Sustained Drug Delivery

S.E. Zale, DRUG DELIVERY Sustained Delivery of Proteins for Novel Therapeutic Products. Science, 1998. 281(5380) ... 

Capsulation Controlled drug delivery Sustained drug release... 

J. R. Robinson, ed.. Sustained and Controlled Kelease Drug Delivery Systems, Marcel Dekker, Inc., New York, 1978, p. iii. 

Pitt, C. G., Jeffcoat, A. R., Zweidinger, R. A., and Schindler, A., Sustained drug delivery systems. I. The permeability of poly(e-caprolactone), poly(DL-lactic acid), and their copolymers, J. Biomed. Mater. Res., 13. 497-507, 1979. 

YoUes, S., and Sartori, M. F., Degradable polymers for sustained drug release, in Drug Delivery Systems (R. L. Juliano, ed.), Oxford University Press, New York, 1980, pp. 84-111. 

A number of the water-soluble polymers also have adhesive properties which are being extensively evaluated for drug delivery (9). These polymers will adhere to the mucous coating in the gastrointestinal tract, the nose, and the mouth to delay passage and sustain drug release. Those polymers with the best adhesive properties are those with hydroxyl and carboxyl groups. Table II lists some of the bioadhesive polymers and their adhesive properties. 

In the previous paper (7) we have described the synthesis, characterization, and certain diffusional characteristics of poly(N V-methylacrylamide)-l -polyisobutylene amphiphilic networks exhibiting a relatively high degree of swelling in both water and n-heptane. It was of interest to prepare further neutral amphiphilic networks of lower water swelling for sustained drug delivery systems. One candidate for this... 

With one exception, all the chapters from the third edition of Modern Pharmaceutics that appear in the fourth edition have been revised and updated. Many chapters were extensively updated, and some, such as the first and last chapters, were extensively rewritten. Due to the illness of Dr. Robinson, the chapter on sustained and controlled release drug delivery systems was updated with the assistance of Gil Banker, with Dr. Robinson s approval. 

Other than possibly for the insensible perspiration they absorb, transdermal patches tend to operate as thermodynamically static systems, meaning as com-positionally fixed systems, from the moment they are applied until their removal. Marketed ethanol-driven estradiol and fentanyl patches are exceptions because they meter out ethanol and drive it into the stratum corneum to propel the absorption process. Compositional steadfastness is still the rule, however, and it is this feature that bestows the zero-order delivery attribute on the ordinary transdermal patch. Drug is present within the patches in reservoir amounts whether or not the reservoir compartment is easily distinguished, for there must be enough drug to sustain delivery over the full course of patch wear. 

Y Raghunathan, L Amsel, O Hinsvark, W Bryant. Sustained-release drug delivery system I coated ion-exchange resin system for phenylpropanolamine and other drugs. J Pharm Sci 70 379-384, 1981. 

W Im-Emsap, GA Brazeau, JW Simpkins, R Bodmeier. Sustained drug delivery of 17-/1 estradiol from injectable biodegradble in situ forming microparticles (ISM) system. AAPS PharmSci Supplement 2(4), AAPS Annual Meeting Abstracts, 2000. 

M El-Samaligy, P Rohdewald. Triamcinolone diacetate nanoparticles, a sustained release drug delivery system suitable for parenteral administration. Pharm Acta Helv 57 201, 1982. 

Sustained- and Controlled-Release Drug-Delivery Systems... 

Before treating the various classes of sustained- and controlled-release drug-delivery systems in this chapter, it is appropriate to note that drug delivery may be incorporated in other chapters where the various classes of drug products and routes of administration are discussed. In addition, the reader is referred to Chapter 14 on target-oriented drug-delivery systems. 

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. 

In addition, biodegradable nanoparticles for sustained release formulations to improve site-specific drug delivery has also been reviewed [98]. 

Controlled and sustained drug delivery has recently begun to make an impression in the area of treatment of dental diseases. Many researchers have demonstrated that controlled delivery of antimicrobial agents, such as chlorhexidine [128-130], ofloxacin [131-133], and metronidazole [134], can effectively treat and prevent periodontitis. The incidence of dental caries and formation of plaque can also be reduced by controlled delivery of fluoride [135,136]. Delivery systems used are film-forming solutions [129,130], polymeric inserts [132], implants, and patches. Since dental disease is usually chronic, sustained release of therapeutic agents in the oral cavity would obviously be desirable. 

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],... 

---