Disadvantages Of Pharmaparticles As A Drug Delivery System

When formulated as modified release dosage forms, pellets are less susceptible to dose dumping than the reservoir-type single unit formulations.4 Micropellets technology delivers almost perfectly spherical particles exhibiting a very narrow particle size distribution and excellent flow properties and these are characterized by a smooth surface free of dust and thus provide optimal conditions for subsequent film coating. Controlled release pellets are manufactured either to deliver the bioactive agent at a specific site within the GIT or to sustain the action of drugs over an extended period of time. While these results have been traditionally achieved through the application of a functional coating material, at times the core pellets themselves have been modified to provide the desired effect. This further enhances the role of pellets in oral dosage form

*Rectal administration – Medicines administered into the body by this route are absorbed very quickly. Suppositories are available for this route of administration and are inserted high into the rectum.

Absorption – “How the drugs enter the circulation process through the body, and how they resist general breakdown by the stomach, liver, and the intestines”. Some of the factors that affect the absorption of drugs in the body is as follows, “acidity of the stomach, Physiochemical properties, Presence of food in the stomach or intestine, and Routes of administration”,

B. Distribution-" refers to the movement of the drug through the blood stream to a specific site of action."( pg.1095 Pillitteri)

Based on ¨Principles of Pharmacokinetics¨, ¨pharmacokinetics is the study of absorption, distribution, metabolism, and excretion¨ (Ratain 2003). In other words, the drug's pharmacokinetics determines the duration and the intensity of the effect on the body. Absorption rate can be affected by the drug itself, such as: rate of dissolution, lipid solubility, and route (VandeWaa 2016). The absorption process starts by the route of admission, in this case oral. The oral, or by mouth, route of administration for drugs is the most common. When a pill is taken by mouth, it travels down to the stomach, were most pills dissolve. While in the stomach, some kinds of pills are absorbed into the stomach lining, but some move on to the small intestine. Every pill eventually ends up in the bloodstream and circulate through the body to tissues and organs (Howell 2017). Once passive diffusion occurs, the cells absorb the molecules of the medicine. Then, the molecules of the medicine will exit the cells and travel in the bloodstream for the distribution process.

Some portion of a drug may be lost as it is digested. Enzymes in the gastrointestinal tract break down drugs, so do the bacteria that normally live there. Drugs also interact with food and drink…in some cases reducing, but in other cases increasing the amount that gets absorbed. After being absorbed through the gut, drug molecules travel through the portal vein to the liver. Most of the work of drug metabolism is done in the liver by enzymes like the cytochrome P-450 system.

These forms can be classified into nanospheres and nanocapsules. Nanospheres are solid, monolithic spheres made of dense polymer matrix, wherein the active ingredient is dispersed, while nano-capsules creating reservoirs, made of polymer membrane contiguous the drug in solid or liquid form (Bucolo and Salomone, 2012). The drug absorption mechanism from nano-spheres or nano-capsules after their application to conjunctival sac includes dispersion of the drug and degradation of the polymer (Rathore, and Nema, 2009). The advantages of nanoparticles as an ophthalmic dosage form, rise corneal infiltration and a larger dissolution area, which enhances of the drug bioavailability when compared to conventional eye drops (Bucolo, and Salomone,

It is clear from Figure 9 that the conventional release system has some limitations. Frequent administration is required because of the short half-life[38,39]. However, the release rate of the controlled release system, can be kept at a expected level for a relatively long period of time. It can avoid drug plasma level fluctuations and stabilize plasma level[38]. In addition,

Systemic drugs, or analgesics, often include narcotics that are designed to dull the pain, while still keeping the patient alert and aware during delivery. Tranquilizers are also sometimes given in order to reduce anxiety, stress and nausea. Systemic drugs are often given through an intravenous (IV) line or as an injection into the muscle. This spreads the relief throughout the entire body rather than just the pelvic area.

When a prohormone or steroid is absorbed into the epithelial cell it is then partitioned (or directed) into either the portal vein or the lymphatic system. The process that determines this partitioning (choosing of one or the other disposition) is called “superlipophilicity”. Creating a system of delivery that will cause partitioning in the right direction is part of the equation, but not the whole picture.

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There are plenty of drugs that are targeting P-glycoprotein (p-gp), which is typically located in intestinal epithelial cells where drugs absorption occurring. The p-gp controls in and out of most of foreign substrates from the blood stream. It contributes to balancing out the concentration of drugs in the blood vain through reuptake process, especially efflux pump in this case. Therefore, this protein has been called as multidrug resistance because it is able to excrete the drugs into the lumen. Accordingly, the p-gp inhibitor has an important role for the drug bioavailability and transportation. As the p-gp inhibitor works in the vivo, the reuptake of drug will be decreasing which means decreasing the

# The technique used was to block the protein that transfers the drugs into the kidney, leaving the drug in the bloodstream. The method for that is mainly a probenecid injected (blocking the protein carrier) fifteen minutes before the injection of the substrate solution (such as penicillin G or estrone-3-subsrate). The estrone-3-substrate acts as a competitor for the protein carrier. The mice got injections through a vein in their tail.

Pharmacokinetics is term related to the ending of a substance that administered in a living organism. It consists of four phases and these are absorption, distribution, metabolism, and renal elimination, which referred to as ADME. There are two classes for pharmacokinetics: linear pharmacokinetics and non-linear pharmacokinetics. Linear pharmacokinetics of drug is a term refer to dose independent and concentration independent pharmacokinetics, in which pharmacokinetic parameters are constant when the drug concentration change. These parameters are half-life, clearance (CL), and volume of distribution at steady state (Vss). The pharmacokinetic phases like absorption, distribution, and elimination in dose independent pharmacokinetics are followed first order kinetics. In this condition, the changing in the drug dose results directly changing in the drug concentration in a body. In contract, non-linear pharmacokinetics of drug is known dose dependent, time dependent or concentration dependent pharmacokinetics. One or more of the pharmacokinetics parameters

It reverses the effects of drugs that have been administered parentally. This is not harshly the case with other routes of administration, e.g. oral and transdermal.