Pharmaceutical Technologist - July 2008 - (Page 11)

The drug delivery market contraceptive patches that have been shown to have an efficacy similar to that of oral contraceptives. In the cardiovascular market, transdermal patches for angina and hypertension have also become available. Cancer pain medication (i.e., Fentanyl; Alza Corp., CA, USA) has been delivered transdermally and has witnessed increased uptake because of its convenience. Neurological and diabetes medications are other therapeutic drugs that are being investigated for transdermal drug delivery. Alternative transdermal technologies include: ● Jet Injectors. These handheld devices deliver high-pressure liquid (drug) through the skin. ● Iontophoresis. This uses an electric field to deliver drugs transdermally. The performance of this form of technology largely depends on drug properties such as polarity, valency and mobility. As a result of these factors, this technology is restricted to molecules less than 7000 . Vyteris Inc. (NJ, USA) launched a transdermal system based on this technology that was designed to deliver Lidocaine as a local anaesthesia. Alza’s Fentanyl also uses iontophoresis to deliver the drug transdermally. ● Sonophoresis. Ultrasonic waves are used to deliver drugs across the skin. Vaccines, insulin and low-molecular weight heparin have been successfully shown to be delivered using low-frequency ( 100 kHz) ultrasound waves. The first transdermal delivery using sonophoresis to be approved by FDA was SonoPrep (Sontra Medical Corp [now Echo Therapeutics] MA, USA), which is used for lidocaine administration for pain relief. Though this might be an effective technique for transdermal delivery, the need for circuitry and power (up to 1 W) may be a challenge. ● Chemical enhancers. Chemicals are used to permeate the skin and deliver drugs. These penetration-enhancing chemicals include water, surfactants, fatty acids, terpenes and solvents. Concerns have been raised regarding these chemicals causing irritation to the skin, but these reactions have been shown to be limited, and effectiveness can be enhanced by using iontophoresis and sonophoresis. Other techniques used for transdermal drug delivery include skin ablation and micro-needles. Nanotechnology Nanotechnology is one of the most promising areas in drug delivery and offers tremendous advantages including enhanced solubility, commendable bioavailability and controlled delivery of drugs. Better targeting is also possible through this method as drugs can be delivered to the specific cell, tissue or organ. Nanotechnology is best suited for delivering oncolytics during chemotherapy as it reduces systemic exposure and, therefore, drug toxicity. In addition, asthma and analgesic drugs are better absorbed when using this system. The nanotechnology-based drug delivery market is expected to garner revenues of $700–$800 billion (€441–504 billion) by 2015 as the market will be driven by the expanding horizon of therapeutic applications. Venture capital investments in nanotechnology drug delivery companies have also been increasing and have provided a positive spin to the market growth. Nanotechnology has been applied to several therapeutic areas. Oncology. The nanoscale devices employed for cancer therapy are silica-coated micelles, ceramic nanoparticles, dendrimers (spherical and branched polymers) and cross-linked liposomes. Research is focused on developing ‘smart’ nanodevices that are capable of detecting tumour cells in vivo, terminating the cells and producing the desired result. Such multifunctional nano-delivery structures are under research and scientists are using the naturally occurring virus capsule to establish chemical multifunctionality. In addition, there has been considerable progress in the development of synthetic multifunctional nanodevices. Dendrimers (1–10 nm spherical polymers) have shown immense multifunctional modularity. Several dendrimer-based nanostructures are now under development for treating various cancers. The advent of ‘nanoclinics’ has the potential to broaden therapeutic approaches to cancer using nanotechnology. Once the nanoclinics are absorbed by the target cells, magnetic resonance imaging can be used. Enough magnetic resonance heats up the entrapped ferric oxide molecules and kills the cancer cells. Nanotechnology is one of the most promising areas in drug delivery and offers tremendous advantages… Another approach to cancer therapy utilizing nanotechnology is the use of photo sensitizers in nanodevices. Photodynamic therapy uses light to generate reactive oxygen within the tumour cells once these nanodevices are absorbed by the cancer cells. One oncology drug that uses nanotechnology is Abraxane (paclitaxil) from Abraxis (CA, USA), which makes use of the drug nanoparticle albumin bound technology. Figure 1 The global market share of the various drug delivery systems in 2007. Occular and buccal 0.6% Pulmonary 18.5% Oral 51.7% Nasal 7.1% Injectibles 8.1% Liposomes 2.0% Transdermal 12.1% www.ptemagazine.com 11 http://www.ptemagazine.com

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Pharmaceutical Technologist - July 2008 Contents Industry Highlights Morpheus Market Watch Overcoming the Barriers The Tide of Change Eight Steps to Improved Water Efficiency Q&A

Pharmaceutical Technologist - July 2008

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