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Transit time for food through the digestive tract: Mouth
1 minute
Transit time for food through the digestive tract: Esophagus
4-8 seconds
Transit time for food through the digestive tract: stomach
2-4 hours
Transit time for food through the digestive tract: small intestine
3-5 hours
Transit time for food through the digestive tract: Colon
10 hours to several days
Modified oral dosage forms are pharmaceutical formulations that are designed to alter the ____, ____, and/or _____ of drug release in the gastrointestinal (GI) tract.
rate, time, location
Unlike immediate-release (IR) forms, modified-release (MR) systems offer controlled drug delivery, improving the therapeutic ______ and patient _______.
outcome, experience
Modified dosage forms aim to deliver the (minimum/maximum) amount of drug necessary to the site of action to produce the desired therapeutic response
maximum
Modified dosage forms aim to deliver the drug at an optimal rate to ______ the beneficial response and _______ unnecessary drug exposure (minimize side effects)
maximize, minimize
Some other modified- release dosage forms and drug delivery systems are also described, including ______, _______, ________, and _______ products
ocular, parenteral, subdermal, and vaginal
Drugs that are long lasting and only require a once a day oral dose are formulated in the conventional manner in __________ dosage forms
immediate release
Some drugs are inherently long lasting and require only once-a-day oral dosing to maintain adequate drug ________ and desired ________
plasma levels, therapeutic effect
What is the half life of drugs that are rapidly cleared by the body and require multiple doses per day?
t1/2= 30 min
Multiple daily dosing is inconvenient for the patient and can result in __________, _________, and _______ with the regimen
missed doses, made-up doses, and noncompliance
When conventional immediate-release dosage forms are taken on schedule and more than once daily, they cause sequential therapeutic blood level ____ and _____ (troughs) associated with the taking of each dose
peaks, valleys
What does SR/ER mean? Are they the same thing?
Sustained release, Extended release, YES they are the same
What are 3 benefits of patients using SR/ER?
- Reduced dosing frequency. Increase patient compliance especially for chronic diseases (e.g., hypertension, diabetes)
- Maintaining therapeutic levels
- Reduced side effects
Delayed release (DR)/ Enteric coated (EC) are drugs that delay drug release until it reaches a specific part of the _______
GI tract, typically the intestine
Why are DR/EC used?
- Bypass the stomach: protects the drugs that are unstable or degraded by gastric fluid
- Protect the stomach lining: NSAIDs, aspirin irritates the stomach
- Targeted release: release drug in a specific part of the GI tract for better absorption or achieve local effect (e.g., treatment of Crohn's disease, ulcerative colitis)
__________: To release a drug after a specific period (not location-specific), often for"chronotherapy" (delivery of drugs based on biological rhythms)
Time controlled release systems
What is the rationale for using time controlled release systems?
Circadian Rhythm Synchronization: Some diseases (e.g., asthma, rheumatoid arthritis, and hypertension) exhibit time-dependent symptoms.Releasing a drug at a specific time of day can increase its effectiveness
Nighttime Effectiveness: Drugs that need to act during the night (like antihypertensives) can be designed to release several hours after ingestion
What is an example of time controlled release systems?
Verapamil: taken at bed time, reduce nighttime blood pressure spikes
_______: increase gastric retention time for drugs that are absorbed primarily in the stomach or upper intestine
Gastro Retentive systems
What is the rationale for Gastro-retentive systems?
- Prolonged Gastric Retention: Increases the residence time of the drug in the stomach, which is beneficial for drugs that have a narrow absorption window(only absorbed in the upper GI tract).
- Improved Absorption: Drugs with low solubility at high pH (e.g., basic drugs)benefit from a longer stay in the acidic gastric environment.
- Localized Action: Drugs intended to act locally in the stomach (e.g., fortreating H. pylori infection) are released at the site of action
What are examples of gastro retentive systems?
- Gebapentin ER
- Metformin GR
What is the rationale for colon targeted drugs?
- Treatment of colon-specific diseases
- Avoid systemic absorption
What are examples of Colon-targeted drugs?
- Mesalamin for ulcerative colitis
- Prenisolon colon-targeted for inflammation in Crohn's disease.
For zero order kinetics there is a ______ amount of remain/release
constant
For 1st order kinetics there is a constant _______ of drug remain/release
fraction
What is the release kinetics to plasma concentration profile?
Dosage form -> drug release -> Drug solution -> Drug absorption -> In circulation
Examples of immediate release systems include:
-Capsules
-Injections
Examples of first order release systems:
-Implantable devices
-Hydrogels
-Polymeric particles
Examples of zero order release systems?
-Osmotic pumps
-Actuated pumps
-Microchips
-Intravaginal rings
Which equation is associated with the first order kinetic?
Noyes Whitney
With the first order kinetic ______ is limited and there is no change in the _____ of the dosage form so the ______ remains constant
diffusion, shape, surface area
First order kinetic: Erosion
There (is/is not) a change in the shape of the dosage form
Is
What equation is used for the First order kinetic with Erosin
Hixson-Crowell
What are examples of drugs/things with there mechanism of release by erosion?
Hard candy/lollipop
First order kinetic: Erosion and Diffusion
_____ model is used
Higuchi
Simplest and most widely used. It describes the release of drugs from solid matrices where drug release is dependent on the square root of time.
First order kinetic: Erosion and Diffusion
What has a mechanism of release by erosion and diffusion?
most tablets
First order kinetic: Diffusion
Noyes Whitney equation
First order kinetic: Erosion
Hixson-Crowell equation
First order kinetic: Erosion and Diffusion
Higuchi model/equation
