Mixtures in Pharmacy are
aqueous liquid preparations which contain suspended, insoluble, solid
substances and are intended for internal use. The insoluble particles may be
held in suspension by the use of suitable suspending or thickening agents since
the insoluble substance does not make mixture very viscous.
The insoluble substance in
mixtures must be in a very finely divided state and it must be uniformly
distributed throughout the preparation. This is accomplished by the use of
colloid mill, special methods of precipitation and suspending agents.
There are three main reasons
for having the insoluble substance in as fine a state of subdivision as
possible:
(1) The more nearly the
colloidal state is approached by protective such as kaolin, magnesium
trisilicate, and magnesium phosphate the more active they become as adsorbents
and protective when in contact with inflamed surfaces.
(2) Finely divided particles
are suspended more readily and settle out much more slowly than large
particles, thus enabling the patient to obtain uniform doses of suspended
substance. Homogenous mixtures are especially desirable when administering
medication to form an evenly distributed, soothing, protective coating on the
gastrointestinal tract.
(3) The palatability of many
preparations is enhanced by the use of colloidal suspending agents.
Mixtures should be accompanied
with a “Shake Well” label.
Preparation of Mixtures
Brown Mixture, NF
Other Names: Mistura Opii et
Glycyrrhizae Composita; Compound Opium and Glycyrrhiza Mixture NF XI; Mistura
Glyceyrrhizae Composita; Compound Mixture of Glycyrrhiza.
Formula:
Glycyrrhiza Fluidextract 120ml
Antimony Potassium Tartrate
0.24g
Paregoric 120ml
Alcohol 30ml
Glycerin 120ml
Purified Water, q.s.
__________
To make 1000ml
Preparation:
Mix the fluidextract with the
glycerin and 500ml of purified water, add the antimony potassium tartrate dissolved
in 12ml of hot purified water. Add the other ingredients and enough purified
water to make the product measure 1000ml.
Use: For coughs, often in
combination with ammonium chloride.
Dose: Usual, 5ml
Note: This formula in which
glycyrrhiza extract is replaced by the fluid extract will contain a
precipitate, but it is intended to be dispensed without filtering, to retain
its universally known classification as a mixture.
Kaolin Mixture with Pectin, NF
Other Name: Ka – Pek (APC)
Formula:
Kaolin 200g
Pectin 10g
Tragacanth, powdered 5g
Benzoic Acid 2g
Glycerin 20ml
Peppermint Oil 0.75ml
Purified Water, q.s. ________
To make 1000ml
Preparation:
Mix the kaolin with 500ml of
purified water. Triturate the pectin, powdered tragacanth and sodium saccharin
with the glycerin and add to this, with constant stirring, the benzoic acid
dissolved in 300ml of boiling purified water. Allow the mixture to stand until
it cools to room temperature and all the pectin is dissolved. Add the
peppermint oil and the kaolin – water mixture, mix thoroughly, and finally add sufficient
quantity of purified water to make 1000ml.
Uses: Adsorbent and demulcent.
Agents cause adsorbent in diarrhea capable of being adsorbed as for instance
diarrhea of food poisoning or dysentery.
Note: To obtain a product with
suitable consistency when larger amounts are prepared, the quantity of
tragacanth and, if necessary, of pectin may altered. However, if the proportion
of pectin in the formula is altered by more than 10 percent, the pectin content
of the preparation must be clearly stated on the label.
