Pharmacokinetics in drug development: successes and failures - Essay Example

? Pharmacokinetics in drug development: successes and failures Introduction Pharmacokinetics as well as pharmacodynamics are related concepts of in pharmacology. The administration of drugs into the bodies of organisms require effective diagnosis and evaluation to ensure the use of the appropriate drug in treating a disease in the bodies of the organisms. Pharmacodynamics is the study of physiological and biochemical effects of drugs in the bodies of the disease causing microorganisms or parasites residing in other organisms. Drugs are chemical substances administered into the bodies of the organism in order to eliminate a pathogen thereby alleviating the discomfort resulting from such. Being an external chemical substance, the organisms are likely to react differently depending on the mechanism that the drug uses to eliminate the pathogen. Pharmacodynamics analyze these effects by analyzing the processes of treating a disease and the resulting effects. Pharmacokinetics, on the other hand, is a branch of pharmacology that deals with study of the movements of the drugs within the bodies of the organisms. It encompasses the study of distribution and absorption of the administered drugs. The two concepts therefore relate since after the placement of an external substance onto the body of the substance, it has to travel to the specific location in the body within which it kills the pathogen thereby eliminating the discomfort. Pharmacodynamics entails the study of the reaction between the chemical compositions of a drug with the disease causing pathogen. The study therefore analyses the means through which the drug eliminates kills the pathogen and the subsequent method through which it eliminates the residue from the bodies of the organisms. Different drugs have varied reactions once introduced into the bodies of the organisms. This depends with the chemical composition of the drugs. In treating the diseases, most drugs seek to render the pathogens nonfunctional either by killing them or merely inhibiting their activity. This way, the drugs, eliminate the source of the external substance causing discomfort in their hosts thus treating the disease. Effective drugs derive their success through a number of mechanisms including disruption of the cellular membrane of the pathogens. This denatures the microorganisms thereby killing them. Additionally, some drugs react with the enzyme proteins in the microorganisms. This neutralizes the composition of such structures thereby successfully eliminating the foreign substance. Some chemical composition in the drugs also reacts with other parts of the microorganisms such as their carrier proteins and ion channels all of which denature essential structural composition of the microorganisms thereby killing them. However, not all drugs are effective in killing the pathogens thereby curing the medical conditions. Additionally some pathogens such as viruses have no definite deoxyribonucleic acid and therefore evade the drug chemical composition making their elimination more difficult. Some of the most common undesired characteristics of drugs include increasing the probability of cell mutation. Mutation refers to the change in the structure of a cell thereby making it resistant to the chemical composition of a drug. Certain drugs increase the probability of drugs mutating thereby resisting the drug and increasing their effects on their host organism. Additionally, some chemicals in the drugs result in physiological damage of the body tissues thereby injuring the organisms. This results from inappropriate composition of the drug during development. The drug development process requires effective testing to ensure the development of effective drugs that do not harm the organisms in whom they are administered. Pharmacokinetics therefore concern itself with the movement of substances of the external components in the bodies of the organisms. The chemicals in drugs gain access into the bodies of the organisms differently either orally or through injection among other forms after which they should travel efficiently to the appropriate parts of the body. The transportation process takes place inside the plasma, a fluid composition of the blood. This implies that the chemicals must survive the specific environment without reacting with any of the chemical elements of plasma. Pharmacokinetics encompass a number of areas including absorption, distribution, metabolism and excretion, ADME. The four components of pharmacokinetics ensure effectiveness of the drug after administration. However, in some instances, they take effect after liberation a process that releases the drug from the formulation. The inclusion of liberation therefore results in the development of the acronym LADME. Absorption is the primary of the four processes and refers to the process through which the drug enters the blood circulation. Orally administered drugs leave the digestive system soon after swallowing through osmosis and diffusion among any other method depending on the composition of the drug. Injections on the other hand earn the chemical substances direct entry into the blood. After entering the blood, the distribution begins. The process incorporates the actual transportation of the chemicals to the specific tissues and organs in which they are essential. After reaching the specific tissues and organs, the drugs metabolize. Metabolism is the biotransformation of the drug; the drugs break down from parent compounds to daughter metabolites, which therefore react with the pathogens possibly killing such (Kathleen & Bronwen, 2002). Excretion is the final stage in the functionality of drug inside the organism. It is the process through the body eliminates unwarranted substances. Some chemicals accumulate in the body tissues thereby necessitating their elimination. Additionally, after killing the pathogens, the body determines an effective mechanism of eliminating their residues before they replicate thereby possibly re-infecting the body. Excretion therefore includes the transportation of such substances through the blood to the specific organism mandated with the elimination of foreign substances such as the kidneys and the skin. Pharmacokinetics elaborates the nature in which the body affects a specific drug. Before accessing the pathogens, the drug is introduced into the host organism. The placement process and the resultant contact between the two is likely to affect the effectiveness of the drug. Among the most common of such factors, include the dose of administration. A dosage is the amount of the drug administered to a host organism at a time. The dosage considers such pertinent factors as the age of the organism and their energy level. A wrong dosage become ineffective. Besides failing to eliminate the pathogens, such dosages may harm the organism. Dosage must therefore earn a level of accuracy by considering the physiological factors of the organism to ensure the drug effectiveness. Additionally, the site of administration also affects the pharmacokinetics features of the drug. The two affect the absorption of the drug, an integral area that affects the effectiveness of the drug. The placement must consider closeness with the blood vessels thereby ensuring that the distribution process takes place effectually. The effectiveness of a drug relies on its duration of action. This is therefore an integral element of pharmacokinetics, which is a function of numerous parameters including volume of distribution, clearance, elimination half-life and bioavailability. Each of the components function differently but in unison for the realization of a coherent treatment process. Volume of distribution is one of the most essential parameters that refers to the amount of the drug administered to the patient at any moment. It is synonymous to the drug dosage, it requires the consideration of a number of factors in both the host organism and the specific pathogen since it affects the drug absorption rate thereby affecting the entire pharmacokinetics process. The volume of distribution considers the concentration of the drug, which is another important parameter. Concentration refers to the amount of drug in a specific volume of plasma. Elimination half-life on the other hand refers to the amount of time it takes the concentration of the drug to subside in the body of the plasma of the organism thereby reaching half the original quantity. This is important as it helps determine the rate of the drug action in the organism and possibly a measure of its effectiveness. Bioavailability, another important measurable parameter of pharmacokinetics, is the orderly existing fraction of the drug in the plasma of the organism after introduction. Finally, clearance refers to the amount of plasma that the body clears off the effects of the drug per unit time. After reaching the specific tissue, the plasma offsets the drug to enable the reaction to take place. Clearance therefore refers to the rate at which the plasma in the body releases the drug to the organs and tissues. All the parameters of pharmacokinetics affect the drug effectiveness; they are measurable and therefore improvable by ensuring effective chemical composition of the drug. Bibliography Kathleen, K. & Bronwen, B. 2002. Pharmacology for Health Professionals. Amsterdam: Elsevier. Read More