Pharmaceutical Formulation 1: Syrup

1. Definition

Syrup is a liquid, sweet, viscous dosage form containing a high concentration of sugar (sucrose) ranging from 54-65%, equivalent to a specific gravity of 1.26-1.32. Syrups can be formulated as solutions or suspensions and are used for both single and multiple doses.

2. Classification

• Simple syrup: This type of syrup contains only sugar or sugar with flavoring agents and is used as a solvent or vehicle.

• Medicated syrup: This syrup is formulated for therapeutic purposes and contains active pharmaceutical ingredients.

3. Advantages of Syrups

• High sugar concentration: The high sugar content creates a hypertonic environment, inhibiting the growth of microorganisms and molds.

• Taste masking: The sweetness of the syrup helps to mask unpleasant tastes of the drug, improving patient acceptability.

• Easy to administer: Liquid dosage forms are easier to swallow, making them suitable for children and the elderly.

• Good stability: Syrups generally have good stability, minimizing the degradation of active ingredients.

• Nutritional value: The high sugar content in syrups provides energy to the body.

4. Disadvantages of Syrups

• Susceptibility to microbial contamination: The liquid nature of syrups makes them prone to contamination by microorganisms and molds. Proper storage is essential.

• Bulky, multi-dose: They can be cumbersome for accurate dose division, especially for pediatric patients.

• Active ingredient degradation: Some active ingredients may degrade in the humid environment of syrups.

• Unsuitable for patients with sugar restrictions: Due to the high sugar content, syrups are not suitable for patients with diabetes or those who have dietary restrictions.

5. Techniques for Preparing Simple Syrup

• Main component: Sucrose. Its solubility is 1:0.5, and its saturation concentration is 66.6%. Therefore, simple syrup has a sugar concentration close to saturation.

• Viscosity: Simple syrups exhibit high viscosity, which can pose challenges in mixing and filtration.

6. Stages of Simple Syrup Preparation

• Dissolving sugar: Dissolve sugar in purified water. Heat may be applied to accelerate dissolution.

• Measuring and adjusting sugar concentration: Use a hydrometer or boiling point method to determine the sugar concentration.

• Filtration: Remove any impurities from the syrup by filtering through cloth or filter paper.

• Bottling: Fill the syrup into bottles and store in a cool, dry place.

7. Dissolving Sugar in Simple Syrup

• At room temperature: Dissolving sugar at room temperature results in a specific gravity of 1.32 for the syrup.

• At boiling temperature: Dissolving sugar at boiling temperature and allowing it to cool results in a specific gravity of 1.32.

• Advantages of hot preparation:

• Faster dissolution and easier filtration.

• Reduced risk of microbial contamination.

• Disadvantages: The sugar may caramelize, giving the syrup a yellowish color.

• Note: The sugar dissolving temperature should not exceed 60°C to prevent caramelization.

8. Determining Sugar Concentration

• Weighing method: Weigh 1000 ml of simple syrup with a sugar concentration of 64%. It will weigh 1260 g at 105°C and 1314 g at 20°C.

• Boiling point method: Less commonly used due to the small difference in boiling points, making it difficult to read accurately. This can lead to large errors.

9. Adjusting Sugar Concentration

• Formula using Baume hydrometer: E= 0.033 SD

• E: Amount of water needed for dilution (ml).

• S: Mass of syrup (g).

• D: Baume degrees exceeding 35°.

• Formula using specific gravity: X= a.d2(d1-d)/d1.(d-d2).

• X: Amount of water to be added (ml).

• d1: Specific gravity of the syrup to be diluted.

• d: Desired specific gravity.

• d2: Specific gravity of the diluent (d2=1 for water).

• a: Amount of syrup to be diluted (ml).

10. Filtration and Clarification of Simple Syrup

• Filtration: Use cloth bags or filter paper with large pores to remove coarse impurities.

• Fine filtration:

• Filter paper: Remove fine impurities without introducing any foreign substances to the syrup.

• Clarification with albumin: Use high temperatures to coagulate albumin, which traps impurities. However, albumin may hydrolyze, leaving residue in the syrup.

• Decolorization: Use activated charcoal for decolorization.

• Note: Activated charcoal should not be used for medicated syrups, as it can adsorb active ingredients and reduce their effectiveness.

11. Preparing Medicated Syrups

• Method 1: Dissolve sugar into a solution of the drug.

• Method 2: Mix simple syrup with a drug solution.

12. Dissolving Sugar into the Drug

• Example: Iodo-tannic syrup.

• Advantages: Convenient, easy to perform, suitable for small-scale production.

• Disadvantages: Only yields a medicated syrup with a maximum sugar concentration of 64%.

13. Mixing Simple Syrup with the Drug

• Example: Chloral hydrate syrup.

• Advantages: Easy to perform, suitable for both large and small-scale production.

• Disadvantages: The resulting medicated syrup has a lower sugar concentration.

14. Preparing Medicated Syrups from Herbal Extracts

• Use concentrated extracts or tinctures of herbs, combined with simple syrup, to create a medicated syrup.

• Example: Gentian syrup 1/10: 1 part gentian extract + 9 parts simple syrup.

General Notes:

• Store syrups in a cool, dry place, protected from direct sunlight.

• Check the expiration date of the syrup before use.

• Use syrups as directed by a physician or pharmacist.

• Do not change the dosage or method of administration without consulting a healthcare professional.

• If any adverse effects occur, consult a physician or pharmacist immediately.

Additional Information:

• In addition to the above information, syrup preparation requires consideration of drug stability, compatibility of ingredients, viscosity, and the aesthetic appearance of the product.

• The choice of preparation method and excipients depends on the specific syrup and its intended use.

Conclusion:

Syrups are a popular dosage form offering advantages such as ease of administration, taste masking, and good stability. However, syrup preparation requires attention to several factors to ensure quality, safety, and efficacy.