Oral definition

Toxicology. The acute oral and dermal toxicity of naphthalene is low with LD q values for rats from 1780—2500 mg/kg orally (41) and greater than 2000 mg/kg dermally. The inhalation of naphthalene vapors may cause headache, nausea, confusion, and profuse perspiration, and if exposure is severe, vomiting, optic neuritis, and hematuria may occur (28). Chronic exposure studies conducted by the NTP ia mice for two years showed that naphthalene caused irritation to the nasal passages, but no other overt toxicity was noted. Rabbits that received 1—2 g/d of naphthalene either orally or hypodermically developed changes ia the lens of the eye after a few days, foUowed by definite opacity of the lens after several days (41). Rare cases of such corneal epithelium damage ia humans have been reported (28). Naphthalene can be irritating to the skin, and hypersensitivity does occur. 

There are few definitive data to substantiate the efficacy of LTRA therapy in refractory asthma, except for patients with aspirin-sensitive asthma. This is a fairly uncommon form of asthma that occurs generally in adults who often have no prior (i.e., childhood) history of asthma or atopy, may have nasal polyposis, and who often are dependent upon oral corticosteroids for control of their asthma. This syndrome is not specific to aspirin but is provoked by any inhibitors of the cycloxygenase-1 (COX-1) pathway. These patients have been shown to have a genetic defect that causes... 

Practical activities should embody as best as possible the scientifie proeesses that have been preseribed by the American Association for the Advancement of Science observation, elassification, numerieal relations, measurements, time-spaee relations, eommunieation (oral, pictorial, written), deriving of conclusions, prediction ( what would happen if. .hypothesis making, production of operational definitions, identifieation and control of variables, experiment and explanation of experimental data. Different theoretical perspectives should be used with the aim to optimize the positive eognitive and affeetive outcomes. The use, sometimes together, sometimes separately, of different perspeetives can act complimentarily and can lead to positive results (Niaz, 1993 Tsaparhs, 1997). 

The AUC is a measure of bioavailability, i.e. the amount of substance in the central compartment that is available to the organism. It takes a maximal value under intravenous administration, and is usually less after oral administration or parenteral injection (such as under the skin or in muscle). In the latter cases, losses occur in the gut and at the injection sites. The definition also shows that for a constant dose D, the area under the curve varies inversely with the rate of elimination kp and with the volume of distribution V. Figure 39.6 illustrates schematically the different cases that can be obtained by varying the volume of distribution Vp and the rate of elimination k both on linear and semilogarithmic diagrams. These diagrams show that the slope (time course) of the curves are governed by the rate of elimination and that elevation (amplitude) of the curve is determined by the volume of distribution. 

It is critically important to recognize that the treatments of hyperkalemia discussed thus far are transient, temporizing measures. They are intended to provide time to institute definitive therapy aimed at removing excess potassium from the body. Agents that increase potassium excretion from the body include sodium polystyrene sulfonate, loop diuretics, and hemodialysis or hemofiltration (used only in patients with renal failure). Sodium polystyrene sulfonate (Kayexalate , various manufacturers) can be given orally, via NG tube, or as a rectal retention enema and is dosed at 15 to 60 grams in four divided doses per day. 

Studies with rats and chickens given oral doses of TOCP and tn-/ ara-cresyl phosphate provide more definitive evidence that, following absorption, organophosphate esters in hydraulic fluids (or their metabolites) may be widely distributed among tissues with a preferential distribution to fatty tissues, the liver, and the kidneys (Abou-Donia et al. 1990a, 1990b Kurebayashi et al. 1985 Somkuti and Abou-Donia 1990 Suwita and Abou-Donia 1990). 

FMC. 1990a. Non-definitive acute oral toxicity study of Durad 110 in rats. Study No. 190-1143. FMC Corporation, Princeton, NJ. 

Whenever a drug is administered by an extra-vascular route, there is a danger that part of the dose may not reach the blood (i.e., absorption may not be complete). When the intravenous route is used, the drug is placed directly in the blood therefore an IV injection is, by definition, 100% absorbed. The absolute bioavailability of an extravascular dosage form is defined relative to an IV injection. If IV data are not available, the relative bioavailability may be defined relative to a standard dosage form. For example, the bioavailability of a tablet may be defined relative to an oral solution of the drug. 

Pharmacokinetic Definition of Intestinal Absorption (fa), Presystemic Metabolism (Ec and Eh) and Absolute Bioavailability (F) of Drugs Administered Orally to Humans... 

Definition ofi Absorption and Bioavaiiabiiity of Drugs following Oral Administration... 

The general definition of the bioavailability (F) of a drug following oral administration is the rate at, and extent to which, a pharmacologically active drug reaches the systemic circulation. The bioavaiiabiiity (F) of a compound is a consequence of several processes shown in Eq. (1) ... 

Definition of Absorption and Bioavailability of Drugs following Oral Administration 499... 

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