Dosing techniques

Calver, M.C., J.C. Mclhoy, D.R. King, J.S. Bradley, and J.L. Gardner. 1989b. Assessment of an approximate lethal dose technique for determining the relative susceptibility of non-target species to 1080 toxin. Austral. Wildl. Res. 16 33-40. 

Dosing Techniques. The most frequently used route of administration in dog safety assessment studies is oral. Dosing by capsule is usually the preferred oral route in... 

Dosing Techniques. Oral dosing of ferrets is usually done by gavage. One method is to hold the ferret perpendicular to the floor, insert the appropriate size stainless steel... 

Dosing techniques, such as intramuscular, intradermal, subcutaneous, and intra-peritoneal administration, can be used for the ferret. Care needs to be taken, however, when administering lipophilic compounds by the subcutaneous or intradermal routs, to avoid inadvertently injecting compounds into the ferret s thick layer of subcutaneous fat, which can result in poor absorption (Moody et al., 1985). 

Common Dosing Techniques. Dosing routes and permissible volumes for nonhuman primates vary between laboratories. The volume limitations from one laboratory are presented in Table 16.12. 

Usually, the main purpose of meta-analysis is quantitative. The goal is to develop better overall estimates of the degree of benefit achieved by specific exposure and dosing techniques, based on the combining (pooling) of estimates found in the existing studies of the interventions. This type of meta-analysis is sometimes called a pooled analysis (Gerbarg and Horwitz, 1988) because the analysts pool the observations of many studies and then calculate parameters such as risk ratios or odds ratios from the pooled data. 

The disposition of insulin was shown to be susceptible to non-absorptive losses to metabolism and mucociliary clearance. Modification of the deposition profile of insulin in the lung showed that higher absorption rates were obtained for more peripheral deposition and co-administration of a metabolic inhibitor reduced losses to exopeptidase metabolism [101], It is acknowledged by the investigators that the IPL technique and the dosing technique of Byron and coworkers are not widely accessible and have therefore not been widely adopted [119], Active absorption has also been studied in this system as described in Sect. 6.2.43. 

Franz TJ (1978) The finite dose technique as a valid in vitro model for the study of percutaneous absorption in man. Curr Probl Dermatol 7 58-68. 

Because of the dosing technique associated with the vacuum volumetric method there exists a potential source of error which in principle cannot be avoided on samples that are slow to equilibrate. Figure 14.2 represents a plot of the pressure in the sample cell versus time. The pressure up to time tj represents the equilibrium pressure in the sample cell before a new quantity of adsorbate is admitted. At time adsorbate is admitted into the sample cell and is accompanied by a rapid pressure rise. The pressure then gradually decreases to a new equilibrium value at time t2- If the decay to the new equilibrium pressure is slow, it is possible for open or accessible parts of the surface, such as the interior of wide pores, to contain more adsorbate before equilibrium is attained than after equilibrium is established. Less accessible regions, such as the interior of long narrow pores, will adsorb slowly and as the pressure falls because of adsorption in these pores, desorption must occur from the more accessible pores which tend to equilibrate more rapidly. If a porous sample is subjected to... 

Goodman, M., and B.W. Barry. 1989. Lipid-protein-partitioning theory (LPP) theory of skin enhancer activity Finite dose technique. Int J Pharm 57 29. 

There are two types of dosing techniques commonly used. The first is to start with a large loading dose of 20 g, taken in 5-g increments four times a day, for 2-5 days. This is followed by a lower daily maintenance dose of 2 g or less for up to six weeks. The second... 

Martin et alJ106b have employed low-dose techniques to obtain selected area electron diffraction and high-resolution electron microscopy of these phenylacetylene dendrimer s. 

Leach, C. L., Davidson, P. J., Hasselquist, B. E., and Boudreau, R. J. (2005), Influence of particle size and patient dosing technique on lung deposition of HFA-beclomethasone from a metered dose inhaler,./. Aerosol Med., 18, 379-385. 

The major gaps in the available information on lewisite are the lack of information on the implications of administering lewisite directly to the stomach over a short time and the absence of chronic oral toxicity data from which to derive an RfD. Because of those deficiencies, the RfD for lewisite was estimated by extrapolating from a less-than-ideal animal study to humans. Confidence in the RfD can be increased if subchronic oral toxicity studies in rabbits and rats are conducted to compare the effects of chronic oral exposure to low concentrations of lewisite with the effects of short-term intragastric administration of small volumes of lewisite. Such studies will provide not only the data needed to better understand the implications of dosing techniques but also more pertinent information on whether the rabbit is more appropriate than the rat for deriving an RfD for lewisite. 

Many of the variabilities associated with the lack of standardization of dosing techniques (dosing concentration, volume, applied surface area, application time, etc.) can be somewhat compensated for by... 

While the infinite dose technique has been invaluable in the determination of important skin permeability parameters such as dermal penetration coefficients and in the development of transdermal drug delivery concepts, to mimic in vivo conditions, the so-called finite dose technique was developed. This is essentially a modification of the traditional steady-state method. The important difference is that the skin preparation is supported over the receptor so that the epidermal surface is exposed in a manner that mimics the real-life exposure scenario, and the compound of interest is applied to the surface of the skin in a manner also similar to exposure in vivo. Although the results of such studies may give valuable information about the absorption of materials under specific exposure conditions, they are generally not amenable to extrapolation to other exposures since no invariant skin properties such as penetration coefficients can be readily calculated. 

Toxicity tests may be static, continuous-flow, or static renewal based on the toxicant dosing technique. Static and continuous-flow procedures are more widely used in toxicity tests conducted with pure chemicals and animal test species. Chronic toxicity tests conducted with effluents are usually static renewal, and those with algae are static. There is no change or renewal of the test substance with dilution water in a static test. This design is the simplest and least expensive however, the toxicant concentrations may decrease due to adsorption and biodegradation. The test solutions and dilution water are renewed periodically, usually daily in a static-renewal test. In a continuous-flow test, the dilution water and test substance are continuously or intermittently renewed. The exposure concentrations remain fairly constant and dose-response relationships can be well defined. 

Goodman M and Barry BW. Lipid-protein-Partitioning Theory (LPP) Theory of Skin Enhancer Activity Finite dose Technique. IntJPharm 1989 57 29-40. 

For extended-interval therapy, Cmax.ss values of 20-30 mg/L and Cmin.ss values less than 1 mg/L generally are accepted as appropriate for gram-negative pneumonia patients. A minimum 24-hour dosage interval is chosen for this dosing technique, and the dosing interval is increased in 12- to 24-hour increments for patients with renal dysfunction. 

Taylor CA III, Kosorok MR, Zimmerman SW, Johnson CA. Pharmacokinetics of intraperitoneal epoetin alfa in patients on peritoneal dialysis using an 8-hour dry dwell dosing technique. Am J Kidney Dis 1999 34 657-662. 

The choice of dosing technique runs parallel to the choice of additive. The principal constraints that need to be considered are ... 

Dosing techniques for liquid systems - some advantages and disadvantages... 

Whatever dosing technique is used the following are relevant to reliable chemical treatment ... 

Lower concentrations can be reached if the saturation principle is combined with the dosing technique. In a double-track technique a small carrier gas flux (eg, 1 SCCM) is fed through the saturator and is subsequently mixed with a larger diluting flux, for example 1 SLM, (see Figure 16-6). In this way mole fractions in concentrations between 1 and 1000 ppm can be attained. After this secondary dilution in this type of system, the mole fraction of the proportioning component y is ... 

Goodman, M. and Barry, B.W (1988). Action of penetration enhancers on human skin as assessed by the permeation of model drugs 5-fluorouracil and estradiol. 1. Infinite dose technique, J. Invest Dermatol, 91 323-327. 

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