Introduction to Physical Pharmaceutics

Introduction to Physical Pharmaceutics

• Physical pharmaceutics studies how drug substance and dosage form physical properties affect behavior and performance.
• Relates material characteristics to therapeutic effects.
• Key areas include solubility, dissolution, stability, and drug delivery systems.
• Essential for designing safe and effective pharmaceutical products.

Drug Solubility and Dissolution

• Solubility is a drug's ability to dissolve in a solvent, crucial for absorption.
• Factors affecting solubility include drug nature (polarity, lipophilicity), solvent (polarity, pH), and temperature.
• Dissolution rate is the speed of drug dissolution in a solvent.
• Faster dissolution often means quicker absorption.
• Dissolution is vital for oral drug bioavailability.
• Particle size, surface area, and crystal form affect dissolution rate and extent.

Drug Stability

• Drug stability is the ability to maintain chemical and physical integrity over time.
• Factors impacting stability are moisture, temperature, light, oxygen, and reactive substances.
• Degradation reactions reduce activity, potentially leading to safety issues and toxicity.
• Stability studies determine drug shelf life.
• Formulations are crucial for maintaining stability and improving release rate/bioavailability.

Drug Delivery Systems

• Drug delivery systems improve drug efficacy and safety.
• Enhance bioavailability and minimize side effects.
• Types include solid (tablets, capsules), liquid (solutions, suspensions), and semisolid (creams, ointments).
• Advanced systems like nanoparticles, liposomes, microspheres provide targeted delivery and controlled release.
• Transdermal patches offer controlled delivery through the skin.
• Understanding drug release and absorption mechanisms enhances drug efficacy.
• Factors affecting formulations include drug-polymer interactions, drug stability, and release mechanisms.

Surfactants and their role in Pharmaceutical formulations

• Surfactants stabilize suspensions and emulsions.
• Dual hydrophobic/hydrophilic nature allows interaction with both drug and solvent.
• Reduce interfacial tension between phases, lowering energy required for mixing.
• Essential in emulsions, suspensions, and other pharmaceutical formulations.

Particle Size Reduction

• Particle size reduction increases surface area for dissolution and absorption.
• Leads to better bioavailability.
• Aids drug delivery through other routes, potentially needing less drug.
• Techniques include milling, micronization.

Polymorphism

• Polymorphism describes different crystalline forms of the same compound.
• Different polymorphs have varying physical properties (solubility, dissolution rate, melting point).
• Chosen polymorph significantly impacts a pharmaceutical product's performance.
• Understanding and controlling polymorphism is important for optimizing drug properties.

Other Important Concepts

• Osmotic pressure influences certain dosage forms.
• Compounding adjusts drug physical properties for customized delivery.
• Accurate dosage and mixing require pharmaceutical calculations.

Conclusion

• Physical pharmaceutics optimizes drug action while minimizing harm.
• Understanding physical properties is essential for safe, effective, and appropriately dosed pharmaceutical products.

This quiz explores the foundational concepts of physical pharmaceutics, focusing on how the physical properties of drug substances affect their performance. Key topics include drug solubility, dissolution processes, and their importance in pharmaceutical design. Understand the critical role these factors play in drug absorption and therapeutic efficacy.