Herbal Drug Evaluation: WHO, ICH, and GMP Standards

Posted on Jun 23, 2026 in Other university degrees and diplomas

Evaluation of Drugs

WHO Guidelines for Evaluation of Drugs

The World Health Organization (WHO) has provided specific guidelines to ensure that herbal and crude drugs are safe, effective, and of good quality.

Because herbal drugs come from natural sources, their quality may vary due to climate, soil, collection methods, processing, and storage. Therefore, WHO guidelines help in the standardization, quality control, safety, and efficacy evaluation of crude drugs.

Objectives of WHO Guidelines

To ensure the identity, purity, and strength of herbal drugs.
To evaluate safety and efficacy.
To promote the rational use of herbal medicines.
To support global acceptance of herbal drugs.
To reduce risks of adulteration and contamination.

Main Guidelines for Evaluation

According to the WHO, the evaluation of herbal drugs is broadly divided into four main aspects:

Assessment of Quality
Assessment of Safety
Assessment of Efficacy
Intended Use

1. Assessment of Quality

Quality assessment ensures that the crude drug is pure, genuine, and of a high standard. It involves:

Pharmaceutical Assessment
Crude Plant Material
Plant Preparation
Finished Product
Stability

A. Pharmaceutical Assessment

This covers all important quality aspects of herbal drugs. Pharmacopoeial standards should be followed whenever available. If no monograph is available, a proper monograph should be prepared. All manufacturing steps should follow Good Manufacturing Practices (GMP).

B. Crude Plant Material

The correct botanical name of the plant should be mentioned to avoid adulteration.
The correct part of the plant used should be clearly specified.
The condition of the drug should be mentioned (whether fresh or dried).
Important chemical constituents should be identified if possible.
Limits for foreign matter like dust, insects, and microbial contamination should be fixed.
Each batch should have a voucher specimen authenticated by a botanist, stored for future reference.
A lot number should be assigned to each batch for identification.

C. Plant Preparations

Methods of preparation, such as powdering or extraction, should be clearly described.
Identification tests should be carried out to confirm quality.
If the active compound is unknown, chromatographic fingerprinting should be used.
Consistency in quality should be maintained for every batch.

D. Finished Product

The complete manufacturing formula, including excipients, should be mentioned.
Quality specifications of the finished product should be defined.
Identification of plant material in the final product should be carried out.
Uniform quality should be maintained across all batches.

E. Stability

Physical and chemical stability of the product should be tested.
Proper storage conditions should be defined.
Shelf life and expiry dates should be fixed.

2. Assessment of Safety

Safety evaluation ensures that herbal drugs do not cause harmful effects. It involves Toxicological Studies and Safety Based on Experience.

A. Toxicological Studies

Toxicity studies should be carried out whenever required to help identify the harmful effects of the drug.

B. Safety Based on Experience

A long history of traditional use can support safety.
Known toxic effects and risks should be properly documented.
Safety should be evaluated in relation to the dose.
The possibility of misuse, abuse, or dependence should be checked.
Side effects should be recorded and monitored.

ICH Guidelines for Herbal Drug Evaluation

The International Council for Harmonisation (ICH) provides guidelines to ensure herbal drugs are safe, effective, and of consistent quality. Although ICH guidelines were mainly developed for synthetic drugs, many principles are applied to herbal and traditional medicines.

Basic Guidelines of ICH

ICH guidelines are categorized into:

Quality Guidelines
Safety Guidelines
Efficacy Guidelines
Multidisciplinary Guidelines

1. Quality Guidelines

ICH quality guidelines focus on maintaining the consistent quality of herbal drugs through:

Proper identification of raw herbal material.
Control of impurities and contaminants.
Stability testing to ensure shelf life.
Use of validated analytical methods.
Good Manufacturing Practices (GMP) during processing.

2. Safety Guidelines

Safety guidelines evaluate the toxic potential of herbal drugs via:

Toxicity and genotoxicity studies.
Carcinogenicity testing (if required).
Reproductive and long-term toxicity studies.

3. Efficacy Guidelines

Efficacy guidelines ensure that herbal drugs produce the claimed therapeutic effect through:

Clinical trials in human subjects.
Dose-response studies.
Good Clinical Practices (GCP).
Pharmacovigilance (monitoring adverse effects).

4. Multidisciplinary Guidelines

These cover common technical aspects used in drug evaluation:

Common Technical Document (CTD).
Electronic Data Submission (eCTD).
Standard terminology and documentation.

Stability Testing of Herbal Drugs

Stability testing determines how the quality, safety, and efficacy of a herbal drug change over time under the influence of temperature, humidity, light, and storage conditions. It helps in deciding the shelf life and storage requirements.

Factors Affecting Stability

Light and Temperature
Moisture and Hydrolysis
Oxidation

Methods of Stability Testing

Real-time Stability Testing: Studies the actual behavior of drugs under normal storage conditions (e.g., 25°C / 60% RH) over months or years.
Accelerated Stability Testing: Uses higher temperature (40°C ± 2°C) and humidity (75% ± 5% RH) to speed up degradation and predict shelf life within 3-6 months.
Intermediate Stability Testing: Conducted at 30°C / 65% RH when accelerated results are unsatisfactory.
Stress Testing: Studies the effect of extreme conditions (very high temperature, light exposure, oxidation) to identify degradation products.

Patenting and Regulatory Requirements

1. Patents

A patent is a legal right granted by the government to an inventor for a new invention. It gives the inventor exclusive rights to make, use, or sell the invention for a limited period, usually 20 years.

What Can Be Patented: New products (drugs, devices), new processes, or improvements to existing ones.
Importance: Protects work, encourages innovation, and provides commercial benefits.

2. Intellectual Property Rights (IPR)

IPR are legal rights for intellectual creations. They protect creators against unauthorized use and encourage research.

Classification of IPR

Patent: Protects new inventions for 20 years.
Copyright: Protects literary, artistic, and musical works for the author’s lifetime plus 60 years.
Trademark: Protects brand identity (logos, slogans) for 10 years (renewable).
Industrial Design: Protects the appearance or shape of a product (e.g., a tablet strip) for 10 years.
Trade Secrets: Protects confidential business information like manufacturing formulas.

Schedule Z: GMP for ASU Drugs

Schedule Z lays down Good Manufacturing Practices (GMP) for Ayurvedic, Siddha, and Unani (ASU) drugs.

Main Requirements: Premises must be clean, hygienic, and located away from pollution.
Facilities: Must include proper washing, waste disposal, and clean water.
Workers: Must maintain personal hygiene and be free from contagious diseases.
Records: Mandatory record-keeping for manufacturing, testing, and distribution.
Importance: Prevents contamination, maintains uniform quality, and is mandatory for licensing.

Schedule T: GMP for Indian Systems of Medicine

Schedule T (part of the D & C Rules, 1945) specifies GMP for the Indian Systems of Medicine (ISM), including Ayurveda, Siddha, and Unani. It ensures medicines are manufactured under controlled, hygienic conditions.

Objectives and Components of GMP

To ensure quality, safety, and purity.
To prevent contamination and sub-standard products.

GMP involves 15 core areas, including Location, Building, Water Supply, Waste Disposal, Storage, Working Space, Equipment, Health of Workers, Batch Records, Quality Control, and Standard Operating Procedures (SOPs).