L12 Turning a Drug into a Medicine -

Questions and Answers

What distinguishes a chemical property from a physical property in terms of substances?

A chemical property describes the potential for a substance to undergo a change based on its composition, while a physical property can be observed or measured without changing the substance's chemical identity.

Which physical property of diclofenac may influence its ability to dissolve in a solution?

The LogP (partition coefficient) of diclofenac, which indicates its lipid solubility, affects its dissolution in a solution.

How does density relate to the physical properties of a substance like diclofenac?

Density, a physical property, describes the mass per unit volume of diclofenac, affecting its formulation and stability.

What is an example of a chemical property of a substance and its significance?

Corrosion of metals is a chemical property, illustrating how some substances can react to form new compounds, such as metal oxides. Signup and view all the answers

What does a high partition coefficient (LogP) imply about a drug's physical properties?

A high LogP indicates that the drug is lipophilic, suggesting it partitions easily into membranes and may have better absorption properties. Signup and view all the answers

Define a property that could categorize a substance as 'Big' in terms of molecular mass.

A substance is categorized as 'Big' if it has a molecular mass greater than 500-1000 Da. Signup and view all the answers

What distinguishes a drug from a medicine in the context of pharmacology?

A drug is an active compound, while a medicine includes the drug along with other chemicals and devices necessary for its effective administration. Signup and view all the answers

At what stage is a drug considered to be developed into a medicine according to the provided content?

A drug is developed into a medicine during the phase between lead optimisation and preclinical development. Signup and view all the answers

What does TPP stand for and what role does it play in medicine design?

TPP stands for Target Product Profile, which sets the criteria and expectations for the medicine’s design. Signup and view all the answers

How do chemical and physical properties influence the design of a medicine?

Chemical and physical properties inform aspects of medicine design such as drug formulation, stability, and effective delivery routes. Signup and view all the answers

What are the two types of properties that must be considered in medicine development as mentioned in the content?

The two types of properties are physical properties and chemical properties. Signup and view all the answers

What does it mean for a formulation to either conserve or adapt the drug's behaviors in medicine design?

It means that a formulation must maintain the drug's original properties or alter them to optimize administration and effectiveness. Signup and view all the answers

Why is maintaining high quality of a medicine essential?

Maintaining high quality is essential to ensure the drug remains effective and safe for consumption throughout its shelf life. Signup and view all the answers

Can physical properties of a drug be observed without altering its composition? Provide an example.

Yes, physical properties can be observed without changing the composition; for example, the melting point of a substance. Signup and view all the answers

What is the absorption time difference among the lung, intestine, and skin when administering medicines?

Absorption occurs in minutes for the lung, hours for the intestine, and days for the skin. Signup and view all the answers

What regulatory measures ensure the quality of medicines in the UK?

Regulations are very strict, and even generics must undergo testing to ensure quality. Signup and view all the answers

Name three critical quality aspects to consider when evaluating drug quality.

Drug purity, excipient purity, and formulation quality. Signup and view all the answers

How does the target product profile influence medicine design?

It guides the design by specifying the desired characteristics and behaviors of the drug. Signup and view all the answers

Why is the manufacturing cost of transferring medicine characteristics significant?

It can cost around £2 million, reflecting the complexity and regulatory requirements of pharmaceutical manufacturing. Signup and view all the answers

What is meant by 'formulation quality' in the context of medicines?

Formulation quality includes aspects such as appearance, drug release, absorption, and pharmacokinetics (PK). Signup and view all the answers

How do intrinsic behaviors of a drug relate to its physical and chemical properties?

Intrinsic behaviors are determined by the drug's physical and chemical properties, influencing its effectiveness. Signup and view all the answers

In what way can a formulation adapt a drug's behaviors?

A formulation can conserve or alter a drug's behaviors to enhance its therapeutic effects. Signup and view all the answers

What does PKa indicate about a drug's properties?

PKa indicates the ionization constant of a drug, showing how dissolvable it is in a solution. Signup and view all the answers

How does the Log P value influence a drug's absorption?

Log P reflects the hydrophilicity or lipophilicity of a drug, which affects its permeability and absorption in biological membranes. Signup and view all the answers

What role does dissolution rate play in drug efficacy?

Dissolution rate affects how quickly a drug enters solution and is available for absorption, impacting its therapeutic effectiveness. Signup and view all the answers

How does molecular weight relate to drug behaviour?

Molecular weight can influence a drug's distribution and clearance rates in the body, as well as its ability to permeate cell membranes. Signup and view all the answers

What is the significance of a drug having low solubility?

Low solubility can restrict drug absorption and bioavailability, potentially reducing its therapeutic effect. Signup and view all the answers

Can you explain the relationship between chemical properties and functional characteristics?

Chemical properties, such as PKa and Log P, dictate functional characteristics like ionization and solubility, influencing drug behaviour. Signup and view all the answers

What factors must be considered in formulation design?

Formulation design must prioritize achieving appropriate drug delivery while conserving drug activity and stability. Signup and view all the answers

Why is good chemical stability important for medicines?

Good chemical stability ensures that the drug remains effective and safe over its shelf life, preventing degradation. Signup and view all the answers

How does pharmacokinetics impact drug failures?

Pharmacokinetics accounts for 40% of drug failures, and its changes can lead to formulation adjustments. Signup and view all the answers

What are the advantages of the buccal route of drug delivery?

The buccal route allows for sustained local delivery or rapid systemic absorption, such as through nitroglycerin for angina relief. Signup and view all the answers

What is the significance of the inhaled route in drug absorption?

The inhaled route offers a large absorption surface area, approximately 140 m2, making it attractive for systemic drug delivery. Signup and view all the answers

Describe the three regions of the nasal cavity involved in drug absorption.

The three regions are the vestibules, the respiratory region with turbinates, and the olfactory region. Signup and view all the answers

What is the primary barrier to drug permeation in the dermal route?

The primary barrier is the stratum corneum, the outermost layer of the skin. Signup and view all the answers

How can the route of delivery influence pharmacokinetics?

Different routes of delivery can alter absorption rates, bioavailability, and overall drug effectiveness. Signup and view all the answers

Why is the nasal cavity's surface area important for drug delivery?

The nasal cavity's surface area of 150 to 180 cm2 facilitates efficient drug absorption into the systemic circulation. Signup and view all the answers

What role does formulation play in pharmacokinetics?

Formulation can significantly change pharmacokinetics, affecting the release and absorption rates of drugs. Signup and view all the answers

Study Notes

Turning a Drug into a Medicine

A drug is an active compound, while a medicine includes additional chemicals and devices needed for effective delivery.
Medicine development occurs between lead optimization and preclinical development stages.
The Target Product Profile (TPP) sets design criteria for medicines and informs their development.

Properties of Medicines

The intrinsic behaviors of a drug include its chemical and physical properties.
Physical properties can be observed without altering the substance's composition (e.g., temperature, density).
Chemical properties reflect the potential of a substance to undergo changes due to its composition.

Key Chemical and Physical Properties

Physical Properties: Characteristics observable without changing the matter (e.g., size above 500-1000 Da).
Chemical Properties: Include potential reactions based on elemental composition, bonding, and structure.
LogP (partition coefficient) indicates lipid solubility; PKa (ionization constant) informs drug solubility.

Routes of Delivery

Formulation design focuses on appropriate delivery routes to preserve drug activity.
Pharmacokinetics (PK) accounts for 40% of drug failures, emphasizing the significance of formulation in this area.
Different routes of delivery (oral, buccal, inhaled, nasal, dermal) affect pharmacokinetics uniquely.

Oral Delivery Routes

Buccal Route: Sustained local delivery or rapid systemic absorption; involves hard tablets or rapidly disintegrating tablets.
Inhaled Route: High surface area (about 140 m²), beneficial for systemic drug absorption; structured like an 'upside-down tree'.

Nasal and Dermal Delivery

Nasal Route: Contains three regions (vestibules, respiratory, and olfactory) with a volume of 15-20 cm³ and a surface area of 150-180 cm².
Dermal Route: The stratum corneum serves as the main barrier to drug penetration, affecting absorption rate significantly.

Medicine Quality

Strict regulations ensure the quality of medicines; UK maintains high quality standards for generics.
Each type of medicine is characterized by distinct qualities and manufacturing processes, often involving significant costs (approximately £2 million).
Quality assessments focus on drug purity, excipient quality, formulation appearance, drug release, absorption, and pharmacokinetics.

Conclusion

Target Product Profile (TPP) is crucial for guiding medicine design.
Understanding the chemical and physical properties of drugs is essential for effective formulation and delivery strategies.

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Description

Explore the transformative journey of active compounds into effective medicines in this quiz. Delve into the properties, design, and quality control of medicines, as well as the various routes of delivery. This quiz is based on the lecture by Prof Stuart Jones from King's College London.