Conventional drug delivery

Lang, J. C. (1995), Ocular drug delivery conventional ocular formulations, Adv. Drug Deliv. Rev., 16(1), 39-43. 

Reprinted from Advanced Drug Delivery Reviews, Vol. 16, John C. Lang, Ocular drug delivery conventional ocular formulations, Pages 39-43, 1995, with permission from Elsevier Science. 

Historically, the oral route of administration has been used the most for both conventional and novel drug-delivery systems. There are many obvious reasons for this, not the least of which would include acceptance by the patient and ease of administration. The types of sustained- and controlled-release systems employed for oral administration include virtually every currently known theoretical mechanism for such application. This is because there is more flexibility in dosage design, since constraints, such as sterility and potential damage at the site of administration, axe minimized. Because of this, it is convenient to discuss the different types of dosage forms by using those developed for oral administration as initial examples. 

Rapid-release products are another class of con-trolled-release drug-delivery systems of growing interest to pharmaceutical scientists. For this type of product rapidity of response is the key parameter. If a conventional non-controlled-release product gives the therapeutic response in one hour, a rapid-release product might be designed so as to yield such a response in 20 minutes. 

In addition to the detection methods described hitherto, binding and uptake of targeted drug delivery systems can be determined by flow cytometric analysis. Similar to conventional fluorimetric techniques, flow cytometry... 

Drug-delivery systems are essentially specialized dosage forms developed to overcome the limitations of conventional dosage forms, such as simple tablets, capsules, injectable solutions, etc. Some of the reasons behind the development of oral DDSs are listed below ... 

In recent years, drug delivery technologies have grown extensively that go beyond conventional oral dosage forms. For example, intravenous, transdermal, and implant technologies are widely used for sustained drug delivery over increased periods of time. The type of drug, its characteristics, and the intended indication determine the mode of delivery. 

Over the past 20 years, our laboratory has played a major role in the development of liposomal systems optimized for the delivery of conventional drugs, almost all of which are encapsulated by pH-gradient techniques. Our initial studies led to the development of several liposomal drug delivery systems in which uptake was driven by the citrate method of generating pH gradients (15,21-23,27,54—58). This was followed by the development of new... 

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