922 Injections & Nanoparticles (Week 4)

What is the most important consideration in the formulation of injectable products?

Sterility is the most critical requirement for any injectable formulation.

Why must lyophilized powders be used for certain injectable drugs?

Lyophilized powders are used when a drug is unstable in liquid form and requires reconstitution before use.

When choosing a container for an injection, what are the three primary options mentioned?

The primary container options are vials, ampules, and cartridges.

Injectable delivery is preferred for emergency treatments like Epinephrine because it bypasses _____.

Absorption barriers

How do intramuscular (IM) injections achieve a very long duration of action?

They create a drug reservoir in the muscle that allows for slow drug release over weeks or months.

Why is insulin typically administered via injection rather than orally?

Insulin is a peptide drug that has low bioavailability and is rapidly degraded in the gastrointestinal tract.

What is the purpose of packaging dry sterile powders under nitrogen?

Nitrogen packaging protects drugs that are unstable in the presence of oxygen.

In injectable suspensions, the drug particles must be finely sized and remain easily _____.

Re-dispersible

What specific quality control limitation is placed on injectables regarding non-soluble material?

Injectables have strict limitations on foreign particulate matter.

Which injection route provides 100% systemic drug absorption?

Intravenous (IV) injection.

What is a significant clinical disadvantage of intravenous (IV) administration once the drug is injected?

The drug cannot be recalled once it has entered the systemic circulation.

How does tissue density in an intramuscular (IM) injection site affect drug delivery?

Denser muscle tissue results in slower drug diffusion.

Why are aqueous solutions absorbed slower via the intramuscular (IM) route than the intravenous (IV) route?

IM injections require the drug to diffuse from the muscle tissue into the bloodstream, whereas IV goes directly into circulation.

Which injection route involves administration into the tissue just beneath the skin?

Subcutaneous (SC) injection.

What is the primary diagnostic use for intradermal (ID) injections?

Intradermal injections are primarily used for allergy testing and diagnostic tests.

At what typical angle is an intradermal (ID) injection administered?

It is administered at a 10 to 15 degree angle.

Where is an intrathecal injection specifically delivered?

It is delivered into the intrathecal space surrounding the spinal cord.

What is the clinical goal of an intra-articular injection?

The goal is to provide local relief of inflammation or pain in a joint space, such as in arthritis.

Why are intra-arterial injections not routinely used?

Arteries are deep and difficult to access compared to veins.

Who is the only medical professional qualified to perform intra-ocular injections?

Only ophthalmologists are qualified to perform these injections.

In what extreme emergency setting is an intracardiac injection used?

It is used to restore the heartbeat during cardiac arrest.

What is the primary solvent used for most injectable solution formulations?

Water for Injection (WFI).

Define an injectable 'excipient'.

Excipients are inactive ingredients that support the drug's solubility, stability, or safety without having a therapeutic effect.

What is the typical concentration range for Benzyl alcohol when used as an antimicrobial preservative?

The typical concentration is 1% to 2%.

Name two antioxidants used in injectables to prevent oxidative degradation.

Ascorbic acid and Sodium metabisulfite are common antioxidants.

Which excipient category includes Citric acid and Phosphoric acid salts?

These are categorized as buffers used for pH maintenance.

What is the maximum usual concentration of Sodium chloride when used for tonicity adjustment?

The maximum usual concentration is 0.9%

What is the role of Edetate disodium (EDTA) in an injection?

EDTA acts as a chelating agent to enhance stability.

Why must oil-base solutions never be administered intravenously (IV)?

Administering oil-base solutions IV poses a high risk of pulmonary embolism.

In an injectable suspension, what is the relationship between dissolution and absorption?

The dissolution rate of the drug particles generally equals the absorption rate into the bloodstream.

What is the purpose of adding surfactants to an injectable suspension?

Surfactants improve the wetting of hydrophobic particles and prevent crystal growth.

Why are some drug systems packaged as dried powders for reconstitution?

They are used for drugs that are heat-labile or chemically unstable in aqueous environments over time.

What is the primary mechanism of sterilization for medical devices and packaging via ionizing radiation?

Ionizing radiation causes lethal DNA damage to microorganisms.

What is the standard pore size for filters used in sterile filtration of heat-labile drug solutions?

The standard pore size is 0.22 mu

What is a major limitation of sterile filtration compared to other sterilization methods?

Sterile filtration removes microorganisms but does not remove endotoxins (pyrogens).

How does a 'depot' injection differ from a standard solution injection?

A depot injection uses a matrix, like a biodegradable polymer, to release the drug slowly over time.

Which injection route bypasses the 'first-pass effect' of hepatic metabolism?

Injectable routes like IV, IM, and SC bypass the first-pass effect.

What is the particle size threshold for a formulation to be considered a 'solution'?

The particle size must be less than 1 nm

What is the particle size threshold for a formulation to be considered a 'suspension'?

The particle size is typically greater than 1000 nm

What type of excipient is used to maintain a stable pH between 6.0 and 8.2?

Phosphoric acid salts (Buffers).

Which antimicrobial preservative is typically used at a very low concentration of 0.002%?

Phenylmercuric nitrate and acetate.

Why are 'in situ forming gels' advantageous for long-term drug delivery?

They release the drug slowly as the depot matrix degrades, providing sustained therapeutic levels.

What must the labeling of a lyophilized powder specifically state for clinical use?

The labeling must specify the exact reconstitution and dilution instructions.

How does blood perfusion at the site of an intramuscular (IM) injection influence absorption?

Better blood perfusion at the site leads to faster drug absorption.

What is the primary risk associated with the intra-ocular route of injection?

There is a significant risk of retinal damage.

In injectable manufacturing, 'terminal sterilization' refers to sterilizing the product in its _____.

Final container

Which carbohydrate excipient is used both for tonicity adjustment and to stabilize biological actives during freezing?

Sucrose (or Trehalose).

What happens to the 'cake' of a lyophilized product if it is processed above its eutectic temperature?

The cake collapses, ruining the physical structure of the product.

What is the function of methylparaben and propylparaben in an injectable formulation?

They serve as antimicrobial preservatives.

Which injection route is described as being administered at a $90^{\circ}$ angle?

The intramuscular (IM) injection.

Why might a buffer like phosphate be problematic during the freezing phase of lyophilization?

Phosphate systems can undergo a pH shift during freezing, potentially destabilizing the drug.

What does the term 'pyrogen-free' mean in the context of injectable quality control?

It means the formulation is free of fever-inducing bacterial endotoxins.

Which route is preferred when a rapid initiation of antibiotic therapy is required in a hospital setting?

The intravenous (IV) route.

How does the viscosity of an oil-base vehicle affect the release of a drug compared to an aqueous vehicle?

Oil-base vehicles generally have higher viscosity and different absorption characteristics, leading to more prolonged release.

What is the primary site of administration for allergy testing?

The forearm is the common site for these intradermal injections.

Identify the tonicity agent often used up to a concentration of $5\%$.

Mannitol.

Injectable solutions must be 'particle-free,' meaning they must be clear and _____.

Homogeneous

Which route is specifically used for anesthetic administration during childbirth?

The intrathecal route.

What term describes the process where a liquid drug formulation is turned into a dry powder by freezing and removing water under vacuum?

Lyophilization.

When a drug has poor oral absorption due to first-pass metabolism, which route is often chosen as an alternative?

Injectable administration is chosen.

Why is the intravenous (IV) route associated with an increased chance of adverse reactions compared to oral routes?

The drug reaches systemic circulation immediately and at higher peak concentrations.

In subcutaneous injections, what are the three steps the drug must undergo if it is a suspension?

The steps are particle dissolution, followed by diffusion, and finally absorption.

What does 'WFI' stand for in pharmaceutical compounding?

Water for Injection.

What is the primary reason for using a co-solvent system in an injection?

Co-solvent systems are used as solubility enhancers for drugs that are poorly soluble in water.

Which sterilization method is best suited for medical devices but may degrade drug molecules?

Ionizing radiation.

What are injectable formulations?

Injectable formulations are designed for administration directly into the body, supplied as sterile liquids or lyophilized powders requiring reconstitution.

What is the most important consideration for injectable formulations?

Sterility is the most important consideration.

When are injectable formulations preferred over other routes?

When other routes are insufficient, ineffective, or unsafe, or when a rapid drug effect is needed.

What is the advantage of IM injections?

IM injections provide a drug reservoir in muscle, allowing for slow drug release and consistent therapeutic effects over weeks to months.

What are some situations where injectable formulations are used?

In emergency treatments, rapid initiation of antibiotic therapy, fast relief of acute pain, or when oral dosing is impossible.

What are the key requirements for injection preparation?

High-level quality control, sterility, and limitations on foreign particulate matter.

What are the routes of injection?

Intravenous (IV), Intramuscular (IM), Subcutaneous (SC), Intradermal (ID), Intrathecal, Intraspinal, Intra-articular, Intra-arterial, Intra-ocular, and Intracardiac.

What is a key characteristic of intravenous (IV) injections?

IV injections provide rapid effect and complete systemic drug absorption, but cannot be recalled.

What are the risks associated with IV injections?

Increased chance for adverse reactions, possible anaphylaxis, and contamination at the injection site.

What is the absorption characteristic of subcutaneous (SC) injections?

SC injections are slower than IV or IM and require multiple steps for absorption.

What is the purpose of intradermal (ID) injections?

ID injections are used for diagnostic tests and allergy testing.

What is the risk associated with intrathecal injections?

Intrathecal injections carry a risk of complications and are used for anesthetic administration or targeted pain control.

What is a key consideration for intra-articular injections?

They must be injected within the joint capsule and are often painful, requiring local anesthetic.

What are solutions in injectable formulations?

Solutions are clear, homogeneous liquids where the drug is fully dissolved in a solvent, typically water for injection.

What role do excipients play in injectable formulations?

Excipients are inactive ingredients that support the drug, improve solubility, maintain pH, ensure isotonicity, and enhance stability.

What are the characteristics of oil-based solutions?

Oil-based solutions are used when drugs are not water-soluble and provide a prolonged release profile, typically for IM injections.

What are suspensions in injectable formulations?

Suspensions are liquid dosage forms containing insoluble drug particles dispersed in a vehicle, used for extended-release effects.

What is the first step in the absorption of suspensions?

The vehicle spreads slightly within the tissue.

What are some challenges in injection formulation?

Challenges include maintaining sterility, being free of foreign particulates, and ensuring chemical and physical stability.

What is the significance of pH in injectable formulations?

pH is crucial for the safety and stability of injectable products.

What is the impact of first-pass metabolism on injectable formulations?

Injectable formulations bypass first-pass metabolism, enhancing drug bioavailability.

What is the purpose of using co-solvent systems in injections?

Co-solvent systems are used to enhance the solubility of poorly soluble drugs.

What is the role of quality control (QC) in injection preparation?

QC ensures that injections meet safety standards, including limits on foreign particulate matter and pyrogen control.

What are the potential complications of intracardiac injections?

Intracardiac injections are rare and used in emergencies to restore heartbeat during cardiac arrest.

What is the absorption characteristic of IM injections?

IM injections are absorbed slower than IV injections and can vary based on muscle group and blood flow.

What is the significance of using sterile powders in injections?

Sterile powders can be packaged under nitrogen to maintain stability and prevent degradation.

What are excipients?

Inactive formulation ingredients that support the drug, improve solubility, maintain pH, ensure isotonicity, enhance stability, and prevent microbial growth.

What type of solutions are used when a drug is not water-soluble?

Oil-base solutions, typically used for intramuscular (IM) injections for a prolonged release profile.

Why should oil-base solutions never be used for intravenous (IV) injections?

They pose a risk of pulmonary embolism.

What are suspensions in the context of injectable formulations?

Liquid dosage forms containing insoluble drug particles dispersed in a vehicle, often used for extended-release effects.

How do suspensions absorb into the bloodstream?

The vehicle spreads within tissue, tissue fluids wet suspended particles, the drug dissolves, and then it is absorbed.

What are key excipients in suspensions?

Suspending agents, surfactants, antioxidants, and buffers.

What is the significance of syringeability in suspensions?

It refers to the ability of the suspension to pass through a needle size (18-21 gauge) without difficulty.

What are emulsions?

Mixtures of two or more liquids that do not mix, often used to help solubilize drugs.

What are the two main types of emulsions?

Oil-in-water (O/W) and water-in-oil (W/O).