Term
| transdermal drug delivery systems |
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Definition
| -topically administered long acting medicated patches designed for systemic effects |
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Term
| nicotine approved for OTC |
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Definition
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Term
| advantages of transdermal systems |
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Definition
-avoid GI, absorption, drug interactions
-substitute for oral route
-avoids first pass
-multi day therapy for single application
-extends the activity of drugs with short half lives (reservoir)
-provides capacity to terminate drug effects rapidly
-rapid id of medication in emergency |
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Term
| limitations of trandermal systems |
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Definition
-not for all drugs (relatively potent and small MW)
-limited time patch can be affixed
-variable absorption
-variable adhesion
-skin rashes and sensitivity
-bacterial and enzymatic metabolism under the patch
-complex technology/high cost |
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Term
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Definition
-must use large drug load
-80-90% of drug is unused
-zero order kinetics
-Fick's Law of diffusion (passive)?
-skin or device may be rate limiting for absorption |
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Term
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Definition
-passes through skin layers to the vascular area for absorption into general absorption
-must pass through stratum corneum (semi permeable, rate limiting), epidermis, dermis |
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Term
| factors affecting absorption |
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Definition
-drug concentration
-skin hydration
-larger SA
-drug should have greater attraction to skin (penetrate better in unionized forms)
-MW preferred below 400 (400-800 can pass too)
-apply to thin stratum corneum
-more time in contact = greater absorption |
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Term
| percutaneous absorption enhancers |
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Definition
-chemical skin penetration enhancer-by reversibly damaging or altering stratum corneum
-increased hydration of stratum corneum and change in structure of lipids and lipoproteins
-ex. DMSO, propylene glycol, sodium laurel sulfate |
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Term
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Definition
-delivery of charged chemical compound across skin membrane using and applied electric field
-ex. IONSYS (fentanyl) |
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Term
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Definition
-high frequency ultra sound that disrupts the integrity of the stratum corneum
-designed for use with biologically active peptides |
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Term
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Definition
-oxygen activated heating system with patch
-increase drug absorption
-SYNERA (lidocaine and tetracaine)
(numbing for shots) |
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Term
| layers of transdermal system |
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Definition
-occlusive backing (protection/hydration)
-drug reservoir or matrix
-membrane to control drug delivery (some)
-adhesive layer
-liner (removed before patch is applied) |
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Term
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Definition
-single layer drug in adhesive
-multi layer drug in adhesive
-drug reservoir
-drug matrix |
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Term
| single layer drug in adhesive |
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Definition
-drug contained in adhesive
-rate of drug release is dependent upon penetration of skin |
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Term
| multi layer drug in adhesive |
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Definition
-drug is contained within adhesive
-contains a membrane between or layer creating a reservoir system |
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Term
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Definition
-drug is dispersed within a polymer matrix (helps control rate of diffusion, stratum corneum becomes rate limiting step)
-drug matrix layer placed between frontal and backing layer |
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Term
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Definition
-(pouch)
-liquid or suspension
-membrane controlled system |
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Term
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Definition
-skin to recover
-can resuse site after 1 week |
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Term
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Definition
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