Hoja de repaso: Medicinal Product Knowledge

📋 Course Outline

1. Medicinal Product Definitions
2. Pharmaceutical Legal Categories
3. Drug Discovery Strategy
4. Molecular Modeling Applications
5. Me-too Drugs and NSAIDs
6. Clinical Drug Development
7. Clinical Trial Phases
8. Pharmacokinetic Pathway
9. Drug Quality Control
10. Dosage Forms and Administration
11. Prescription Rules

📖 1. Medicinal Product Definitions

🔑 Key Concepts & Definitions

• Active ingredient : the natural, chemical, or biotechnological substance responsible for the therapeutic action of a medicinal product
• Excipient : a natural or synthetic substance that facilitates administration, formulation, and preservation of the active ingredient and must be inert toward the organism and the active ingredient
• Medicinal product : Code de la Santé Publique — A medicinal product is a substance or composition presented as having curative or preventive properties, or capable of diagnosing, restoring, correcting, or modifying physiological functions through pharmacological, immunological, or metabolic action.

📝 Essential Points

📌 A medicinal product may be defined by presentation, by function, or by composition, including certain dietary products containing chemical or biological substances that confer therapeutic-dietetic properties.

💡 Memory Hook

Presentation identifies what a product appears to be, whereas function identifies what it does.

📖 2. Pharmaceutical Legal Categories

🔑 Key Concepts & Definitions

• Pharmaceutical specialty : a medicine prepared in advance by the pharmaceutical industry, presented in specific packaging, given a special name, and requiring marketing authorization for commercialization
• Magistral preparation : a medicine prepared according to a prescription for a specific patient because no suitable authorized pharmaceutical specialty is available
• Pharmacy for internal use : supplies hospitalized patients, manages and controls medicines, prepares and dispenses them, and may manage sterile medical devices and experimental medicines

★ Must-know

📌 A generic medicine has the same active-ingredient composition as the reference specialty and must demonstrate bioequivalence, whereas a me-too medicine has a modified but similar structure.

Further detail

• A pharmaceutical establishment manufactures and wholesales medicines under the responsibility of a pharmacist responsible for compliance with the Code de la Santé Publique.

💡 Memory Hook

Reference product → generic → magistral, officinal, hospital preparation

📖 3. Drug Discovery Strategy

🔑 Key Concepts & Definitions

• Hit : a first molecule with promising biological activity that is not sufficiently optimized to become a medicine
• Lead : an optimized molecule presenting an improved biological-activity profile and suitable for progression toward preclinical development

📝 Essential Points

• 🔄 Drug discovery proceeds through these stages:

  1. target selection
  2. bioactive-molecule design
  3. compound-library synthesis
  4. structure-activity analysis
  5. structural optimization of a hit

• Drug targets include:

  • receptors
  • enzymes
  • transport molecules
  • ion channels
  • idiosyncratic targets
  • nucleic acids

📌 In vitro experiments are performed outside a living organism, whereas in vivo experiments are performed in a living organism.

💡 Memory Hook

Target → design → library → screening → optimization

📖 4. Molecular Modeling Applications

🔑 Key Concepts & Definitions

• Molecular modeling : investigates molecular structures and properties using computational chemistry and graphical visualization to produce a plausible three-dimensional representation under defined conditions
• Pharmacophore : a spatial arrangement of chemical functions necessary for a molecule's biological activity

★ Must-know

• Homology modeling searches for a structurally known sequence analogue, aligns the sequences, builds a model by replacing different amino acids, then performs energy minimization and model validation.

Further detail

• UniProt is a database of protein or nucleic-acid sequences, whereas the Protein Data Bank is a database of three-dimensional structures.

• The seven pharmacophore functions are:

  • aromatic hydrophobic function
  • aliphatic hydrophobic function
  • positive charge
  • negative charge
  • ionizable group
  • hydrogen-bond donor
  • hydrogen-bond acceptor

💡 Memory Hook

Receptor-based modeling starts from the target, whereas receptor-free modeling starts from molecular structure.

📖 5. Me-too Drugs and NSAIDs

🔑 Key Concepts & Definitions

• Me-too drug : a new active pharmaceutical ingredient structurally close to an original medicine, acting through a similar mechanism but differing sufficiently in structure to be patentable

★ Must-know

• Salicylic acid, the lead of the arylcarboxylic-acid series, contains a benzene ring, a carboxylic-acid function, and a hydroxyl function.

Further detail

• The common international nonproprietary-name suffixes -olol and -azepam group beta-blockers and benzodiazepines, respectively.

• To develop a me-too, an industrial company monitors competitors' patents, synthesizes uncovered analogues, selects one using preclinical studies, files a patent, conducts clinical studies, requests marketing authorization, and markets the product.

• Acetylsalicylic acid, or aspirin, is obtained by adding acetic acid to the hydroxyl group of salicylic acid through an ester bond.

💡 Memory Hook

A generic is identical to the reference product, whereas a me-too is structurally similar but distinct.

📖 6. Clinical Drug Development

★ Must-know

• Drug research and development lasts approximately 10 years, costs more than one billion euros overall, and is protected by a patent lasting 20 years.

• 🔄 Drug development includes:

  1. in vitro research and development
  2. in vivo preclinical development
  3. clinical development in humans
  4. marketing authorization

Further detail

• Preclinical development costs approximately 10 to 20 million euros, whereas the early preclinical stage described in the course costs approximately 1.5 million euros and has 90% failures.

• After identification of a lead, galenic, pharmacokinetic, pharmacodynamic, and toxicological studies are performed to prepare the medicine and establish patient-safety rules.

💡 Memory Hook

Discovery → preclinical → clinical phases → marketing authorization

📖 7. Clinical Trial Phases

★ Must-know

• Clinical development progresses from phase I to phase IV, with progressively larger numbers of subjects, from fewer than 100 in phase I to several thousand in phase III.

• Phase I studies the maximum tolerated dose, pharmacokinetics, and pharmacodynamics when possible in fewer than 100 healthy volunteers.

• Phase II evaluates potential efficacy and toxicity, the dose-effect relationship, and the optimal dose in fewer than 500 volunteer patients.

• Phase III evaluates the benefit-risk ratio, defines the indication and special populations, and can support marketing authorization in fewer than 5000 ill patients.

Further detail

• Phase IV occurs after marketing and studies comparison with existing treatments, usefulness, pharmacoeconomics, tolerance, and marketing, only within the indication defined in phase III.

💡 Memory Hook

Phase I tolerability → Phase II dose → Phase III benefit-risk → Phase IV real-world use

📖 8. Pharmacokinetic Pathway

★ Must-know

📌 Pharmacokinetics describes what the organism does to the medicine through the dose-concentration relationship, whereas pharmacodynamics describes what the medicine does to the organism through the concentration-effect relationship.

• The ADME sequence comprises absorption, distribution, metabolism, and elimination.

📌 Passive diffusion follows a concentration gradient, uses no energy or transporter, and is not saturable, whereas facilitated diffusion uses saturable transporters and can involve competition between medicines.

• Distribution separates the active free fraction from the protein-bound reserve fraction, whose weak reversible binding can compete and is reduced during hypoalbuminemia.

• Drug metabolism mainly occurs in the liver and includes phase I functionalization by oxidation, reduction, or hydrolysis followed by phase II conjugation with endogenous polar molecules.

Further detail

• Active transport moves molecules against their concentration gradient through influx proteins such as OAT/OCT or efflux proteins such as P-glycoprotein and MRP.

💡 Memory Hook

ADME: Absorption, Distribution, Metabolism, Elimination.

📖 9. Drug Quality Control

🔑 Key Concepts & Definitions

• Good Manufacturing Practices : OMS — quality-assurance elements ensuring that products are manufactured and controlled uniformly according to standards appropriate to their use and specified in the marketing authorization

★ Must-know

• Medicine quality requires quality, safety, and efficacy, which are assessed through quantitative and qualitative analytical studies based on physicochemical methods.

• The World Health Organization acts internationally, the Council of Europe acts at the European level through the European Pharmacopoeia, and the ANSM applies the framework nationally in France.

📌 Analytical controls qualify what is present, quantify how much is present, identify substances, and detect impurities or related substances that should be absent or below defined limits.

Further detail

• European Pharmacopoeia monographs cover:
  • active ingredients
  • excipients
  • reagents
  • pharmaceutical forms
  • containers
  • analytical methods

💡 Memory Hook

Raw materials → formulation → packaging → finished-product control

📖 10. Dosage Forms and Administration

🔑 Key Concepts & Definitions

• Galenic form : the concrete pharmaceutical appearance of a medicine, such as a tablet, eye drop, gel, capsule, lotion, patch, or ointment

★ Must-know

• The main parenteral routes are:
  • intravenous
  • intramuscular
  • subcutaneous
  • intradermal

Further detail

• Galenic forms can be classified by physical appearance as solid, liquid, semisolid, or gaseous, or by administration route as oral, parenteral, or cutaneous.

• A syrup is an aqueous preparation with a sweet taste and viscous consistency, containing at least 45% m/m sucrose or another specified polyol or sweetener.

• An emulsion disperses liquid globules in another immiscible liquid, with either a lipophilic phase in a hydrophilic phase or a hydrophilic phase in a lipophilic phase.

• Gastro-resistant tablets resist gastric juice and release their active substances in intestinal juice.

💡 Memory Hook

Oral administration uses the digestive route, whereas parenteral administration crosses the skin.

📖 11. Prescription Rules

★ Must-know

• Prescribers include physicians and, within their scope of practice, midwives, dental surgeons, and physiotherapists for certain medical devices; since 2019, pharmacists can dispense and prescribe certain vaccines but generally do not prescribe medicines.

📌 Prescribing should follow the marketing authorization and the Summary of Product Characteristics, account for benefit-risk, and use explicit information adapted to the patient's pathology, history, allergies, previous treatments, and expectations.

• An ordonnance must include the date, prescriber identification, patient identification, medicine name, form, dose, route, duration, renewal instruction, and the prescriber's signature immediately below the last line.

• The four types of ordonnance are:

  • simple ordonnance
  • secured ordonnance
  • two-zone ordonnance
  • exceptional-medicine ordonnance

📌 A hospital-prescription medicine must be prescribed in a health establishment but may be dispensed in the community, whereas a hospital-initial-prescription medicine may be renewed by any prescriber after the initial hospital prescription.

Further detail

• For a medicine reserved for certain specialists, the initial prescription is restricted to specialist physicians, but subsequent renewal may be performed by any physician when only the initial prescription is restricted.

💡 Memory Hook

Patient → medicine → dose → route → duration → signature

📊 Synthesis Tables

Clinical Development Phases

Phase	Population	Main objective
I	Fewer than 100 healthy volunteers	Maximum tolerated dose, pharmacokinetics, and possible pharmacodynamics
II	Fewer than 500 volunteer patients	Efficacy, toxicity, dose-effect relationship, and optimal dose
III	Fewer than 5000 ill patients	Benefit-risk, indication, special populations, and marketing authorization
IV	Patients after marketing	Comparison, pharmacoeconomics, tolerance, and usefulness

Prescription Categories

Category	Initial prescriber	Renewal
PH	Hospital or clinic prescriber	Treatment may be dispensed in the community
PIH	Hospital or clinic prescriber	Any prescriber after the initial prescription
PRS	Certain specialist physicians	Any physician when only the initial prescription is restricted
Exceptional medicine	Qualified prescriber on CERFA form	Subject to the specific prescription requirements