Drug Delivery Systems 5A. Oral Drug Delivery

Abstract

The two main advantages of controlled drug delivery systems are: maintenance of therapeutically optimum drug concentrations in the plasma through zero-order release without significant fluctuations; and elimination of the need for frequent single dose administrations. The oral and other therapeutic systems in human use have validated the concept that controlled continuous drug release can minimize the daily dose of a drug required to maintain the required therapeutic effect, while minimizing unwanted pharmacological effects. By minimizing patient intervention, a design feature of therapeutic systems, compliance is automatically enhanced. Oral drug delivery systems, in particular, have required innovation in materials science to provide materials biocompatible during prolonged contact with body tissues, bioengineering to develop drug delivery modules, and clinical pharmacology for elucidation of drug action under conditions of continuous controlled drug administration. Recent work in advanced oral delivery has been primarily focused on liposome technology and the concept that substances that are normally destroyed by the stomach can be protected long enough before they could be absorbed downstream. For cost and patient convenience, oral delivery certainly would be an attractive method. The nature of biologic substances, however, with their unique technical problems, will probably limit greatly those that can be delivered orally. Besides, where delivery rate control is critical, oral delivery, even when possible, would probably be insufficiently precise. Oral delivery would also limit the substance to bloodstream delivery to the disease site. Even so, oral controlled drug delivery systems will likely find primary usefulness in specific carefully controlled therapies and prophylactic situations with due regard for drug interactions. This system represents a potentially very significant therapeutic modality. These delivery systems will find usefulness primarily in certain well-defined and well-controllable areas with due regard for individual patient variations. The purpose of the present article is to review oral controlled-release drug delivery systems, with particular emphasis on the practical aspects of testing and fabricating these systems and the underlying mechanisms by which control over drug release rate is accomplished.

Inorganic delivery vector for intravenous injection

“…Release of the drug from the polymer is generally based upon release by diffusion, bioerosion, degradation or swelling. Some are regulated by the production of osmotic pressure [1,2]. However, more recently, some researchers have focused on the use of nanoceramic particles as gene or drug delivery carriers [3].…”

Diltiazem Hcl: Evaluation of Its Presence in Bangladesh

“…This can avoid the "peak and valley" effect of oral or injectable therapy and can enable more controlled effective treatment by delivering drugs at a steady rate into bloodstream over an extended period of time. It also reduces the dosage-related side effects because the amount of drug delivered into the biological system in a very controlled manner and avoids first-pass metabolism 39,40 . Various types of preparation and methods employed in the preparation of transdermal drug delivery systems are discussed in the literature 41,42 .…”

Challenges of Drug Delivery

“…These characteristics include (i) an ability to be produced easily and on a large scale, (ii) applicability to a wide range of drugs, (iii) physiological stability, (iv) biocompatibility, and (v) acceptability by regulatory committees, such as the U.S. Food and Drug Administration (FDA) [3].…”

“…In addition to polymer alone, receptor-specific ligands can be grafted to either the conjugated polymer or the drug itself, which results in site-specific accumulation of the therapeutic [3]. Known as active targeting, this is an effective method to reduce nonspecific uptake and improve efficacy.…”