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Testosterone Buciclate
Testosterone buciclate (developmental code names 20 Aet-1, CDB-1781) is a synthetic, injected anabolic–androgenic steroid (AAS) which was never marketed. It was developed in collaboration by the Contraceptive Development Branch (CDB) of the National Institute of Child Health and Human Development (NICHD) and the World Health Organization (WHO) in the 1970s and early 1980s for use in androgen replacement therapy for male hypogonadism and as a potential male contraceptive. It was first described in 1986. The medication is an androgen ester – specifically, the C17β buciclate (4-butylcyclohexane-1-carboxylate) ester of testosterone – and is a prodrug of testosterone with a very long duration of action when used as a depot via intramuscular injection. Testosterone buciclate is formulated as a microcrystalline aqueous suspension with a defined particle size of at least 75% in the range of 10 to 50 μm. A single intramuscular injection of testosterone buciclate has been fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intramuscular Injection
Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have larger and more numerous blood vessels than subcutaneous tissue, leading to faster absorption than subcutaneous or intradermal injections. Medication administered via intramuscular injection is not subject to the first-pass metabolism effect which affects oral medications. Common sites for intramuscular injections include the deltoid muscle of the upper arm and the gluteal muscle of the buttock. In infants, the vastus lateralis muscle of the thigh is commonly used. The injection site must be cleaned before administering the injection, and the injection is then administered in a fast, darting motion to decrease the discomfort to the individual. The volume to be injected in the muscle is usually limited to 2–5 milliliters, depending on in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androgen Ester
An androgen or anabolic steroid ester is an ester of an androgen/anabolic steroid (AAS) such as the natural testosterone or dihydrotestosterone (DHT) or the synthetic nandrolone (19-nortestosterone). Esterification renders AAS into metabolism-resistant prohormones of themselves, improving oral bioavailability, increasing lipophilicity, and extending the elimination half-life (which necessitates less frequent administration). In addition, with intramuscular injection, AAS esters are absorbed more slowly into the body, further improving the elimination half-life. Aside from differences in pharmacokinetics (e.g., duration), these esters essentially have the same effects as the parent drugs. They are used in androgen replacement therapy (ART), among other indications. Examples of androgen esters include testosterone esters such as testosterone cypionate, testosterone enanthate, testosterone propionate, and testosterone undecanoate and nandrolone esters such as nandrolone decanoate and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Residence Time (fluid Dynamics)
The residence time of a fluid parcel is the total time that the parcel has spent inside a control volume (e.g.: a chemical reactor, a lake, a human body). The residence time of a set of parcels is quantified in terms of the frequency distribution of the residence time in the set, which is known as residence time distribution (RTD), or in terms of its average, known as mean residence time. Residence time plays an important role in chemistry and especially in environmental science and pharmacology. Under the name ''lead time'' or ''waiting time'' it plays a central role respectively in supply chain management and queueing theory, where the material that flows is usually discrete instead of continuous. History The concept of residence time originated in models of chemical reactors. The first such model was an ''axial dispersion model'' by Irving Langmuir in 1908. This received little attention for 45 years; other models were developed such as the plug flow reactor model and the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elimination Half-life
Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the blood plasma, and is denoted by the abbreviation t_. This is used to measure the removal of things such as metabolites, drugs, and signalling molecules from the body. Typically, the biological half-life refers to the body's natural cleansing through the function of the liver and through the excretion of the measured substance through the kidneys and intestines. This concept is used when the rate of removal is roughly exponential. In a medical context, half-life explicitly describes the time it takes for the blood plasma concentration of a substance to halve (''plasma half-life'') its steady-state when circulating in the full blood of an organism. This measurement is useful in medicine, pharmacology and pharmacokinetics because it helps det ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physiology
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology. Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells. ''Physiological state'' is the condition of normal function. In contrast, ''pathological state'' refers to abnormal conditions, including human diseases. The Nobel Prize in Physiology or Medicine is awarded by the Royal Swedish Academy of Sciences for exceptional scientific achievements in physiology related to the field of medicine. Foundations Cells Although there are differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Size
Particle size is a notion introduced for comparing dimensions of solid particles ('' flecks''), liquid particles (''droplets''), or gaseous particles ('' bubbles''). The notion of particle size applies to particles in colloids, in ecology, in granular material (whether airborne or not), and to particles that form a granular material (see also grain size). Measurement There are several methods for measuring particle size and particle size distribution. Some of them are based on light, other on ultrasound,Dukhin, A. S. and Goetz, P. J. ''Characterization of liquids, nano- and micro- particulates and porous bodies using Ultrasound'', Elsevier, 2017 or electric field, or gravity, or centrifugation. The use of sieves is a common measurement technique, however this process can be more susceptible to human error and is time consuming. Technology such as dynamic image analysis (DIA) can make particle size distribution analyses much easier. This approach can be seen in instruments lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Suspension
In chemistry, a suspension is a Mixture#Homogeneous and heterogeneous mixtures, heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation. The particles may be macroscopic, visible to the naked eye, usually must be larger than one micrometre, micrometer, and will eventually settling, settle, although the mixture is only classified as a suspension when and while the particles have not settled out. Properties A suspension is a heterogeneous mixture in which the solute particles do not dissolution (chemistry), dissolve, but get suspended throughout the bulk of the solvent, left floating around freely in the medium. The internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation (action), agitation, with the use of certain excipients or suspending agents. An example of a suspension would be sand in water. The suspended particles are visible under a microscope and will settle over time if left undistu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcrystalline
A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but the extreme range of values suggested is 1 to 200 microns. See also * Macrocrystalline * Nanocrystalline silicon * Microcrystalline cellulose * Microcrystalline wax * Protocrystalline * Rock microstructure Rock microstructure includes the texture and small-scale structures of a rock. The words ''texture'' and ''microstructure'' are interchangeable, with the latter preferred in modern geological literature. However, ''texture'' is still acceptable b ... References Mineralogy concepts Petrology concepts {{Petrology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intramuscular Injection
Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have larger and more numerous blood vessels than subcutaneous tissue, leading to faster absorption than subcutaneous or intradermal injections. Medication administered via intramuscular injection is not subject to the first-pass metabolism effect which affects oral medications. Common sites for intramuscular injections include the deltoid muscle of the upper arm and the gluteal muscle of the buttock. In infants, the vastus lateralis muscle of the thigh is commonly used. The injection site must be cleaned before administering the injection, and the injection is then administered in a fast, darting motion to decrease the discomfort to the individual. The volume to be injected in the muscle is usually limited to 2–5 milliliters, depending on in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depot Injection
A depot injection is a term for an injection formulation of a medication which releases slowly over time to permit less frequent administration of a medication. They are designed to increase medication adherence and consistency, especially in patients who commonly forget to take their medicine. Depot injections can be created by modifying the drug molecule itself, as in the case of prodrugs, or by modifying the way it is administered, as in the case of oil/lipid suspensions. Depot injections can have a duration of action of one month or greater and are available for many types of drugs, including antipsychotics and hormones. Purpose Depot injections provide longer duration drug action through slow absorption into the bloodstream. They are usually administered in the muscle, into the skin, or under the skin. The injected medication slowly releases the medication into the bloodstream. It may be used in patients who forget to take their medication; some doctors and patients cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duration Of Action
Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms (for example, infection). Pharmacodynamics and pharmacokinetics are the main branches of pharmacology, being itself a topic of biology interested in the study of the interactions between both endogenous and exogenous chemical substances with living organisms. In particular, pharmacodynamics is the study of how a drug affects an organism, whereas pharmacokinetics is the study of how the organism affects the drug. Both together influence dosing, benefit, and adverse effects. Pharmacodynamics is sometimes abbreviated as PD and pharmacokinetics as PK, especially in combined reference (for example, when speaking of PK/PD models). Pharmacodynamics places particular emphasis on dose–response relationships, that is, the relationships between drug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prodrug
A prodrug is a medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug is absorbed, distributed, metabolized, and excreted (ADME). Prodrugs are often designed to improve bioavailability when a drug itself is poorly absorbed from the gastrointestinal tract. A prodrug may be used to improve how selectively the drug interacts with cells or processes that are not its intended target. This reduces adverse or unintended effects of a drug, especially important in treatments like chemotherapy, which can have severe unintended and undesirable side effects. History Many herbal extracts historically used in medicine contain glycosides (sugar derivatives) of the active agent, which are hydrolyzed in the intestines to release the active and more bioavailable aglycone. For example, salicin is a β-D-glucopyranosid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
