Volume systemic drug administration

The major routes of parenteral administration of drugs are subcutaneous, intramuscular, and intravenous. Other more specialized routes are intrathecal, in-tracistemal, intra-arterial, intraspinal, intraepidural, and intradermal. The intradermal route is not typically used to achieve systemic drug effects. The major routes will be discussed separately. Definitions of the more specialized routes, along with additional information concerning needle sizes, volumes typically administered, formulation constraints, and types of medication administered, are summarized in Table 1. 

Characteristics of the drug and the fluid such as drug volume, osmolality, pH, and density may affect i.v. drug delivery. The frequency and duration of drug administration is also important as is the need for the infusion system to handle multiple drugs. This may lead... 

Absorption from the rectum depends on various physiological factors such as surface area, blood supply, pH, fluid volume, and possible metabolism by microorganisms in the rectum. The rectum is perfused by the inferior and middle rectal arteries, whereas the superior, the middle, and the inferior rectal veins drain the rectum. The latter two are directly connected to the systemic circulation the superior rectal vein drains into the portal system. Drugs absorbed from the lower rectum are carried directly into the systemic circulation, whereas drugs absorbed from the upper rectum are subjected to hepatic first-pass effect. Therefore, a high-clearance drug should be more bioavailable after rectal than oral administration. The volume of fluid in the rectum, the pH of that fluid, and the presence of stool in the rectal vault may affect drug absorption. Because the fluid volume is... 

ACE angiotensin-converting enzyme CNS central nervous system COPD chronic obstructive pulmonary disease DPIs dry-powder inhalers EDTA ethylenediamine tetraacetic acid EDA Eood and Drug Administration EEVi forced expiratory volume in 1 second HIV human immunodeficiency virus IPS idiopathic pneumonia syndrome NSAIDs nonsteroidal anti-inflammatory drugs... 

Fibrous devices as drug delivery system Drug delivery is perhaps one of tlie most explored active feamres of fibrous implantable medical devices. The search for improved drug administration efficiency has led to explore potential dmg delivery systems and dmg reservoirs. As the effectiveness of a dmg is a dose-dependent release profile, adsorption by tissue and disposal, it has been assumed that implantable fibrous medical devices may be used to carry and release the dmg with local effect, an advantageous large volume of embedded dmgs thanks to high surface/volume ratio... 

Mihaly et al. [128] identified the carboxylic acid derivative of primaquine as a major plasma metabolite. After oral administration of 45 mg of primaquine to healthy volunteers, absorption of the drug was rapid, with peak primaquine levels of 153.3 ng/mL at 3 h, followed by an elimination half-life of 7.1 h, systemic clearance of 21.1 L/h, volume of distribution of 205 L and cumulative urinary excretion of 1.3% of the dose. Primaquine was converted rapidly to the carboxylic acid metabolic, which achieved peak levels of 1427 ng/mL at 7 h. 

The terminator of drug action is, of course, elimination. Elimination is a composite of excretion (kidney, etc.) and biotransformation (metabolism). The primary measure of drug elimination from the whole body is clearance, CLt, defined as the volume of plasma fluid removed of drug per unit time. It is a direct measure of the loss of the drug from the system and can be calculated from Eq. (3.5) after IV administration of a dose of the drug. 

Many drugs are administered as parenterals for speed of action because the patient is unable to take oral medication or because the drug is a macromolecule such as a protein that is unable to be orally absorbed intact due to stability and permeability issues. The U.S. Pharmacopoeia defines parenteral articles as preparations intended for injection through the skin or other external boundary tissue, rather than through the alimentary canal. They include intravenous, intramuscular, or subcutaneous injections. Intravenous injections are classified as small volume (<100 mL per container) or large volume (>100 mL per container) injections. The majority of parenteral dosage forms are supplied as ready-to-use solutions or reconstituted into solutions prior to administration. Suspension formulations may also be used,101 although their use is more limited to a subcutaneous (i.e., Novolin Penfill NOVO Nordisk) or intramuscular (i.e., Sandostatin LAR Depot Novartis) injection. Intravenous use of disperse systems is possible but limited (i.e., Doxil Injection Ortho Biotec). 

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