Drug delivery systems types

The lung comprises about 40 different cell types, amongst which type I and type II alveolar epithelial cells are the major types targeted by pulmonary drug delivery systems. Type I cells play an important role in the absorption process of proteins, while type II cells produce surfactant, regulate the immune response, and serve... 

Polyphosphazenes can be considered as biomaterials in several different ways, depending on the type of utilization one can predict for these substrates. In this regard, we will consider three different topics concerning water-soluble POPs and their hydrogels, bioerodible POPs for drug delivery systems and for tissue engineering, and the surface implications of POP films. 

Because these types of polymeric matrix systems are the simplest to design and the easiest to obtain approval by the Food and Drug Administration, they have been the most extensively studied in the past two decades. Numerous polymers have been evaluated for these types of drug delivery systems and although it would be impractical to present each of these polymers and its specific application to drug delivery, this chapter will review in general the types of polymers used as matrices for drug delivery (1-4). 

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. 

Despite the evidence for the cytotoxicity of CNTs, there are an increasing number of published studies that support the potential development of CNT-based biomaterials for tissue regeneration (e.g., neuronal substrates [143] and orthopedic materials [154—156]), cancer treatment [157], and drug/vaccine delivery systems [158, 159]. Most of these applications will involve the implantation and/or administration of such materials into patients as for any therapeutic or diagnostic agent used, the toxic potential of the CNTs must be evaluated in relation to their potential benefits [160]. For this reason, detailed investigations of the interactions between CNTs/CNT-based implants and various cell types have been carried out [154, 155, 161]. A comprehensive description of such results, however, is beyond the scope of this chapter. Extensive reviews on the biocompatibility of implantable CNT composite materials [21, 143, 162] and of CNT drug-delivery systems [162] are available. 

Araya H, Tomita M, Hayashi M (2006) The novel formulation design of self-emulsifying drug delivery systems (SEDDS) type O/W microemulsion III The permeation mechanism of a poorly water soluble drug entrapped O/W microemulsion in rat isolated intestinal membrane by the Ussing chamber method. Drug Metab Pharmacokinet 21 45-53. 

R. Lipp, H. Laurent, C. Gunther, J. Riedl, P. Esperling, U. Tauber, Prodrugs of Gesto-dene for Matrix-Type Transdermal Drug Delivery Systems , Pharm. Res. 1998,15, 1419 -1424. 

Noncovalent interactions play a special role in synthetic procedures used to assemble various types of supramolecular species. These syntheses rely on the stabilization provided by non-covalent interactions between recognition sites incorporated within precursors. Various types of non-covalent interactions can be used as a recognition motif utilized to guide the synthesis.Targeted synthesis of macro- and supramolecular structures of various sizes, shapes, and functionality has now become possible. Supramolecular chemistry offers incredible applications in various fields such as medicinal chemistry (drug delivery systems),host-guest chemistry,catalysis,and molecular electronics. ... 

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