The document outlines protocols for testing the stability of herbal drugs, including selecting representative batches, developing analytical methods using marker compounds, establishing acceptance criteria, and evaluating changes over storage like hydrolysis, oxidation, and isomerization that may occur. It discusses challenges in stability testing due to complex constituents in herbal medicines and different harvesting times for combination products. The protocols are meant to standardize testing and determine shelf life for herbal drugs as for conventional medicines.

1. PROTOCOLS FOR TESTING OF HERBAL
DRUGS
PREPARED BY-
ZULIE SHINGALA,
GUIDE- MR. BHAVIK CHAUHAN,
ASSISTANT PROFESSOR ,
FACULTY OF PHARMACY, MSU BARODA.
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2. • WHO has defined herbal medicines as finished labeled
medicinal product that contain an active ingredient, arial or
underground parts of the plant or other plant material or
combinations.
• According to a report of WHO , about 80% of the world
population is reported to rely on traditional medicine for their
primary health care needs.
• A report of global survey on national policy on traditional
medicine and regulation of herbal medicines indicated that
about 50 countries including China, Japan and Germany have
their national policy and laws on regulations of traditional
medicines.
• Herbal drugs posses a long history of its use and better
patient tolerance.
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3. • These sre cheaper and easily available in India due to rich
agriculture conditions.
• Reckless utilization of resources threatens the sustainability of
several plant species.
• in 1993, the guidelines for safety and efficacy of herbal
medicines developed by an expert committee directed that
the procedures for allopathic drugs should be followed for all
traditional and herbal products to enter into clinical trials for
any therapeutic condition.
• The quality of the trial drugs has to be tested for batch to
batch uniformity of the active cnstituents.
• However, in order to further widen their acceptance, clinical
trials of these herbal products should be encouraged.
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4. PROTOCOLS FOR STABILITY TESTING
1) Selection of batches and samples
2) Analytical procedure
3) Acceptance criteria
4) Storage conditions and storage period
5) Testing frequency
6) Evaluation
7) Statements labelling
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5. ROLE OF MARKERS
• Markers are chemically known compounds, which may or may
not have therapeutic effect, use to calculate the quantity of
herbal medicinal ingredients in herbal medicinal products.
• Finding the “right” analytical marker is a crucial need for
stability testing of HMPs. Typical sources for finding markers
are:
• Monographs and drafts (EDQM Pharmeuropa).
• Experience, transfer from other plants/constituents.
• Literature research about known constituents.
• Scientific research
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6. ANALYTICAL METHODS FOR HERBAL PRODUCTS
• The analysis of herbal preparations is mostly done by running
high performance liquid chromatography (HPLC) or gas
chromatography (GC) and thin layer chromatography (TLC)
methods, quantitative determinations by UVvisible
spectroscopy or combinations of these.
• HPLC and GC methods can be used for identification and
purity testing, as well as the detection of single compounds
for assay, is possible during one analysis.
• LC and GC mass coupling are the also tools for determination
but, they are highly sophisticated and expensive methods.
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7. • Following is the simple example of protocols for HPLC
analysis of herbal products using marker compounds-
• Liquorice (Glycyrrhiza glabra):-
• is a popular herbal medicinal product, where glycyrrhizin is
the main active component.
• A summary of protocol presented below-
1. Nine samples of liquorice were obtained from various global
market.
2. Ground samples (15gm each) were soxhlet extracted with
methanol. the extract were filtered and evaporated under a
vaccum to dryness. The residue from the extracts of each
sample was redissolved in methanol and filtered before HPLC
analysis. The methanol extracts of all nine samples were
subjected to HPLC analysis.
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8. • Glycyrrhizin (20mg/mL) in methanol was used as the
reference marker, and further dilution were made with
methanol and injected into HPLC to construct the calibration
curve.
• Retention time and the UV spectra were used to identify
glycyrrhizin, peak area was used to quantify the amounts of
glycyrrhizin presents in each sample.
• Glycyrrhizin percentage level in the sample is in the range
between 0.177 to 0.688 % w/w of dry sample materials.
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9. SHELF-LIFE
• The determination of shelf life of herbal medicinal drug
products is same as chemically defined APIs, but special
nature of herbal product should be taken into consideration.
• It is recommended that in case of a herbal medicinal product
containing a natural product or a herbal drug preparation with
constituents of known therapeutic activity, the variation in
component during the proposed shelf-life should not exceed ±
5% of the initial assay value, unless justified to widen the
range up to ±10 per cent or even higher.
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10. CHALLENGES IN STABILITY TESTING
active substances in
herbal medicinal
plants consist of
complex of
constituents.
Many herbal
compounds
are unstable.
In combined formulations,
different substances having
similar constituents give rise
to analytical challenges.
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11. SELECTION OF BATCHES
• Long term testing is to be provided with on at least two
batches of the drug substance and three batches [10] of drug
product. In some cases of combination products, it is hardly
possible to provide the required two batches of each extract
at the same time due to different harvesting times. This
should be taken into consideration when planning the
schedule for stability study.
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12. SELECTION OF BATCHES AND TESTING CONDITIONS
formal stability studies
- conducted on at least
three primary batches.
- Stability performed on
each individual strength
and container size till
bracketing. long term stability studies
- on at least three batches
performed under natural
conditions.
ongoing stability studies
- All products have to be
tested at least one batch
a year.
- Wherever appropriate,
bulk products are also to
be tested.
- Applies to every dosage
and packaging size anf
type.
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13. PREDICTABLE CHANGE IN HERBAL MEDICINAL PRODUCT
• Following predictable changes may occurs in herbal medicinal
product during storage and in shelf life determination:
Hydrolysis, Oxidation, Racemization, Geometric isomerization,
Temperature, Moisture and Light.
• Hydrolysis: Reaction with water takes place results in
degradation of product.
•
• Oxidation: Due to addition of electro negative atom (o),
Removal of electro positive atom, radicals formation results in
decomposition of natural products.
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14. • Racemization: Racemization is the process in which one
enantiomer of a compound, such as an L-amino acid, converts to
the other enantiomer. The compound then alternates between
each form while the ratio between the (+) and (–) groups.
•
• Geometric isomerization:
• Geometric isomerization: Products can be change in trans or cis
form. One form may be more therapeutically active.
•
• Polymerization: There is combination of two or more identical
molecule to form much larger & more complex molecule.
•
• Temperature: The rate of most chemical increase with increase in
temperature.
• So that “Tropical” area must be taken in consideration during
preparation of the formula of the herbal substance.
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15. • Moisture: Moisture absorbed on to the surface of solid drug
will often increase the rate of decomposition, if it is
susceptible to the hydrolysis.
• Light: Many type of chemical reaction induced by exposure to
light of high energy. Autoxidation of volatile oil / fixed oil takes
place and substance becomes colored.
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16. REFERENCE
• Challenges and guidelines for clinical trial of herbal drugs from
• www.ncbi.nlm.nih.gov
• Evidence based validation of herbal medicine by Pulok K.
Mukherjee.
• ‘Stability testing of herbal products by Anupan Kumar Sachan
and Ashutosh Kumar’ journal of chemical and pharmaceutical
research, 2015, 7(12):511-514.
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