Unmeasured forms: specifics of prescribing herbal teas
An herbal tea, designated in Latin as Species, is a classical solid unmeasured dosage form. Plant raw materials of various origins always serve as the primary material for its production. Pharmaceutical technology in this case does not require complex equipment: the specialist's main task is to thoroughly and evenly mix all dry ingredients to obtain a homogeneous mass.
Let us consider a specific example of a complex herbal tea prescription. The composition may include various plant parts: St. John's wort herb (Herba Hyperici) in an amount of twenty grams, sage leaves (Folia Salviae) weighing thirty grams, and peppermint leaves (Folia Menthae piperitae) weighing ten grams. On the prescription blank, after the traditional heading Rp.:, these names must be put in the genitive case.
The most important element of the prescription is the subscription — instructions to the pharmacist. The physician is obliged to write: M.f. species, which in full translates as Misce, fiat species (Mix, let species be made). In the signature, the physician indicates the method of administration to the patient, for example, prescribing to brew the resulting plant mass as a tea or infusion.
In addition, standard official herbal teas are widely used in medical practice, which are prescribed not by individual ingredients, but by their direct name. Such compositions include diuretic tea, which in Latin is called Species diureticae, and pectoral tea — Species pectorales. As a rule, they are prescribed immediately by total weight, most often 50.0 grams each.
Measured powders and the role of vehicles
A solid measured dosage form in the form of powder (Pulvis) requires a fundamentally different approach to prescription drafting. Unlike herbal teas, powders are intended for extremely precise dosing of active substances. In practice, a situation often arises where the therapeutic dose of the main active component is extremely small, and dispensing it in its pure form is impossible.
To solve this problem, the technology of adding a vehicle substance, or filler, which in Latin is called constituens, is used. An excellent example is the prescription for Dibazol (Dibazolum), a well-known spasmolytic and immunomodulator. Only 0.005 grams of the main active ingredient is required per single dose. To give the powder a mass convenient for oral intake, sugar (Saccharum) in the amount of 0.3 grams is added to it.
In the prescription, the physician lists the ingredients sequentially: Rp.: Dibazoli 0,005; Sacchari 0,3. This is followed by the technological instruction to mix the substances: M.f. pulvis, which means Misce, fiat pulvis (Mix, let powder be made). The prescription line concludes with the command to dispense the required number of doses: D.t.d. N. 20.
There are also complex measured powders in which several active components are mixed without explicitly indicating a filler. For example, theophylline (Theophyllinum) in an amount of 0.1 and ephedrine hydrochloride (Ephedrini hydrochloridum) at a dose of 0.025 can be combined in a single dose. The pharmacist is given a similar instruction: mix to form a powder, and dispense twenty such doses.
Complex prescriptions in tablets
Tablets also belong to solid measured forms, but they have their own design features, especially when it comes to complex multicomponent compositions. In complex prescriptions, the physician sequentially lists all active ingredients and their exact dosages, calculated strictly for a single tablet.
A striking example is the combination of three active substances: platyphylline hydrotartrate (Platyphyllini hydrotartratis) at a dose of 0.003, papaverine hydrochloride (Papaverini hydrochloridi) at a dose of 0.03, and theobromine (Theobromini) in an amount of 0.25. After listing all components, a specific prescription formulation is placed: D.t.d. N. 10 in tabulettis. The full translation of this Latin phrase is: "Dispense such doses numbered 10 in tablets. Mark [sign]."
Other tablet mixtures are prescribed in a similar manner. As yet another example, we can consider the combination of theobromine and phenobarbital (Phenobarbitali) at a dosage of 0.02. In this case, the prescription line regulating the dispensing can be written out by the physician in more detail, without abbreviations: Da tales doses numero 12 in tabulettis (Dispense such doses numbered 12 in tablets). This recording format clearly emphasizes that the patient must be dispensed exactly twelve ready-made dosage units.
Briefly: answers to topical questions
Which parts of plants can be used to prepare herbal teas?
Dried parts of plants are used to prepare herbal teas. The following can be used as plant raw materials:
- Herb (Herba) — St. John's wort, field horsetail, lily of the valley.
- Leaves (Folia) — sage, peppermint, stinging nettle.
- Flowers — German chamomile, arnica.
- Roots — valerian, Manchurian aralia.
- Rhizomes with roots — Yeddo yam (Zanichellia-leaved smilax / stemless mandate / Manchurian wild ginger - generic localization: prickly wild ginger / Zanthoxylum / Mandragora; standard: Manchurian snakeroot / Eleutherococcus/Zanthoxylum... Wait, *Заманиха* is *Echinopanax*. Let's use standard botanical: *Echinopanax* roots / rhizomes with roots).
- Fruits — rose hip, senna.
- Shoots — bilberry.
- Fruit valves — common bean.
- Bark — buckthorn.
Which substances are used as vehicles (constituens) for powders?
Various carbohydrates are used as vehicle substances (constituens) or fillers for preparing powders. These include:
- Sugar (Saccharum)
- Lactose (Milk sugar)
- Glucose
These substances are added in an amount of 0.2–0.5 g when prescribing measured powders if the dose of the active substance is less than 0.05 g. They are also used to create triturations (mixtures with milk sugar).
What types are tablets divided into depending on the route of administration and method of use?
The sources directly mention:
- Oral tablets — combined oral contraceptives.
- Sublingual tablets — used under the tongue, for example, for relieving an angina attack.
- Coated tablets.
- Prolonged-release tablets (retard).
Into what types are powders classified according to the degree of comminution?
According to the degree of comminution, the solid dosage form made of dry particles (powders) is classified into several types depending on particle size. According to the classification, the following types of powders are distinguished:
- Coarse
- Fine
- Very fine (subtilissimus) — used for making dusting powders.
- Extremely fine (longe subtilissimus) — used predominantly for insufflations.
The abbreviation "M.f." can be mnemonically remembered as the phrase "Mix Form" — this is a direct instruction to the pharmacist to mix the initial ingredients so that the required dosage form is obtained (Misce, fiat).
Class and exam questions
What is the difference between prescribing a simple and a compound herbal tea?
A compound herbal tea is prescribed by listing all plant components and their weight, followed by Misce, fiat species. Simple officinal teas (pectoral or diuretic) are prescribed directly by name with the indication of their total weight (e.g., 50.0 g).
Why is sugar indicated in a prescription for bendazol?
Dibazol is prescribed at a dose of 0.005 g — this is too small a mass for independent intake by the patient. Sugar (0.3 g) is added as a constituens (vehicle substance) to create sufficient volume and mass of the powder.
How is the phrase in tabulettis translated and when is it used?
This Latin formulation translates as "in tablets". It is added at the very end of the prescription to the standard command for dispensing doses, for example: Da tales doses numero 12 in tabulettis.
What else to study on this topic
- Grammatical rules for declining Latin names of plant parts (herb, leaves) in the genitive case.
- Features of working with potent substances in microdoses using platyphylline as an example.
- Differences between the short spelling D.t.d. N. and the full form Da tales doses numero.
- Rules for formatting the Signa prescription line for oral medications.
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