Drug delivery techniques

Alternatively, one interesting drug delivery technique exploits the active transport of certain naturally-occurring and relatively small biomacromolecules across the cellular membrane. For instance, the nuclear transcription activator protein (Tat) from HIV type 1 (HlV-1) is a 101-amino acid protein that must interact with a 59-base RNA stem-loop structure, called the traus-activation region (Tar) at the 5 end of all nascent HlV-1 mRNA molecules, in order for the vims to replicate. HIV-Tat is actively transported across the cell membrane, and localizes to the nucleus [28]. It has been found that the arginine-rich Tar-binding region of the Tat protein, residues 49-57 (Tat+9 57), is primarily responsible for this translocation activity [29]. 

Chen L, Choo J, Yan B. The microfabricated electrokinetic pump a potential promising drug delivery technique. Expert Opin Drug Deliv 2007 4 119-129. 

The mid-spectrum region between chemical and biological agents includes substances such as bioregulators and toxins. These are all chemicals and almost all are not included in the Schedules - the two that are listed in Schedule 1 are ricin and saxitoxin. These mid-spectrum materials can now be readily produced in quantity -and for prohibited purposes, impurities are not a problem. The challenge to the Convention posed by such materials is further increased by the recent advances in drug-delivery techniques. 

For many drug delivery applications, the preferred method of delivery of the dosage form is by injection. For controlled release applications, the most frequently used approach to allow this method of administration is to prepare microspheres of the polymer containing the drug to be delivered. Several different techniques have been developed for the preparation of microspheres from polyanhydrides. 

Gardner, C. R., in Drug Delivery Systems Fundamentals and Techniques (P. Johnson and J. G. Lloyd-Jones, eds.), Horwood, Chichester, 1987. 

Patients switched from an MDI to a DPI should be counseled that the DPI requires a rapid and forceful inhalation as compared to the slow inhalation used for an MDI. Patients using a DPI should also be counseled not to exhale into the device, as it will cause a loss of dose or decreased drug delivery. Because delivery technique with inhalers deteriorates over time, the health care provider should take every opportunity to reinforce appropriate inhaler technique. 

Evaluate therapy on a regular basis. Assess the patient s control of asthma by evaluating symptoms, PEF diary entries, and rescue medication use. Step long-term control therapy up or down based on these parameters. Before stepping up therapy, reassess the patient s inhaler technique to assure appropriate drug delivery. 

Water-soluble polymers can also be used as aqueous solutions for drug delivery. Although the polymer is already dissolved, its increase in viscosity of the drug solution causes the drug to be retained somewhat longer in the desired application. This technique is common with ocular, nasal, and oral applications of drug solutions. 

L. Z. Benet, Input factors as determinants of drug activity route, dose, dosage regimen, and the drug delivery system, in Principles and Techniques of Human Research and Therapeutics, Vol. 3, (F. G. McMahon, Ed.), Futura, New York, 1974, pp. 9-23. 

The degradation of proteins in the solid state occur to a lesser extent and typically via different mechanisms than those that occur in solution [109,110]. Lyophilization is currently the more common technique in the manufacture of dried therapeutic proteins however, there is increasing interest in the use of spraydrying, owing to the unique physical nature of the spray-dried powder and its potential usefulness in protein drug delivery. 

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