Sipper

It s to be consumed quickly, he said, as though he were describing something experimental. It s not a four-sipper. ... 

A dissolution testing apparams consists of a set of six or eight thermostatted, stirred vessels of an established geometry and volume from the USP guidelines. The dissolution apparatus provides a means to dissolve each sample, but does not provide a means to determine the concentration of the aetive ingredient in the bath. In the most well-established scheme, sipper tubes withdraw samples from each dissolution vessel and send them through a multiport valve to a flow cell sitting in the sample chamber of a UV-vis spectrophotometer. In recent years, moves have been made to make in situ measurements in the dissolution baths by means of fiber-optic probes. There are three possible probe implementations in situ, down shaft, and removable in situ (see Table 4.2). 

In situ probe Slender probe permanently inserted into each dissolution bath in an apparatus Measurement at same location where the sipper tube had been positioned Disturbance of the laminar flow in the stirred vessel. Lean probe desirable... 

FiU the LOCI 100 pi sample loop by sipping the extract through the sample loop using the sipper. station. 

The system is based on an XP Zymate laboratory robot controlled with a 10 slot System V controller using software version XP VI.S2. The system incorporates commerdaUy available hardware, as well as custom hardware. A schematic diagram of the system is shown in Fig. 6.11. The robotic arm and the peripheral laboratory stations that the robotic arm interacts with to perform the appHcation are positioned in a circular configuration. The GC/MS is located adjacent to the bench top, such that the injection valve is close to the sipper station. Peripheral items of hardware with which the robotic arm does not directly interact with are outside the working envelope. 

All assays performed on digester samples were conducted in 100 mM Tris buffer pH 7.5 with substrate incubations at 37 C. Glucose-releasing assays used the same Tris buffer with 0.5% sodium azide added. Colorimetric products from enzyme assays were detected and recorded using a Milton-Roy model 601 spectrophotometer equipped with sipper and data printer. 

Butterstein, G. M., Schadler, M. H., Lysogorski, E., Robin, L., and Sipperly, S. (1985). A naturally occurring compound, 6-methoxybenzoxyzolinone, stimulates reproductive responses in rats. Biology of Reproduction 32,1018-1023. 

The National Institute of Health s (NIH) Guide for the Care and Use of Laboratory Animals [21] recommends that animal cages be sanitized before use, and further, that sohd-bottom rodent cages be washed once or twice a week and cage racks at least monthly. It is recommended that wire-bottom cages and cages for all other animals be washed at least every 2 weeks. Water bottles, sipper tubes, stoppers, other watering equipment, and feeders should be washed once or twice a week. 

Robustness for UV-Vis Analysis. Wavelength accuracy, wavelength repeatability, diluting solvent (i.e., pH, concentration), solution stability, and bubble formation by the sipper can be investigated during validation of the analytical component. 

Once satisfied that the instrument is operating in accordance with its own specification, the end user should ensure that it is fit for purpose for the applications intended. This step is called Operational Qualification, OQ. This process would include writing the Standard Operating Procedure (SOP) and training staff in its use. Further testing may be required to ensure that the instrument performance is in accordance with National and Corporate standards if not carried out in IQ. Frequently, instruments are used with accessories or sub-systems, e.g. sipper systems or other sample presentation devices. Challenge the analytical system with known standards and record what you did. It is necessary to ensure that they work in the way intended and that documented evidence is available to support their use. 

An in situ probe is a slender probe of either transflectance or transmission design that is permanently inserted into each dissolution bath in an apparatus. This has the advantage of allowing measurements at the same physical location in the vessel where the sipper tube had been positioned, according to USP guidelines. A disadvantage is the disturbance of the laminar flow in the stirred vessel - thus there has been an effort to make this probe with as small a diameter as possible (1/8" or less). 

In a third configuration, a probe is dipped into the vessel only when it is time to make a measurement in the vessel. Once the data have been collected, the probe is withdrawn. This minimizes the flow disturbance in the vessel, while still allowing sampling at the same location as the sipper tube. A disadvantage of this method is that a film may form on the optical surfaces of the probe as they dry while the probe is suspended in air over the dissolution bath. 

Reis GJ, Boucher TM, Sipperly ME, et al, Randomised trial of fish oil for prevention of restenosis after coronary angioplasty. Lancet I 989 2(8656) 177-181. 

Safian RD, McCabe CH, Sipperly ME, et al. Initial success and long-term follow-up of percutaneous transluminal coronary... 

Mange, D. and Sipper, M. 1998. Von Neumann s quintessential message genotype + ribotype = phenotype. Artificial Life, 4,225-227. 

Hu JC, O Shea EK, Kim PS, Sauer RT. 1990. Sequence requirements for coiled coils Analysis with X repressor-GCN4 leucine sipper fusions. Science 250 1400-1403. 

In addition, the use of sippers, transfer tubing, and injectors (manual or otherwise) is not practical or reliable enough for these data collection rates. The complex equipment contains numerous moving parts that can malfunction and cause sampling errors. In addition, these systems are prone to dilution-related errors, contamination, sample carryover, leaks, and blockage by air bubbles and particulate matter. 

Fortunately, automated fiber-optic probe-based dissolution systems have begun to appear for these solid dosage-form applications. One such system uses dip-type UV transflectance fiber-optic probes, each coupled to a miniature photodiode array (PDA) spectrophotometer to measure drug release in real time. This fiber-optic dissolution system can analyze immediate- and controlled-release formulations. The system is more accurate and precise than conventional dissolution test systems, and it is easier to set up than conventional manual sampling or automated sipper-sampling systems with analysis by spectrophotometry or HPLC. 

The rate of hydrolysis of substrate was followed in a Beckman Model 25 Spectrophotometer equipped with a sipper cell. The absorbance of the nitrophenolate... 

FIGURE 10.14 Separation of anionic phosphoinositides on a single-sipper microchip. Separation conditions sample injection time, 0.5 s buffer time, 800 s field strength 530 V/cm pressure, —1.65 psi (vacuum) lipid concentration 1.3 xM each and labeled with BODIPY FL on the acyl chain. (Reprinted from Lin, S., et al.. Analytical Biochemistry 314, 101, 2003. With permission.)... 

Quinine-Aversion Test. For the quinine-aversion test, we used the same Y-maze. In this case, however, fluid-deprived mice were trained to avoid the androstenone-containing arm of the Y-maze in training and testing that commenced 5 weeks after exposures for all groups of animals. Quinine-tainted water (1%), paired with androstenone, produced the aversion—each time the animal entered the androstenone-containing arm and licked the sipper tube, it received the quinine. Sweetened water was the reward for correct choices (the non-odorized arm of the Y-maze). 

Aven T, Roed W, Wiencke HS. 2008. Risikoanalyse - prin-sipper og metoder med anvendelser (in Norwegian only). Universitetsforiaget. 

Labs-on-chips that are developed for drug screening need access to microtiter plates, in which the compounds of interest are stored. These chips contain sipper capillaries through which samples are introduced into the microchannels by vacuum. Continuous analysis of samples is possible if the chip contains a sample channel of larger dimensions (approximately in the millimeter scale), through which sample solutions are pumped hydrodynami-cally and which is connected to the separation or reaction channel. The principle is illustrated in Figure 3. To increase the impedance against pressure-induced flows the separation chaimel may be filled with a gel. 

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