This section is from the book "A Text-Book Of Materia Medica And Pharmacy For Medical Students", by Velyien Ewart Henderson. Also available from Amazon: A Text-Book of Materia Medica and Pharmacy for Medical Students.
With no other group of preparations is it so essential to have all solids reduced to a fine powder as with ointments, unless perchance they are readily soluble in fats. The subdivision should be so fine that when incorporated with the base no grittiness is evident to either the eye or the finger.
Ointments may be made upon an ointment slab, (the reverse of a pill tile may be used or a square of ground glass), or with mortar and pestle. The active drug is first made into a paste with a few drops of water, spirit or glycerin. It is then triturated with a small quantity of the base until thoroughly mixed. The rest of the base is then added and the trituration continued until the whole is incorporated. When completed the ointment is to be dispensed in a box or jar. This should be done cautiously so as not to smear the outside of the container and so as to leave a smooth finished surface to the ointment itself. The spatula aided by the flame of a gas or alcohol lamp over which the inverted jar is held for a moment will suffice for this.
The base selected for any ointment should be such as will fulfil the purpose of the prescription, some fats being absorbed by the skin, others not. It should be chosen with a view to avoiding chemical reaction between it and the active constituent. As already stated the chief bases are Wool Fat, Lard, and Paraffin. Their absorption by the skin and their power of absorbing liquids is in the order of mention. For extemporaneous prescriptions Wool-Fat is much more used than in the making of the official ointments.
For impressing the general system then the base should be Wool-Fat or Lard, preferably the former. This used alone makes a rather stiff ointment which is difficult to prepare and to apply. This may be avoided by the addition of a small proportion of Lard or Olive Oil.
For those to be used purely for their local effect, Soft Paraffin or a mixture of Hard and Soft, depending upon the climate, makes the ideal preparation; in cold weather less, in warm more of the Hard Paraffin is used.
The Pharmacopoeia directs the dispenser to use Yellow Paraffin if colored drugs are to be dispensed and the White for those that are colourless. This is a good rule for all but those ointments to be applied to the eye. White Paraffin is made by bleaching the Yellow with the aid of the mineral acids and there is likely to be a trace of acid present which makes it unsuited for application to the conjunctiva. For these unguents use the Yellow Paraffins. The greatest precaution to obtain ointments absolutely free of grit should be taken when for use in the eye.
The making of plasters has been so completely passed over to the manufacturing pharmacist that it seems needless to discuss the subject. Almost any formula can be had already spread by machinery with such art that the unskilled hand may not hope to obtain such perfect results from a pharmaceutical, let alone from the therapeutical, standpoint.
Those used for dispensing may be had in plain or variously coloured glass and of oval, round, or square shape. Medicines for internal use are commonly dispensed in flint or colourless bottles which are somewhat more expensive than bottles made of green glass but the better appearance makes ample return for the additional cost. Amber and blue glass bottles are in frequent use for sending out poisons and also for storing solutions which may be affected deleteriously by actinic light. Vials, for poisons, of unusual shape and studded with raised points of glass so that they may be instantly recognized, even in the dark, are advised. Prescription bottles vary in size from those containing a drachm to those holding as much as a pint or more. Cylindrical flint glass bottles holding one, two and four fluid drachms are known as homeopathic vials, and are of use in the dispensing of small quantities of eye lotions and other remedies to be administered in minute doses. For ordinary prescriptions bottles are made to contain 1/2, 1, 2, 3, 4, 6, 8, 10, 12 and 16 ounces. After the three ounce there are no odd sizes made for dispensing so that prescriptions calling for more than that quantity of fluid should be written for even numbers of ounces.
These should be of a style and shape to suit the special package to which they are attached. It is well to have two sizes for bottles. They should bear the physician's name and address, and if desired his office hours and telephone number. These items should be printed or lithographed plainly but unobtrusively, so as to leave ample space for directions to the patient. They may be already gummed if that is wished, though labels so prepared are apt to adhere in warm weather and thus become spoiled.
Labels ought to be attached so as to make the most symmetrical parcel possible, neither close to the top nor to the bottom of a bottle, but rather over the middle third of its face.
Corks for dispensing bottles should be of the longer cuts, should be kept in a moist atmosphere to prevent their becoming friable and the one used should be of such size as not to require insertion for more than half its length.
These are made of paper and are oblong, or square in shape. They may be of the well-known telescope design or have the lid lift from the base, these being the more costly. The upper surface of the cover is reserved for the label.
Made of paper and ordinarily flat and circular in shape.
These may be of wood, paper, tin or glass. The two former kinds are made impervious by preparatory treatment with a solution of silica. Glass jars may have covers of the same material, or of metal which ought to be non-corrosive. These containers are spoken of as being of 1/2,1,2, 3, 4, 6, and 8 ounce in size, as determined by the capacity of each. Those made of glass are preferable but are the most expensive. Labels are commonly applied to the upper surface of the lids but in the case of those having metal covers it may be found difficult without a special mucilage to keep them adherent. With the glass jars having metal covers this may be obviated by placing the label either upon the side or the bottom.