Oral drug delivery bioavailable dose

Sustained- and controlled-release devices for drug delivery in the vaginal and uterine areas are most often for the delivery of contraceptive steroid hormones. The advantages in administration by this route—prolonged release, minimal systemic side effects, and an increase in bioavailability—allow for less total drug than with an oral dose. First-pass metabolism that inactivates many steroid hormones can be avoided [183,184],... 

Absorption is the transfer of a drug from its site of administration to the blood stream. The rate and efficiency of absorption depend on the route of administration. For intravenous delivery, absorption is complete, that is, the total dose of drug reaches the systemic circulation. Drug delivery by other routes may result in only partial absorption and thus lower bioavailability. For example, the oral route requires that a drug dissolve in the gastrointestinal fluid and then penetrate the epithelial cells of the intestinal mucosa disease states or the presence of food may affect this process. 

Clonidine is well absorbed after oral administration, with bioavailability -100%. The peak concentration in plasma and the maximal hypotensive effect are observed 1-3 hours after an oral dose plasma concentrations of clonidine and its pharmacological effects correlate well. The elimination tj of the drug ranges from 6-24 hours (mean -12 hours). About half of an administered dose appears unchanged in the urine the tj of the drug may increase with renal failure. A trans-dermal delivery patch permits continuous administration of clonidine at a relatively constant rate for a week 3-4 days are required to reach steady-state concentrations in plasma. When the patch... 

Polymeric microparticles have been studied and developed for several years. Their contribution in the pharmacy field is of utmost importance in order to improve the efficiency of oral delivery of drugs. As drug carriers, polymer-based microparticles may avoid the early degradation of active molecules in undesirable sites of the gastrointestinal tract, mask unpleasant taste of drugs, reduce doses and side effects and improve bioavailability. Also, they allow the production of site-specific drug targeting, which consists of a suitable approach for the delivery of active molecules into desired tissues or cells in order to increase their efficiency. 

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