Concentrated Extracts (HTCX) in Drug Preparation

I. General Introduction

Concentrated extract preparation (HTCX) is a widely used method for producing various drug forms from herbal materials. This method relies on the principle of concentrating herbal extracts, eliminating most of the water and unnecessary substances, resulting in a concentrated preparation containing the primary active ingredients.

II. Drug Forms Prepared using HTCX

1. Extracts (Concentrated)

• Concept: Extracts are preparations made by concentrating and drying herbal extracts to a specific consistency – liquid, thick, or dry. Extracts contain high concentrations of the active ingredients present in the original herbal material, with most or all impurities like mucilage, gum, fat, and resin removed.
• Classification of Extracts:
  • Based on Origin:
    • Herbal Extracts: Prepared from plant parts like roots, leaves, flowers, fruits, etc.
    • Animal Extracts: Prepared from animal parts like horns, bones, skin, etc.
  • Based on Consistency:
    • Liquid Extract: A viscous liquid, typically 1 ml of liquid extract contains the same amount of active ingredients as 1 g of the original herb.
    • Thick Extract: A viscous substance containing approximately 15-20% water. It’s pliable and non-sticky, with a moisture content of 10-15% water.
    • Dry Extract: A dry, friable substance containing less than 5% water.
  • Based on Extraction Solvent:
    • Licorice Extract, Rhubarb Extract: (prepared using water)
    • Ephedra Extract, Belladonna Extract: (prepared using ethanol)
  • Based on Extraction Method:
    • Maceration: Often used for extract preparation, as the concentrated initial extract is separated, minimizing heat exposure to active ingredients.
    • Cold Maceration: Used for herbal materials without cells, using water as the solvent.
    • Hot Maceration: Decoction, infusion, maceration (used for herbal materials with cells, using water as the solvent).
• Characteristics of Extracts:
  • Active Ingredient Ratio: Usually higher than the active ingredient ratio in the original herb.
  • Active Ingredient Ratio in Liquid Extracts: May be equal to the active ingredient ratio in the original herb.
  • Applications: Extracts are rarely used directly. They are commonly used to formulate other drug forms, such as syrups, potions (liquid extracts), ointments, pills (thick extracts), tablets, and powders (dry extracts).

2. Tinctures

• Concept: Tinctures are preparations made by soaking herbal materials in alcohol or spirits. The soaking process extracts the active ingredients from the herbal material into the solvent.
• Advantages:
  • Longer shelf life compared to other drug forms due to the antimicrobial properties of alcohol/spirits.
  • The active ingredients in tinctures are easily absorbed by the body.
• Disadvantages:
  • Alcohol/spirits can irritate the gastric mucosa and may not be suitable for children or individuals with liver disease.

III. Techniques for Extract Preparation

• Four Main Stages:
  1. Extraction Preparation:
     • The herbal material is dried and ground to an appropriate fineness.
     • An appropriate solvent is chosen (water, alcohol, low-grade alcohol, alcohol-glycerin-water mixtures).
     • An appropriate extraction method is employed (cold maceration, hot maceration, maceration).
  2. Removing Impurities from the Extract:
     • Removing water-soluble impurities: gum, mucilage, pectin, starch, tannins using heat, 90° ethanol, lime milk, lead acetate, lead alkali, dialysis, electrodialysis, dialyzing.
     • Removing alcohol-soluble impurities: resin, fat using acidic water, solid paraffin, organic solvents (ether, chloroform).
  3. Concentration and Drying:
     • Concentration is performed at normal or reduced pressure to remove most of the water.
     • The concentrated extract is dried into a liquid or soft extract using a conventional oven or a cylindrical dryer.
  4. Quantifying the Active Ingredient Ratio, Finalizing the Preparation:
     • The active ingredient content in the extract is tested.
     • The active ingredient concentration is adjusted by mixing with a higher concentration extract, further concentration, dilution with a solvent, or excipients.
     • Additives (preservatives, flavoring agents) are added to the extract for a pleasant taste and better preservation.

IV. Notes

• Choosing the Right Solvent: Depending on the properties of the herbal material, the appropriate solvent should be chosen for optimal extraction of active ingredients.
• Controlling Temperature: Excessive temperatures can degrade active ingredients in herbal material, so appropriate temperatures should be used throughout the concentration and drying processes.
• Testing Active Ingredient Content: The active ingredient content in the extract should be tested after preparation to ensure product quality.
• Proper Storage: Store extracts in sealed containers, protected from light, in a dry, clean place to prevent deterioration.
• Safety Precautions: During extract preparation, adhere to occupational safety regulations and use appropriate personal protective equipment.

V. Conclusion

HTCX is an effective method for producing various drug forms from herbal materials. By applying appropriate preparation techniques and strictly controlling influencing factors, high-quality extracts can be produced, meeting the requirements for therapeutic efficacy and safety for users.