Pharmaceutical Formulations Quiz

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Questions and Answers

What is the primary purpose of coating drug particles in reservoir dissolution controlled formulations?

To allow for immediate drug availability after ingestion

To control the rate of dissolution and drug release (correct)

To increase the volume of the drug particles for easier handling

To enhance the solubility of the drug in water

According to the Noyes-Whitney equation, which factor does NOT directly influence the dissolution rate of a drug?

Thickness of the concentration gradient

Surface area of the solute particle

Diffusion coefficient of the solute

The molecular weight of the solute (correct)

How does microencapsulation impact the drug release process?

It ensures immediate release of the drug into the bloodstream

It protects the drug from environmental factors while delaying its release (correct)

It eliminates the need for a controlled dosage

It reduces the solubility of the drug in body fluids

Which of the following accurately describes microencapsulated particles?

They can encapsulate solids, liquids, or gases into particles ranging from 1–1000 μm Signup and view all the answers

What effect does the thickness of the coating have on drug release in reservoir dissolution formulations?

Thicker coatings decrease the rate of drug release Signup and view all the answers

What dual mechanism does Ambien CR utilize for drug release?

One layer releases drug immediately while the other releases it over time. Signup and view all the answers

What role does HPMC polymer play in Ambien CR?

It controls the release of the drug from the matrix. Signup and view all the answers

Which technique is NOT used to prepare drug-charged ion exchange resins?

Ultrasonic dispersion technique. Signup and view all the answers

What is the primary characteristic of the drug release from ion exchange resins?

It is controlled by the ionic environment within the resin. Signup and view all the answers

Why are ion exchange resins not suitable for skin applications?

They lack the necessary ions in the skin. Signup and view all the answers

In which part of the drug-exchange process do drug ions diffuse out of the resin?

After the ionic balance is established with the resin. Signup and view all the answers

What happens to the drug when the ion concentration changes in the solution?

It is exchanged and diffuses out of the resin. Signup and view all the answers

Which polymer is commonly used as a coating material for ion exchange resins?

Ethyl Cellulose. Signup and view all the answers

What distinguishes CPOP from traditional osmotic delivery systems?

It creates pores upon contact with water. Signup and view all the answers

Which feature of PPOP aids in the controlled release of the drug?

A push layer that expands upon water contact. Signup and view all the answers

What is the characteristic of the swelling agents used in osmotic tablets?

They exhibit swelling between 10 to 1000 times their original size. Signup and view all the answers

What are enteric polymers known for in terms of solubility?

They are insoluble below pH 6 and soluble above pH 6. Signup and view all the answers

Which statement about drug release in EOP and CPOP is correct?

CPOP needs drugs to be solubilized within its core for effective release. Signup and view all the answers

Which of the following polymers is NOT identified as an enteric polymer?

Polyethylene glycol (PEG) Signup and view all the answers

What does the push-stick osmotic pump (PSOP) technology combine?

Both immediate and sustained drug release phases. Signup and view all the answers

What distinguishes controlled release tablets from sustained release tablets?

Controlled release ensures drug release at a predetermined rate. Signup and view all the answers

In terms of drug solubility, which drugs are poor candidates for osmotic delivery systems?

Both highly and poorly soluble drugs. Signup and view all the answers

What is the benefit of using enteric coated tablets?

They prevent drug degradation in acidic environments. Signup and view all the answers

What is the role of the middle push layer in a sandwiched osmotic tablet (SOTS)?

It helps control the osmotic pressure for drug release. Signup and view all the answers

Which term is synonymous with controlled release?

Prolonged release Signup and view all the answers

What type of polymers are typically used as swelling agents in osmotic tablets?

Hydrophilic crosslinked or entangled polymers. Signup and view all the answers

What characterizes the drug release in controlled release dosage forms?

Release follows a zero order kinetics. Signup and view all the answers

In what way does sustained release differ from controlled release?

Sustained release can include an initial loading dose followed by slow release. Signup and view all the answers

Why are controlled release formulations considered beneficial?

They reduce the frequency of dosing. Signup and view all the answers

What is the main purpose of incorporating sodium bicarbonate and calcium carbonate in gastroretentive systems?

To create a gas-generating layer for buoyancy Signup and view all the answers

Which polymeric excipients are used as rate-controlling agents in the swellable triple layer system?

HPMC and polyethylene oxide Signup and view all the answers

What characteristic does the swellable floating system provide when it comes into contact with gastric fluids?

It forms a soft gelatinous mass Signup and view all the answers

Which of the following products utilizes HBS floating technology?

Topalkan Signup and view all the answers

In the context of gastroretentive systems, what is the primary benefit of prolonged gastric residence time?

Better patient adherence Signup and view all the answers

Which active ingredient is NOT part of the triple drug regimen for Helicobacter pylori–associated peptic ulcers?

Levodopa Signup and view all the answers

What type of drug release is associated with the hydrocolloid-based gastroretentive systems?

Sustained release Signup and view all the answers

What is a significant logistical challenge in treating diseases like malaria, TB, and HIV in rural populations?

Ensuring patient adherence to treatment Signup and view all the answers

Study Notes

Enteric Polymers

Enteric polymers are insoluble at pH 6 or below (stomach), but above pH 6 (intestine), they ionize and become soluble.
Examples of enteric polymers include:
- Cellulose acetate phthalate (CAP)
- Hydroxypropyl methyl cellulose phthalate (HPMCP)
- Hydroxypropyl methyl cellulose acetate-succinate (HPMCAS)
- Polyvinyl acetate phthalate (PVAP)
- Methacrylic acid copolymers (Eudragit ® NE 30 D, L100, S100)
Tablets coated with enteric polymers are called Enteric Coated Tablets.

Controlled Release Tablets

Controlled release tablets are designed to release medication at a specific rate and time for therapeutic effect.
Controlled release, prolonged release, sustained or slow release, and long-acting, are synonymous with extended release.
Controlled drug delivery systems release the drug at a predetermined rate for a set time, aiming for zero-order release (consistent rate, regardless of concentration).

Sustained Release Tablets

A sustained-release dosage form releases an initial dose for immediate effect and then releases the remaining portion slowly to maintain therapeutic levels for an extended duration.
Sustained release does not necessarily mean controlled release.

Controlled Release vs. Immediate Release

MEC (minimum effective concentration): The lowest concentration of medication needed for a therapeutic effect.
MTC (minimum toxic concentration): The lowest concentration of medication that causes toxic effects.
Therapeutic Window: The range of drug concentrations between MEC and MTC, where the drug is effective and safe.
Half-life: The time taken for the body to eliminate half of the drug from the bloodstream.

Why Controlled Release?

Controlled release formulations offer advantages over immediate release formulations, such as:
- Reduced dosing frequency
- Improved patient compliance
- More consistent therapeutic levels
- Reduced side effects

Drug Dissolution

Noyes-Whitney equation describes the rate of drug dissolution:
- dm/dt: Solute dissolution rate (kg/s)
- m: Mass of dissolved material (kg)
- t: Time (s)
- A: Surface area of the solute particle (m2)
- d: Thickness of the concentration gradient (m)
- D: Diffusion coefficient (m/s), related to solvent viscosity
- Cs: Particle surface concentration (saturation) (kg or moles/L)
- Cb: Concentration in the bulk solution (kg or moles/L)

Reservoir Dissolution Controlled Formulation: Coating

Individual drug particles or granules are coated with a slow-dissolving material.
The coated particles are compressed into tablets or placed in capsules.
The rate of drug release is controlled by the coating.
Varying the coating thickness and composition controls the release rate.

Reservoir Dissolution Controlled Formulation: Microencapsulation

Microencapsulation involves encapsulating solid, liquid, or gas materials into microparticles (1-1000 μm) with a core-shell structure.
The coating material can be natural or synthetic polymers, depending on the desired release characteristics.

Ion Exchange Resins (IER)

IERs are water-insoluble materials with charged groups on the resin chain.
Drug-charged resins are prepared using batch or column techniques.
Drug release is dependent on the ionic environment of the resin, making it less susceptible to pH or enzyme content.
IERs are not suitable for dermal or parenteral delivery.

Osmotic Controlled Delivery Systems

Push-Pull Osmotic System (PPOP): A multilayer system with a push layer that expands on contact with water, pushing the drug suspension through an orifice for controlled release.
Push-Stick Osmotic System (PSOP): A modified PPOP incorporating immediate and sustained drug release phases, suitable for poorly or highly water-soluble drugs.
Sandwiched Osmotic Tablet (SOTS): A tablet core with a push layer and two drug layers, coated with a semipermeable membrane.
Factors affecting drug release from osmotic pumps:
- Drug solubility: Highly or poorly water-soluble drugs are not ideal for osmotic delivery.
- CO2 generation: CO2 can cause swelling, leading to floating ability independent of pH and viscosity.

Gastroretentive Systems

Swellable Triple Layer System: Contains a core layer for controlled delivery, an outer layer for instant release, and a gas-generating layer for buoyancy.
Swellable Floating System: Contains hydrophilic colloids that form a gelatinous mass on the tablet surface, creating a water-impermeable barrier and buoyancy.

Marketed Gastroretentive Products

Madopar HBS: Levodopa and benserzide, HBS floating technology.
Valrease: Diazepam, HBS floating technology.
Liquid Gaviscon: Alginic acid and sodium bicarbonate, HBS floating technology.
Topalkan: Aluminum magnesium antacid, HBS floating technology.
Almagate: Antacid, HBS floating technology.
Glumetza: Metformin, size-increasing technology.
Proquin: Ciprofloxacin, size-increasing technology.

Ultra Long-Acting Oral Systems

Ultra-long-acting oral systems are important for treating chronic diseases (malaria, TB, HIV).
They aim to improve patient adherence and reduce logistical challenges in reaching rural populations.

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Description

Test your knowledge on enteric polymers, controlled release tablets, and sustained release tablets in this quiz. Explore key concepts surrounding drug delivery systems and their formulations. Perfect for students of pharmaceutical sciences or related fields.