Medicinus - Dexa Medica

ples of these are: caryophilli flos, chamomile flowers,
peppermint leaves, etc.
Caryophylli flos, is a drug consist of the dried
buds, dark brown, 12–17 mm long, and has a strongly
aromatic odor, pungently spicy. The drug constituents
are: 15% to more than 20% essential oil with
eugenol as the main component, a little eugenol
acetate, β-caryophyllene and its oxide, α humulene
and its epoxide, flavonoids (quercetin and kaemferol
derivatives), tannins, Gallic acids and sterol glycosides.
5 The drug is used primarily as a spice. The essential
oil has marked antibacterial activity and used
as an antiseptic in dentistry.
Besides these single herbal drugs, a few of which
may also be intended for internal use in powder
form, e.g. cucurbita seeds, ratanhia root, etc., in
practice herbal mixtures also have a major role to
play. These are mixtures which are either prepared
in the pharmacy or industrially, comprising several
drugs often belonging to the same indication group,
to which are added other drugs which assist the action
or are included to correct the taste. It is a good
pharmaceutical rule that herbal mixture should consist
of only a few, about 4–7 drugs. The composition
of herbal mixtures with 20–30 drugs, which are prepared
by a number of manufactures, represents an
attempt at treatment with many drugs below therapeutically
useful levels, which is likely to be of little
help. If the dosage forms consisting of herbal mixtures
is consumed by a patient, the patient would
receive a lot of active substances, each of which has
different pharmacological effects.
The choice of the extraction solvents is an important
factor in finished product quality, and the choice
of drug is pivotal. The drug must first be thoroughly
checked before extraction as far as botanical, phytopathological,
and chemical aspects are concerned.
One needs to consider that plants normally contain
several active substances, and in certain ratio to one
another. Present regulations require that this ratio
be kept, within narrow limits, constant from one
preparation to another, which means starting from
an already standardized raw material. To attain this
objective, if the plant to be extracted is still harvested
in the wild, the area of origin, time of harvesting, the
condition of drying and of storage must be specified,
and in the extraction stage several batches must be
combined to achieve a homogeneous mix.
The extraction of a drug is the separation by
physical or chemical means of a solid or liquid material
from a solid. Normally, when an operation is
performed with solvents for extracting the vegetable
material, it is called solid/liquid extraction. Every
extractive procedure that leads to concentration
equilibrium stops when the distribution of extract-
able substances between solvent and residual drug
is constant. The parameters influencing extraction
are:
1. Swelling of the drug
Pretreatment of the ground drug with solvent
outside the extractor is a rule indispensable, to
avoid sudden swelling of the drug, to ensure
uniform moistening at the material, and to increase
the porosity of the cell wall.
2. Diffusion, pH, particle size and temperature
For the extraction of a substance from vegetable
material the solvent must diffuse into the cell
and in its turn the substance must be sufficiently
soluble in the solvent. Equilibrium will be established
between solute and solvent, the speed
of with which it is attained depending on temperature,
pH, and particle size.
3. Choice of extraction solvent
The ideal solvent is obviously one of that presenting
maximum selectivity, has the best capacity
for extraction in terms of coefficiency of
saturation of the product in the medium and
is compatible with the properties of the material
to be extracted. Ethyl alcohol is the solvent
of choice according to the pharmacopeias for
obtaining classic extracts such as soft, fluid and
dry extracts still widely used in pharmaceutical
formulations. As these solvents have a great extractive
power, the ideal alcohol/water ratio for
the extraction of plants woody parts or barks,
roots and seeds is about 7:3 or 8:2, whereas it
must be lower than 1:1 for extracting leaves or
aerial green parts. With an alcohol/water ratio of
1:1 it is possible to avoid the extraction of chlorophyll,
or resinous or polymeric substances that
are normally of no importance to the activity of
the extract but that greatly complicate the subsequent
stage of concentration by giving rise to
gummy precipitates that are hard to eliminate,
and push serious problems of phytopharmaceutical
formulation.
PHYTOPHARMACEUTICAL FORMULATION
technology
The formulation of phytopharmaceutical raw material
into dosage forms is a complex operation which
cannot be regarded only as a problem of pharmaceutical
technology. It is more demanding in that it
calls for close collaboration between manufacturer
and formulator especially of extract based products.
The problem of controlling extract has two aspects;
those are pharmaceutical technology and phytochemical
aspects.
The types of tests to be done on an extract are
essentially three: for the determination of the physi-
MEDICINUS 24(1), January 2011 37