Intravenous injection multiple

Fig. 39.11. (a) One compartment open model for repeated intravenous injection of the same dose D at constant intervals 0. (b) Time course of the plasma concentration Cp with peaks C and troughs C at multiples of the time interval 0. Tlie peaks and troughs tend asymptotically toward the... 

Fig. 14 Plot of plasma concentration versus time showing accumulation following multiple intravenous injections. 

Kobierski LA, Abdi S, DiLorenzo L, Eeroz N, Borsook D. (2003) A single intravenous injection of km5500 (antibiotic spicamycin) produces longterm decreases in multiple sensory hypersensitivities in neuropathic pain. Anesth Analg 97 174-182. 

The vehicle or drug was intracerebroventricularly injected 20 min before tetanus, and saline or 30% ethanol was intravenously injected at a volumn of 2 ml/kg 15 min before tetanus. The AUC from 5 to 60 min after application of tetanus was calculated and defined as an index of magnitude of LTP in each group. The data are represented as the means SEM of the number of observations shown in parentheses. p<0.01 vs. control group. +p<0.05, -HpO.OI vs. ethanol group in Duncan s multiple range test. 

Therefore, these drug molecules must cross the multiple layers of cellular membranes between the site of administration (the blood circulation in the case of intravenous injection) and their intracellular receptors. Small molecules (MW < 400 Da) that are soluble in both water and octanol readily diffuse through the biomembranes. Many hydrophilic small-molecule drugs such as [3-lactam antibiotics12 and classical antifolates13 require specific transporter proteins on the plasma membrane to enter the cytoplasm of the host cells. 

Many injections are formulated as aqueous solutions, with Water for Injections as the vehicle. Their formulation depends upon several factors including the aqueous solubility of the active ingredient, the dose, its thermal stability, the route of administration, and whether the product is to be offered as a multiple-dose product (i.e. with doses removed on different occasions) or as a single-dose form (as the term suggests, only one dose per container). Most injections are prepared as a single-dose form but this is mandatory for certain routes, e.g. spinal injections where the intrathecal route is used, and large volume intravenous infusions. Multiple-dose... 

In the past, studies of the distribution and metabolism of cannabinoids had been hampered by the lack of pure radiolabeled compounds. In 1973, shortly after the radiolabeled cannabinoids became available, Dr. E. G. Lelghty reported the recognition of some unidentified metabolites that were retained In rat liver and spleen up to 15 days after an acute Intravenous or multiple subacute Intraperltoneal Injections of either A -THC or A -THC ). The metabolites could be extracted by methanol and had a greater lipophilicity than the parent THC. These long-retained metabolites were also found In bone marrow ( ) and represented an Increasing percentage of the total cannabinoids found In feces, but not urine (. 

This continuous infusion method can also be employed without urine collection, and plasma clearance is then calculated as CL = infusion rate/Css. Requirements of this method include steady-state plasma concentrations and accmate measmement of infusate concentrations. Plasma clearance can also be determined following a singledose intravenous injection with multiple samples of blood taken to estimate the area under the curve (AUCo oo)- Here clearance is calculated as CL = dose/AUC. These plasma clearance methods commonly yield clearance values 10% to 15% higher than urine collection methods. ... 

The blood radioactivity decreased in a triphasic manner after intravenous injection of [3H]ginsenoside Rgl to mice (Liu and Xiao, 1992). Other Chinese studies have characterized the biotransformation of ginsenoside 20(1S)-Rg2, one of the main constituents of ginseng roots and leaves. Its metabolism is complex and involves multiple hydrolysis reactions in the gastrointestinal tract. Metabolites of 20(5)-Rg2 include 20(5)-Rhl and 20(S)-protopanaxatriol. Details of the biotransformation of 20(5)-Rg2 and chemical structures of the ginsenosides are available in the cited reference (Liu and Xiao, 1992). 

A preparation of Ketamine [2-(Chlorophenyl)-2-(methylamino) cyclohexanone, C23HjgClNO, an anesthetic agent] in an OAV/O multiple emulsion for prolonged drug release was formulated and evaluated. Ketamine is used as a short-acting anesthetic in humans and in some animal species (90). Ketamine is poorly bound to plasma proteins and has a half-life of approximately 4 h following intravenous injection. 

Since parathyroid hormone is not used in routine therapy, but in the diagnosis of hyperparathyroidism, its potential for immunogenicity is limited. Nevertheless, O Rolhrke et al. (1973) reported that intravenous injection of parathyroid hormone elicited an anaphylactic-type reaction in a patient. The patient had never received this hormone and had no history of atopy, but had received multiple blood transfusions in the past. Diagnostic tests (Sect. A.Ill) confirmed the presence of IgE antibodies, which were presumed responsible for the reaction. 

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