Patches Flashcards

Question

How does Cystic Fibrosis Indicator System (CFIS) “Sweat Sticker” work?

Answer 1

High concentration of Na and Cl in the sweat of patients with Cystic Fibrosis --> pathogenetic defect. A small circular patch, collects sweat and chloride ions as a screening test for cystic fibrosis. In the patch is a chloride-complexing chemical; it produces a color change when the chloride concentration is above 45mM

Answer 2

It is a screening test NOT monitoring test (Identifies the presence of the disease not for regular monitoring of the condition).

Answer 3

MEASURES glucose in the subcutaneous tissue not the blood Limitation --> rtCGM systems, except for Dexcoms current G6 system, have to be manually calibrated to BG levels approximately 2 times per day

Answer 4

Lancet free glucose monitoring system Also a continuous glucose monitoring system

Answer 5

Dexcom is real time (rtCGM systems) and Libre is intermittent scanning (iscCGM system) Dexcom is compatible with insulin pumps and has a buildt in alarm when glucose is at or below 3.1 mmol/L (only alert that cannot be turned off)

Answer 6

epidermal and dermal drug absorption

Answer 7

interfacing with dermis

Answer 8

maximize drug penetration to the dermis BUT minimized systemic absorption

Answer 9

Delivery and maintenance of therapeutic levels of drug in the systemic circulation over a long period of time with the most convenience to the patient

Answer 10

The major limitation to transdermal drug delivery (TDD) is the skin itself. Stratum corneum (rate-limiting barrier) PLUS Metabolically active layers of the skin have biotransformation capacity. However, it is considerably lower than in the gut or liver.

Answer 11

Avoids gastrointestinal drug absorption difficulties Is an alternative to oral or parenteral administration Avoids first-pass hepatic metabolism Multi-day therapy can be achieved by a single application Extends the activity of drugs with short half-lives Easy to terminate the drug effect Smooth plasma concentration of drugs without significant fluctuations for long periods Ease of self-administration and improved patient compliance | 8

Answer 12

Unsuitable for drugs which sensitize the skin/sensitivity of skin for excipients (rashes, local irritation, erythema, or contact dermatitis.) Only potent drugs are suitable candidate for TDSs as small doses can be delivered via this dosage system Highly dependent on patient factors Very few drugs can be delivered at a viable rate using this route due to low permeability Inter and intra-individual variability (regional skin site, skin age, changes in peripheral circulation etc.)

Answer 13

Prepare skin to remove any dirt, lotions, oils, or powders --> affects adhesion If you do tear or cut the patch, don’t use it --> unpredictable drug response Using the palm of your hand, press down on the patch. The patch should be smooth, with no bumps or folds --> loose fitting will affect drug penetration You may trim the hair if needed BUT avoid shaving the area of application -->increased chances of irritation; broken skin may pre-dispose higher drug exposure (REMEMBER drugs in patches are potent) Don’t use a heating pad on your body where you’re wearing a patch  increase absorption kinetics ALWAYS MAKE SURE TO REMOVE THE OLD PATCH BEFORE WEARING A NEW ONE  Serious risk of overdosing Dispose off the old patch after first folding it in half with the sticky sides pressed together  reservoir will still have some drug content

Answer 14

Drug with high potency (dose requirement of less than 25mg/day) Low molecular weight Lipophilic Short half-life Low melting point (correlates with good solubility within the reservoir) High skin permeability Non-irritating and non-sensitizing to skin Low oral bioavailability Low therapeutic index (i.e. requires tight control of plasma levels) Pretty Little Liars Saved Me, not one teenager perservered

Answer 15

Reservoir type Matrix type Drug-in-adhesive (DIA) type: single-layer DIA multilaminate DIA Dot-matrix

Answer 16

Separate Drug compartment: contains drug solution or suspension in a reservoir space Drug delivery control: Membrane control the kinetic of release = controls the passage of drug and other formulation excipients

Answer 17

drug dissolved/suspended in a solvent e.g. ethanol liquid excipients penetration enhancer

Answer 18

Drug release from reservoir systems normally follow zero-order kinetics (proceed at a constant rate irrespective of concentration)

Answer 19

Location of adhesive layer: mostly a continuous layer on the membrane (face adhesive) or in a concentric configuration on the perimeter of the patch

Answer 20

Adhesive and drug or adhesive and excipient interactions/incompatibilities can occur Vulnerable to burst release Reasons: rupture of the membrane due to material defect, wear, inadvertent puncture

Answer 21

Trans-derm Nitro Androderm

Answer 22

Rate controlling is the matrix no rate controlling membrane. In the reservoir patch, the membrane limits the rate of drug delivery; in the matrix system, it is the formulation of the drug/polymer matrix

Answer 23

Drug compartment contains drug solution or suspension form in a matrix Most simple design: a drug containing semisolid disc is held in contact with the skin by an adhesive tape Drug delivery control - Rate controlling matrix and the stratum corneum (first order) NO membrane

Answer 24

drug dissolved/suspended in a semisolid penetration enhancer

Answer 25

A first-order reaction rate depends on the concentration of the drug in the matrix and the stratum corneum.

Answer 26

Matrix can itself act as an adhesive layer. It can also be a separate layer

Answer 27

The protective overlay maybe mistaken for the part to be applied on the skin (unlikely if patient is properly trained/can also be avoided via clear labeling) Total patch surface area can be a lot larger than the actual drug delivery surface (BUT new systems have overcome this limitation by making system sizes equivalent to effective release area of the patches)

Answer 28

Exelon (Alzheimer’s disease) Sandoz- Fentanyl patch (pain management)

Answer 29

Contains the drug dissolved in an adhesive formulation Represent the ‘state-of-the-art’ in transdermal delivery system design Extremely comfortable Patch is very thin Maximum utilization of surface area of the patch

Answer 30

drug dissolved in a pressure sensitive adhesive (PSA) e.g. PIB (polyisobutylene), silicone or acrylate type adhesive composition must be customized for each drug

Answer 31

Drug delivery control - Rate controlling adhesive and the stratum corneum First-order kinetics of drug release (release proportional to drug concentration within the adhesive)

Answer 32

Location of adhesive layer: entire surface of the patch – maximum utilization of surface area for drug release the multi-laminate design can be used where more drug can be released through the membrane in the upper DIA compartment into the lower DIA compartment

Answer 33

The first-order release characteristics (when drug concentration in adhesive falls, constant drug delivery profile is difficult to maintain) – to overcome this problem multi-laminate DIA

Answer 34

Estradot (Management of post menopausal symptoms) EVRA (Birth control patches) NEUPRO® (rotigotine transdermal system) | Dopamine Agonist first and only Parkinson's "patch“

Answer 35

NOT all TDS for same drug will have same mechanism e.g. nitroglycerin patches Transderm Nitro (reservoir) while Nitro-Dur and Mylan-Nitro patch (adhesive type).

Answer 36

Acrylic: to hold the drug in high concentration Semisolid suspension; the microscopic drug-in acrylic droplets evenly dispersed in the non-compromised silicone adhesive

Answer 37

drug dissolved in acrylic Adhesive: silicone polymer

Answer 38

Dot-matrix technology (daily dose = 0.025 mg per day)

Answer 39

Confusion factor --> many different patch designs, dosage strength, frequency of administration, shape, size, color, site of administration (we discussed interchangeability …) Improper application (Imporant to tell patient to follow package inserts carefully) peeling not just the protective layer but also the adhesive overlay should be applied directly on the skin (a patient had 4 patches stuck on top of each other) – so important to tell them to REPLACE the old one. It also increases the risk of overdosing because of the left over medication. must remove the protective liner location where the patch should be applied THAT is very critical especially for the hormone patches. clear patches are difficult to find on the body when its time to remove them (e.g. by caregivers) Nomenclature issues mg/h, mg/day, mcg/h, mg/day/week TTS =Transdermal Therapeutic System (NOT Tuesday, Thursday, Saturday) Dosing intervals ((dosing regimen to be defined - frequency of application) for example fentanyl patches needs to ne changed EVERY 3 days. may be daily, every 3 days, twice weekly, weekly, every 3 weeks etc. the longer the time between patches the greater the risk for forgetting where the old patch is Pediatric patch issues cutting patches for a pediatric patient – not possible with reservoir types but maybe done with matrix or DIA types Safe storage It may be appealing for young children.

Answer 40

NOven - Daytrana --> methylphenidate

Answer 41

The main force used to drive substances across the stratum corneum is the electrical driving force, where there is charged particle movement via electrophoresis. This way, a persistent low-voltage current enables the diffusion of substances across the stratum corneum. An electrical current can control drug delivery rate under the control of either a microprocessor or the patient.

Answer 42

IONSYS (fentanyl iontophoretic transdermal system) Fentanyl hydrochloride for pain control Extended Release Electrically Controlled and Patient-activated Used for the treatment of hospitalized patients. Designed to deliver a 40-mcg dose of fentanyl (equivalent to 44.4 mcg of fentanyl hydrochloride) over a 10-minute period upon each activation of the dose button