi-pH media using United States Pharmacopeia apparatus II and III

United States Pharmacopeia dissolution apparatus II (paddle) and III (reciprocating cylinder) coupled with automatic sampling devices and software were used to develop a testing procedure for acquiring release profiles of colon-specific drug delivery system (CODES^™) drug formulations in multi-pH media using acetaminophen (APAP) as a model drug. System suitability was examined. Several important instrument parameters and formulation variables were evaluated. Release profiles in artificial gastric fluid (pH 1.2), intestinal fluid (pH 6.8), and pH 5.0 buffer were determined. As expected, the percent release of APAP from coated core tablets was highly pH dependent. A release profile exhibiting a negligible release in pH 1.2 and 6.8 buffers followed by a rapid release in pH 5.0 buffer was established. The drug release in pH 5.0 buffer increased significantly with the increase in the dip or paddle speed but was inversely related to the screen mesh observed at lower dip speeds. It was interesting to note that there was a close similarity (f ₂=80.6) between the release profiles at dip speed 5 dpm and paddle speed 100 rpm. In addition, the release rate was reduced significantly with the increase in acid-soluble Eudragit E coating levels, but lactulose loading showed only a negligible effect. In conclusion, the established reciprocating cylinder method at lower agitation rates can give release profiles equivalent to those for the paddle procedure for CODES^™ drug pH-gradient release testing. Apparatus III was demonstrated to be more convenient and efficient than apparatus II by providing various programmable options in sampling times, agitation rates, and medium changes, which suggested that the apparatus II approach has better potential for in vitro evaluation of colon-specific drug delivery systems.     

不同影响因素对热原实验中兔筛选的影响

目的分析不同影响因素对新西兰兔的初次筛选合格率、二次筛选合格率的影响。方法根据2005版《中国药典》进行测定。结果初次筛选结果中,不同季节、体重值、性别、湿度新西兰兔的筛选率都有显著性差异,筛选时间在7～9月、体重值为1.7～2.0 kg、雄性的新西兰兔、在湿度为61～70%的条件下初次筛选率较高;在二次筛选结果中,不同季节、室温、湿度条件下新西兰兔的筛选率都有显著性差异,筛选时间在1～3月、在室温为22.1～23.0℃、湿度为61～70%的条件下新西兰兔的二次筛选率较高。结论在不同影响因素的条件下,新西兰兔的初次筛选合格率、二次筛选合格率均受到影响。     

Studies on endoparasites of the black bear (Ursus americanus) in the southeastern United States.

Examination of 53 black bears (Ursus americanus) from six states in the southeastern United States revealed at least 17 species of endoparasites, including Sarcocystis sp., Spirometra mansonoides (spargana), Macracanthorhynchus ingens, Ancylostoma caninum, Arthrocephalus lotoris, Baylisascaris transfuga, Capillaria aerophila, Capillaria putorii, Crenosoma sp., Cyathospirura sp., Dirofilaria immitis, Gnathostoma sp., Gongylonema pulchrum, microfilariae, Molineus barbatus, Physaloptera sp. and Strongyloides sp. Twelve of these represent new host records for black bear, and two are considered to be new species. Data are presented on prevalence, intensity and geographic distribution of each species. Pathologic effects were associated with infections of spargana of S. mansonoides and adults of C. aerophilia.     

A Comparison of the British Pharmacopoeia (1973) and United States Pharmacopeia (1975) Methods for Detecting Pseudomonads

The British Pharmacopoeia (Anon. 1973) test for contamination by pseudomonads and the United States Pharmacopeia (Anon. 1975) test for the detection of Pseudomonas aeruginosa have been evaluated using type cultures representative of a wide spectrum of Pseudomonas spp. Media containing cetrimide are recommended by both Pharmacopoeias for the detection of pseudomonads. Of the 28 strains tested only five were detected by the BP method and 11 by the USP method. However, only one strain of P. aeruginosa failed to be detected using the USP method. A correlation between m.i.c. values for cetrimide and detection of the organisms was noted. The BP method failed to detect organisms with m.i.c. values of ± 0.03% whilst the USP method did not detect strains with m.i.c. values ± 0.015%.     

Toxoplasmosis III. Studies Using the Complement-Fixation Test and Fluorescence-Inhibition Test with Sera of Experimentally Exposed Birds

The direct, modified direct and indirect complement-fixation tests and the fluorescence-inhibition test were investigated using sera from pigeons, chickens and turkeys which had been exposed to Toxoplasma gondii. The direct CF test was suitable for use with pigeon sera. The indirect CF method effectively demonstrated antibodies in chicken and turkey sera. FI tests were less sensitive than the CF methods.