Skin adhesive patches

V.a.1.2. Transdermal preparations. Adhesive patches applied to the skin can be used to deliver oestrogens transdermally, using either a reservoir of liquid or an oestradiol-containing matrix. These systems deliver adequate amounts of oestradiol to maintain plasma levels within the normal range for 24 hours, and some preparations now provide transdermal progestagen also, thus avoiding the need for additional tablets to be taken for part of the cycle. 

Poor compliance with traditional patching Hypersensitivity or skin allergies resulting from adhesive patch... 

A transdermal delivery system has been developed for prevention of motion sickness and vomiting, using an adhesive patch for postauricular application the drug is released at a uniform rate for 72 hours. The adverse effects of this formulation are qualitatively typical of those reported for the oral and parenteral formulations of hyoscine and its congeners, although comparative studies suggest that the incidence is reduced with transdermal administration. Nevertheless, adverse effects involving the central nervous system, vision, bladder, and skin have been described, as have withdrawal symptoms after the patch is removed. 

Because of their excellent adhesion and physiological safety, povidone K 30 and povidone K 90 are used as adhesives on the skin or mucous membranes. Examples include transdermal systems, oral adhesive gels, buccal adhesive patches or tablets [511,546,547,559,573,574], contact gels for electrocardiograph or electroencephalograph electrodes and adhesives for colostomy bags. Table 107 shows a formulation for a contact gel developed on a laboratory scale for ultrasonic scanning. 

Skin patches are adhesive patches which contain a reservoir of the drug to be administered. The drug slowly passes from the patch through the skin and into the bloodstream. They are commonly used in hormone replacement therapy, nicotine replacement therapy, pain relief, relief of symptoms of angina, motion sickness, birth control and in the treatment of attention deficit hyperactivity disorder (ADHD). 

The self-adhesive electrodes are patches wired to the patient through conductive flexible adhesive which holds the electrode in place, tightly against the skin. Adhesive electrodes are shown in Figure 14.6. They are disposable and are applied to the chest before the dehvery of shock. Adhesive electrodes are left in place for reuse in case subsequent shocks are needed. Electrodes are usually applied with both electrodes on the anterior chest as shown in Figure 14.7, or in an anterior-to-posterior position, as shown in Figure 14.8. 

Transdermal scopolamine is a muscarinic receptor antagonist used for the prevention of post-operative nausea and vomiting. It is supplied as a circular adhesive patch (0.2 mm thick and 2.5 cm ) applied to the post-auricular skin. Each patch contains 1.5 mg of the belladonna alkaloid programmed to continuously release in vivo approximately 1.0 mg over 72 hours. The patch consists of four distinctive layers. Going from visible surface to the surface adherent to the skin, these layers are (1) backing layer (2) drug reservoir of scopolamine (3) microporous polypropylene membrane that controls the rate of scopolamine delivery (4) adhesive contact surface with the skin. 

Longer duration of use - 7 days (versus 3 days for fen-tanyl patches) smaller patch size improves patient comfort/compliance (about 1/5 current fentanyl patch size) improved skin adhesion (versus fentanyl patches) improvement in skin irritation amongst other patch technology prolonged analgesic delivery system steady duration of analgesia. 

A novel patch approach of sweat collection has been introduced recently for testing of drugs. Although not yet cleared for drug-testing purposes, the adhesive patch is approved for collecting perspiration, and may eventually prove to be a viable technique. The device consists of an adhesive layer on a 2 x 3-in. transparent film that adheres to the skin. The patch contains an adsorbent pad in its center that collects sweat as it exits the body. The device is intended to be worn for up to 2 weeks at a time, after which the collected sweat residue is removed by a simple extraction procedure. So far, the sweat patch has been effective in monitoring low levels of cocaine and heroin. 

The capacity of the skin to absorb lipid-soluble chemicals is both a blessing and a curse. Transdermal medicated adhesive patches, for example, take advantage of the capacity of the skin to absorb small lipophilic compounds in order to administer chemicals such as scopolamine, the anti-sea sickness drug, and nicotine. Unfortunately, urushiol, the active ingredient found in poison ivy, poison oak, and poison sumac, also takes advantage of the skin s capacity to absorb small, lipophilic chemicals, and is absorbed via the dermal pathway. 

Absorption Cells comprising the outermost 0.25-0.40mm of the skin absorb oxygen from the environment. In addition, medicine can be administered through the skin using ointments or adhesive patches, such as a nicotine patch or iontophoresis. 

BGM systems need to ensure a reproducible mechanical interface between the measurement device and the test strip over the time of one measurement, which typically takes a few seconds. CGM systems need to do so over a time span of 6 to 14 days, while the system is worn by the patient during his daily routine which asks for different solutions of mechanical coupling and electrical coimections. CGM measurement devices need to be attached to the patient s skin via adhesive patches commonly used for transdermal applications [291-293]. BGM test strips do not require sterilization prior to use. CGM probes or CGM sensors need to be sterile prior to use since they are inserted subcutaneously. Materials used for constructiOTi of the implants need thus to resist sterilization conditions, and the combinatiOTi of materials needs to meet ISO 10993 biocompatibility requirements. 

This medical device is a small, programmable pump that administers insulin via the infusion set, consisting of a cannula and a needle. It is designed to be used for insulin pump therapy (continuous subcutaneous insulin infusion, CSll). The patch pump is a variant that combines the infusion set with the pump in a common housing (usually referred to as the pod). This unit is applied to the skin as an adhesive patch and replaced after two or three days. It is controlled by a separate unit (the personal diabetes manager, PDM) with a wireless link to the pod. Patch pumps were introduced in the USA around 2007 and have been available in Europe since mid-2010. The MID is the electrical chassis for the single-use insulin management system (Fig. 9.7). 

Transdermal patches arc applied to the skin. The drug is mixed with the adhesive for the patch, and so it lies next to in readily absorb many chemicals and so uch as nitroglycerin (for heart disease),... 

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