Medicines are available in many forms for human consumption. Some of them are tablets, capsules, syrups, suspensions, emulsions, injections, lozenges, etc. These are taken based on the compatibility of patients. Tablets and syrups are the most common dosage forms. While tablets are suitable for the adult age group, children and the elderly are given liquid dosage forms such as syrup or suspension based on patient compatibility.
Syrup vs Suspension
The main difference between syrup and suspension is that syrup is a solution consisting of sugar that is readily dissolvable in other solvents, while the suspension is a biphasic liquid system containing insoluble solute particles in the liquid medium. The drug is completely soluble in syrup, while suspension consists of solid particles in the liquid phase.
A syrup is a liquid dosage form consisting of sugar and active pharmaceutical ingredient being completely soluble in it. Syrups are a clear monophasic liquid system consisting of a homogeneously mixed active ingredient. The sugar in the syrup helps to increase the palatability of the formulation.
Suspension is a biphasic liquid dosage form consisting of particles that are not completely soluble in the liquid media. The particle size for suspension is greater than 1 μm. The particles are in motion as such that they can settle down in a bottle and can be re-dispersed when shaken. The distribution of the drug or the active pharmaceutical ingredient should be uniform when the suspension is shaken.
Comparison Table Between Syrup and Suspension
| Parameters of Comparison | Syrup | Suspension |
| Definition | Monophasic liquid dosage form consisting of sugar and active pharmaceutical ingredient which is completely soluble in it. | Biphasic liquid dosage form consisting of particles that are not completely soluble in the liquid media. |
| Solvent system | Syrups can be aqueous-based or alcoholic syrups (called elixirs). | Suspensions are usually water-based systems. |
| Ideal for | Young children and the elderly are more compatible with syrup due to the sweet taste. | Ideal for diabetic patients who cannot administer syrup due to the presence of sugar. |
| Phases | A monophasic dosage form as the drug is completely dissolved. | A biphasic dosage form as the solid particles are not completely dissolved. |
| Types (based on usage) | Simple syrup, medicinal syrup, elixirs, flavoured syrup | Oral suspension, parenteral suspension, topically applied suspension(creams, lotions). |
What is Syrup?
A syrup is a solution consisting of sugar and an active pharmaceutical ingredient completely dissolved in it. This solute is completely dissolved in the solvent, and the resulting mixture is called a solution which is homogeneous in nature. This is the most convenient way of administering drugs in a liquid dosage form. The patients can easily administer it without any shaking requirement.
The solute particles are evenly distributed throughout the solvent system. This is one of the major advantages of this formulation.
Syrups can be aqueous-based systems or alcohol-based systems. The alcohol-based syrups are known as elixirs. Some syrups are incorporated with a high amount of sugar to increase palatability (in cases where the drug has an inappropriate taste). This helps in the administration of medication to children with ease.
Syrups can be of different types. The simple syrup is a sucrose solution having a concentration of 66.66% sucrose in water (e.g., Syrup USP). Flavoring syrups are syrups having specific flavored substances to give a different taste (e.g., Cherry Syrup). The syrups to which an active pharmaceutical ingredient has been added is known as a medicinal syrup (e.g., Guaiphenesin Syrup).