BAHAN AJAR FARMASI. SEDIAAN LARUTAN #PART1

Summary

This lesson covers the topic of pharmaceutical solutions, focusing on the properties of solutes and solvents. It explores the different types of solvents such as water, alcohol, glycerin, and ether, and how they dissolve various solutes like salts, camphor, and menthol. The video discusses factors influencing solubility, including the nature of solute and solvent, cosolvency, temperature, and the salting-in and salting-out phenomena. It also explains how particle size, temperature, and agitation affect the rate of dissolution. By the end, viewers will gain a comprehensive understanding of the factors that determine the solubility of substances in different solvents.

Takeaways

• 😀 A solution is a liquid preparation containing one or more dissolved substances, with solute being the dissolved substance and solvent being the dissolving substance.
• 😀 Common solvents include water, alcohol (spiritus), glycerin, ether, oils, and liquid paraffin, with each capable of dissolving specific solutes.
• 😀 Polar solutes dissolve in polar solvents, while non-polar solutes dissolve in non-polar solvents, highlighting the importance of matching solvent and solute properties for effective dissolution.
• 😀 Cosolvency occurs when the solubility of a substance increases by adding another solvent, like combining glycerin and water to dissolve substances like luminal.
• 😀 Solubility varies with the ease of dissolution; some substances dissolve quickly, requiring less solvent, while others require more solvent due to their difficulty in dissolving.
• 😀 Temperature influences solubility: endothermic dissolution requires heat, while exothermic dissolution releases heat, affecting how substances dissolve in different conditions.
• 😀 Salting out occurs when adding a more soluble substance, like NaCl, reduces the solubility of a less soluble substance, such as essential oils, leading to precipitation.
• 😀 Salting in is the reverse process, where adding certain substances (e.g., nicotinamide) increases the solubility of another solute (e.g., riboflavin) in a solvent.
• 😀 The formation of complexes can enhance solubility; for example, iodine becomes soluble in water when combined with potassium iodide to form a complex.
• 😀 The rate of dissolution is affected by factors like particle size, temperature, and agitation. Smaller particles, higher temperatures, and stirring all speed up the dissolution process.

Q & A

What is a solution in the context of pharmaceutical preparations?

A solution is a liquid preparation that contains one or more dissolved chemical substances, called solutes. These solutes are dissolved in a solvent, creating a homogeneous mixture.

How do solutions differ from emulsions and suspensions?

Solutions are homogeneous mixtures where the solute is fully dissolved in the solvent, while emulsions and suspensions are heterogeneous mixtures where the solute is not fully dissolved, and separation can occur.

What is the difference between a solute and a solvent?

A solute is the substance that dissolves in a solvent to form a solution. The solvent is the medium that dissolves the solute, typically in a liquid state.

Can you list some common solvents used in pharmaceutical preparations?

Common solvents include water, spiritus (alcohol), glycerin, ether, oils, and paraffin liquidum. These solvents are chosen based on their ability to dissolve specific solutes.

What factors influence the solubility of substances in solvents?

Factors include the nature of the solute and solvent (polar or non-polar), temperature, cosolvency, salting out and salting in effects, and the formation of complexes between solutes and solvents.

What is cosolvency, and how does it affect solubility?

Cosolvency is the increase in solubility of a solute when a secondary solvent is added to the primary solvent. This modification can enable substances that would not normally dissolve to become soluble.

How does temperature affect solubility?

Temperature can either increase or decrease solubility depending on the nature of the process. For endothermic processes, solubility increases with higher temperatures, while for exothermic processes, solubility decreases as temperature rises.

What is the salting out effect in solubility?

Salting out occurs when a solute's solubility is decreased due to the addition of a substance that has a higher solubility. An example is adding sodium chloride (NaCl) to a solution containing essential oils, which causes the oils to precipitate.

What is salting in, and how does it influence solubility?

Salting in refers to the process where the addition of certain substances, like nicotinamide, increases the solubility of another substance, such as riboflavin, in a solvent.

How do particle size, temperature, and stirring affect the rate of dissolution?

Smaller particle sizes increase the surface area, which speeds up dissolution. Higher temperatures generally speed up dissolution, and stirring helps the solute dissolve faster by moving the solvent around the solute.