Aromatic Waters

Aromatic Waters or Medicated Waters as defined by the USP, “is a clear saturated aqueous solutions (unless other specified) of volatile oils or other aromatic or volatile substances.” Their odors and tastes are the same as those of the drugs or volatile substances from which they are prepared, and should be free from empyreumatic (smoke-like) and other foreign odors. They are in general used as flavored and perfumed vehicles. Volatile substances used for the preparation of aromatic waters should be of pharmacopoeial quality or of best quality if finest flavor is desired in case of unofficial preparations.

Preparations of Aromatics Waters

Aromatic waters are prepared either by distillation or solution.

1. Preparation by Distillation
   It is the slowest and most expensive of the two methods, however it is the most ancient and satisfactory method for making this class of preparations.
   
   
   Procedure of Distillation:
   Place the odoriferous portion of the plant or drug in a suitable still with sufficient purified water and distill most of the water, avoiding the development of empyreumatic odors through the charring or scorching of the substances. Separate the excess of the oil form the distillate and preserve or use the clear water portion, filtering if necessary.
   In Orange flower or Rose water where the flavor or odor are in small amount and delicate, the distillate is returned several times to the still with fresh portions of flowers, consequently the waters produced are commercially known as double distilled, triple distilled, or quadruple distilled according to the number of re-distillation. This process is known as cohobation.
   
   
   
   
2. Preparation by Solution
   There are two method of preparation by solution for aromatic waters, which are Direct Solution or Alternate Solution method.
   
   
   A. Direct Solution Method
   It is done by shaking two grams or 2 ml (if liquid) of the volatile oil substance (suitably comminuted if a solid) with 1000 ml of purified water in a container of sufficient capacity. Repeat the shaking several times during a period of 15 minutes. Set aside for 12 hours or longer, filter through wetted filter paper and add purified water through the filter to make the product measure 1000 ml.
   
   
   This method saves time and equipment. However, agitation is not recommended when the excess of volatile oil is allowed to remain while the water required is drawn off.
   
   
   B. Alternate Solution Method
   It is done by incorporating thoroughly the volatile oil (or the suitably comminuted volatile solid) with 15 g of talc or with a sufficient quantity of purified siliceous earth or pulped filter paper. Agitate the mixture several times during 10 minutes with 1000 ml of purified water. Filter, return first portion if necessary to obtain clear filtrate. Add sufficient amount of purified water through the filter to make the product measure 1000 ml.
   
   
   By this process water can be prepared promptly with only 10 minutes agitation thus it is the process most frequently employed.
   
   
   Talc, purified siliceous earth, or pulped filter paper classified as dispersing agent greatly increases the surface of volatile substances, insuring more rapid saturation of the water and forms an efficient filter bed, thus producing a clear solution.
   
   
   Magnesium carbonate was formerly used as dispersing agent but its slight and basic nature produced alkaline water which precipitates alkaloids and similar substances. Likewise objectionable are the use of calcium phosphate, kaolin, pumice, charcoal, precipitated chalk because calcium ion present in water dissolves slight quantity of very slightly soluble phosphates (or other slightly soluble calcium salts) form insoluble salts with many anions. Charcoal and other adsorbent tend to remove odoriferous principles.
     
   Other methods which have been suggested for the preparation of aromatic waters are:

• The use of soluble concentrates such as soluble Rose fluid.
• Incorporation of solubilizing agents as Polysorbate 80 or Tween 20.

Water prepared by these two methods are susceptible to mold growth and in concentrations higher than 2% impart an objectionable oil taste. 

• Use of aqueous alcoholic solutions of volatile oil.
  

The concentrated waters contain 20 ml of volatile oil per liter of solution and sufficient alcohol to produce ethanol content of 51 to 55% v/v. From this aromatic water can be prepared by diluting the solution with 39 times its own volume of water. Aromatic waters prepared by these methods are slightly inferior than those made by the official processes.

Incompatibilities

The difficulty encountered in the compounding of prescriptions containing aromatic waters is due to a “salting out” action of certain ingredients, such as very soluble salts in the volatile principle of the aromatic water. In such cases, a replacement of a part of the aromatic water with purified water is permissible when it has no other function than that of vehicle or a dilution of the product with a suitable increase in dosage is indicated.

Preservation

Aromatic waters should be made in small quantities and protected from intense light and excessive heat as they deteriorate with time. Deterioration may be caused by volatilization, decomposition or mold growth resulting to solution that are cloudy and have lost all traces of their agreeable odor.

It is a well-known fact that ordinary distilled water is usually contaminated by mold producing organism and therefore to avoid the presence of microorganism in water the recently boiled, distilled water is preferably used.

 

Examples of Aromatic Water

1. Cinnamon Water NF – It is a clear, saturated solution of cinnamon oil in purified water prepared by either of the official processes. It can be used as a flavored vehicle.
   
   
2. Orange Flower Water NF – It is a saturated solution of the odoriferous principles of the flowers of Citrus Aurantium Linne (Family Rutaceae). The fresh flowers with water are distilled. Then the excess volatile oil is separated from the clear water portion of the distillate. It is nearly colorless, clear or only faintly distillate. It is nearly colorless, clear or only faintly opalescent with an odor of orange blossom. It must be free from empyreuma, mustiness, and fungoid growth. It can be used as a flavor vehicle and perfume in solutions, syrups and elixirs.
   
   
3. Peppermint Water USP – It is a clear, saturated solution of peppermint oil in purified water, prepared by either of the official processes. It can be used as a flavored vehicle and carminative. The usual dose may be given 15ml.
   
   
4. Strong Rose Water NF – It is a saturated solution of the odoriferous principles of the flower of Rosae centifolia Linne (Family Rosacease). The fresh flowers with water are distilled, then the excess volatile oil is separated from the clear water portion of the distillate.
   
   
   Notice: When Rose Water is required, dilute Stronger Rose Water with an equal volume of purified water.
   
   
   Like other waters it is nearly colorless and clear liquid, possessing the pleasant odor and taste of fresh rose blossoms but free from empyreuma, mustiness, and fungal growth. This can be used as perfumed vehicle in Rose Water Ointment.