INTRODUCTION TO HERBAL FORMULATIONS: A TEACHER’S COMPREHENSIVE GUIDE
Welcome, future pharmacists and herbal formulation scientists!
Herbal formulations are dosage forms that consist of one or more herbs or processed herbs in specified quantities to provide specific nutritional and cosmetic benefits meant to be utilised for diagnosing, treating, mitigating diseases of human beings or animals, and for altering the structure or physiology of humans or animals.
As a pharmacognosy educator with years of experience teaching herbal formulations, I have observed that students often find the diversity of herbal dosage forms challenging. Let me tell you: Herbal formulations bridge traditional wisdom with modern pharmaceutical technology.
In this comprehensive guide, I will walk you through the classification, preparation, and evaluation of herbal formulations—including conventional/modern dosage forms (syrups, tablets, creams, mixtures), novel dosage forms (phytosomes, liposomes, niosomes, transferosomes, ethosomes), and the challenges in herbal formulation. By the end of this article, you will have a thorough understanding of these essential pharmaceutical preparations. Let us begin!
Dpharmguru’s exam insights:
Herbal formulations are frequently tested in pharmacognosy exams. Remember: Herbal formulations include syrups, tablets, tinctures, extracts, essential oils, and expressed juices. Novel dosage forms include phytosomes, liposomes, niosomes, transferosomes, and ethosomes. Key evaluation parameters for syrups include pH, microbial limits, and alcohol content. Tablets are evaluated for disintegration, hardness, friability, and moisture content. These are classic exam questions!
10.1. CLASSIFICATION OF HERBAL FORMULATIONS
Herbal formulations can be broadly classified into the following three categories:
- Modern/Conventional Herbal Dosage Forms: Tablets, syrups, solutions, capsules, and suppositories—user-friendly, convenient, with good absorption characteristics
- Novel Dosage Forms: Transdermal patches and nanosuspensions—overcome limitations of traditional forms
- Traditional Dosage Forms: Originated from Ayurveda, Unani, and Homeopathy (e.g., tablets, tinctures, powders, pellets, semi-liquid)
10.2. CONVENTIONAL/MODERN HERBAL DOSAGE FORMS
Conventional herbal dosage forms are herbal medications produced and delivered in accordance with standard techniques that are widely recognised and used in both traditional and modern healthcare practices.
10.2.1. Herbal Syrup
Herbal syrups are composed of equal amounts of herbal extracts and a known concentration of honey or sugar. It also contains various flavours, like orange, raspberry, or mentha added to mask bitterness and enhance formulation palatability.
10.2.1.1. Preparation of Herbal Syrup
- Raspberry Syrup: Made from the juice of ripe raspberries—popular among children
- Cherry Syrup: Obtained from the juice of ripe fruits—used in antibiotics, cough preparations, and sulpha-antibiotics
- Sarsaparilla Syrup: Suitable vehicle for iodide—considered as an inert vehicle by many pharmacists
- Glycyrrhiza Syrup: Effective masking agent for bitter substances, but not for sour acidic medicines
- Asava and Aristha: Ayurvedic preparations—e.g., Vasakasava, Ashokaristha
10.2.1.2. Evaluation Parameters for Herbal Syrup
- Material and mass uniformity
- pH determination
- Microbial limitations
- Antimicrobial preservative ingredients
- Antioxidant preservative ingredients
- Extractable from the container/closure system
- Content of alcohol
10.2.2. Herbal Tablet
Herbal tablets are solid dosage forms of powdered herbs, herbal extracts, or their ingredients that are prepared through moulding or compression.
10.2.2.1. Preparation of Herbal Tablet
- Weighing the Ingredients: Crude drugs ground to fine powder and passed through 100 mesh sieve
- Mixing: Consistently mixing of drugs and excipients to form a homogeneous mass
- Granulation:
- Wet Granulation Method: Most common method—mixing with granulating agents, passing through sieve No. 8 or 10, drying at 60°C, passing through sieve No. 20
- Dry Granulation: Crystalline or granular drugs passed through sieve No. 20
- Compression of Granules into Tablets: Using single-punch, multi-punch, and rotary tableting machines
10.2.2.2. Evaluation Parameters for Herbal Tablet
- Disintegration/Dissolution
- Hardness and friability
- Content and mass uniformity (dosage unit)
- Moisture content
- Microbial limitations
10.2.3. Herbal Cream
Herbal creams are viscous, semisolid preparations that can be oil-in-water type (aqueous) creams or water-in-oil type (oily) creams.
10.2.3.1. Preparation of Herbal Cream
- Preparation of the Oil Phase: Flake or powder materials dry mixed, dispersed in mineral oil or silicone oil, heated
- Hydration of Aqueous Phase Ingredients: Emulsifier, thickener, and stabiliser mixed with water, heated
- Forming the Emulsion: Both phases vigorously mixed
- Dispersion of the Active Ingredient: Active ingredient disseminated well to maximise yield and product performance
10.2.3.2. Evaluation Parameters for Herbal Cream
- pH of cream
- Viscosity
- Rheological behaviour of cream
- Determination of the type of emulsion
- Dilution test
- Dye solubility test
10.2.4. Herbal Mixture
Herbal mixtures are made from two or more ingredients which are formulated into tablets, capsules, ointments, creams, etc.
10.2.4.1. Preparation of Herbal Mixture
- Bhasmas: Calcined substances used in the preparation of metals, minerals, and animal products (e.g., gold ash)
- Churna: Fine powder made from specific medicines or combinations of drugs—examples include Triphala Churna, Trikatu Churna, Drekshaadi Churna, Sudarshan Churna
10.2.4.2. Evaluation Parameters for Herbal Mixture
- Colour
- Odour
- Appearance
- Clarity
- Viscosity
- Moisture content
- pH
- Disintegration time
- Friability
- Hardness
10.3. NOVEL DOSAGE FORMS
Novel drug delivery systems address the limitations of traditional drug delivery systems. If novel drug delivery technology is applied in herbal medicine, it increases the efficacy and reduces the side effects of various herbal compounds and herbs.
10.3.1. Phytosomes
Phytosome is a novel technology that emerged in 1989. The term phyto means plant/herb and some means cell-like structure. Phytosome is a technology used as controlled and sustained release delivery system that consists of phospholipid complex system of herbal extract or phytoconstituents in nano size range [<100nm] of particles.
Phytosomes are most suitable for drugs having poor aqueous solubility and strong tendency to self-aggregate.
10.3.2. Liposomes
Liposomes are bilayer vesicular carrier systems of phospholipids or cholesterol. Their size ranges from 25-2.5nm. Liposomes are advantageous due to their ability to encapsulate various materials and their structural versatility. They can encapsulate drugs having varying solubility or lipophilicity.
10.3.3. Niosomes
Niosomes are microscopic lamellar structures formed by admixture of a non-ionic surfactant, cholesterol, and a charge-inducing agent with subsequent hydration in aqueous media. They are made up of both hydrophobic and hydrophilic moieties, and thus can accommodate drug molecules with a wide range of solubility.
10.3.4. Transferosomes
The term transferosome means carrying body—derived from Latin transferre (to carry across) and Greek soma (body). Transferosomes are artificial vesicles resembling the natural cell vesicle, thus are suitable for targeted and controlled drug delivery.
Transferosomes are vesicular systems made up of phospholipids as the main ingredient with 10-25% surfactant (such as sodium cholate) and 3-10% ethanol. The surfactants work as edge activators and impart ultradeformability to transferosomes.
10.3.5. Ethosomes
Ethosomes are slightly modified versions of well-established drug-carrier liposomes. They are soft lipid vesicles made up of phospholipids, alcohol (ethanol and isopropyl alcohol in relatively high concentration), and water. Their size range may vary from tens of nanometers (nm) to microns (μ). Ethosomes rapidly permeate through the skin layers and possess higher transdermal flux.
10.4. CHALLENGES IN HERBAL FORMULATION
- Standardisation: Maintaining constant concentrations of active components across batches—plant sources and processing techniques vary
- Quality Control: Tracking potency, identity, and purity—avoiding contamination and guaranteeing product performance and safety
- Bioavailability: Improving inadequate metabolism and absorption to maximise the potency of herbal ingredients
- Safety Concerns: Reducing the possibility of harmful substances, pollutants, and drug interactions
- Regulatory Compliance: Managing various legal requirements for labeling, claims substantiation, and manufacturing
- Stability: Preserving the integrity and shelf life of a product—averting deterioration due to moisture and oxidation
- Cultural and Ethical Considerations: Considering sustainability, ethical sourcing, and cultural preferences
Dpharmguru’s exam insights:
Novel dosage forms and challenges in herbal formulations are frequently tested. Remember: Phytosomes (1989) are phospholipid complexes for controlled release. Liposomes are bilayer vesicular carriers (25-2.5nm). Niosomes use non-ionic surfactants. Transferosomes have edge activators for ultradeformability. Ethosomes contain alcohol for higher transdermal flux. Key challenges include standardisation, quality control, bioavailability, safety, and regulatory compliance. These are classic exam questions!
COMPARISON: NOVEL DOSAGE FORMS
| Type | Composition | Key Feature | Size |
|---|---|---|---|
| Phytosomes | Phospholipid + herbal extract | Controlled/sustained release | <100 nm |
| Liposomes | Phospholipids/Cholesterol | Bilayer vesicular carrier | 25-2.5 nm |
| Niosomes | Non-ionic surfactant + Cholesterol | Hydrophobic + Hydrophilic moieties | Microscopic |
| Transferosomes | Phospholipids + Surfactant + Ethanol | Ultradeformable | Vesicular |
| Ethosomes | Phospholipids + Alcohol + Water | Higher transdermal flux | nm to μ |
COMPARISON: EVALUATION PARAMETERS
| Dosage Form | Key Evaluation Parameters |
|---|---|
| Herbal Syrup | pH, Microbial limits, Alcohol content, Preservative ingredients |
| Herbal Tablet | Disintegration, Hardness, Friability, Moisture content |
| Herbal Cream | pH, Viscosity, Emulsion type, Rheological behaviour |
| Herbal Mixture | Colour, Odour, pH, Disintegration time, Hardness |
FREQUENTLY ASKED QUESTIONS (FAQs)
1. What are herbal formulations?
Herbal formulations are dosage forms that consist of one or more herbs or processed herbs in specified quantities to provide specific nutritional and cosmetic benefits for diagnosing, treating, or mitigating diseases.
2. What are the three categories of herbal formulations?
Herbal formulations are broadly classified into modern/conventional herbal dosage forms (tablets, syrups, capsules), novel dosage forms (phytosomes, liposomes, niosomes), and traditional dosage forms (tinctures, powders, pellets).
3. What is a phytosome?
A phytosome is a novel technology that emerged in 1989—a phospholipid complex system of herbal extract or phytoconstituents in nano size range (<100nm) used for controlled and sustained release delivery.
4. What is the difference between liposomes and niosomes?
Liposomes are bilayer vesicular carriers made of phospholipids or cholesterol. Niosomes are microscopic lamellar structures formed by admixture of non-ionic surfactant, cholesterol, and a charge-inducing agent.
5. What are the challenges in herbal formulation?
The key challenges include standardisation, quality control, bioavailability, safety concerns, regulatory compliance, stability, and cultural/ethical considerations.
6. What is the role of surfactants in transferosomes?
Surfactants (10-25%) in transferosomes work as edge activators and impart ultradeformability, helping them to squeeze through the pores in the stratum corneum.
SUMMARY
Herbal formulations represent the convergence of traditional wisdom and modern pharmaceutical technology. This guide covered:
- Classification: Modern/conventional, novel, and traditional dosage forms
- Conventional Dosage Forms: Herbal syrups (evaluation: pH, microbial limits, alcohol content), herbal tablets (evaluation: disintegration, hardness, friability), herbal creams (evaluation: pH, viscosity, emulsion type), herbal mixtures (evaluation: colour, odour, pH, disintegration time)
- Novel Dosage Forms: Phytosomes (1989, <100nm), Liposomes (25-2.5nm), Niosomes (non-ionic surfactant), Transferosomes (ultradeformable), Ethosomes (higher transdermal flux)
- Challenges: Standardisation, quality control, bioavailability, safety, regulatory compliance, stability, cultural/ethical considerations
As I always tell my students: “Herbal formulations are the future of natural medicine—combining ancient knowledge with modern technology to deliver safe, effective, and patient-friendly treatments.”
REFERENCES AND FURTHER READING
- Pharmacy Council of India (PCI). (2022). Pharmacognosy Syllabus. New Delhi: PCI.
- Kokate, C. K., Purohit, A. P., & Gokhale, S. B. (2020). Pharmacognosy (50th ed.). Nirali Prakashan.
- Trease, G. E., & Evans, W. C. (2019). Trease and Evans’ Pharmacognosy (16th ed.). Elsevier.
- World Health Organization (WHO). (2022). Guidelines on Quality Control of Herbal Medicines. Retrieved from https://www.who.int.
- Sharma, P. V. (2019). Charaka Samhita (English translation). Chowkhamba Orientalia.
Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare professionals for medical concerns. Herbal formulations should be used under proper guidance.
written by:
Dr. N. Sujith Kumar
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