Lecture Liniments
Liniment is medicinal form for external application. It is in the form of dense liquid or gelatinous masse that melts at the body temperature and is used by rubbing into the skin.
According to the State Pharmacopoeia of Ukraine: Liniments are soft medicinal forms for local application, they melt at body temperature.
Advantages and disadvantages of liniments Advantages of liniments Applied to the skin readily. High bioavailability. Absorbed quickly by the skin.
Disadvantages of liniments Low stability. Inconvenience of transportation.
Classification of Liniments by the Type of Dispersion Environment
Fatty liniment (liniment pinguia seu olimenta): fatty oils (sunflower and flax seed oils are often used) are included as a dispersion environment. Alcohol liniment (capsicum tincture and others are included as a dispersion environment). Vaseline liniment include Vaseline oil. Due to its high chemical inertness, they are very stable when stored. Siliments: silicon liquids are included as a dispersion environment. Soapy-alcohol liniment: the alcoholic solutions of soaps are included as a dispersion environment. They can be liquid (if they contain potassium soap), dense or gel-like.
Classification of Liniments by the Type of Disperse System
Liniments-solutions are transparent mixes of fatty oils with essential oils, chloroform, methyl salicylate, ester, turpentine. Prescribed medicinal matters are solved in the prescribed solvents. Liniments-suspensions are the 2 phased systems (suspensions of powdered medicinal substances insoluble in prescribed liquids). Liniments-emulsions are the 2 phased systems which can be emulsions of oil/ water or water/oil type.
General Rules for Compounding Liniments
Liniments are compounded by the general rules of liquid medicinal form compounding according to the “Instruction for compounding MF with liquid dispersion medium at the chemist shop”. Homogenous liniments are usually compounded directly in a dry vial for handling. Dense and viscous liquids (turpentine, tar, fatty oils) are dosed by weight, as well as liquids with high density (perhydrol, concentrated acids). Soluble medicinal substances are included into liniments according to their solubility in the prescribed components. They are dissolved in the solvent in which they have the best solubility and then they are mixed with other ingredients.
General Rules for Compounding Liniments
While compounding liniments suspensions, the medicinal substances insoluble in the prescribed liquids are powdered in the mortar using the Deryagin’s rule and then they are mixed with liquid components. As the dispersion environment is dense and viscous, surfactants (stabilizers) are not included into the composition of suspension liniments if they are not prescribed by the doctor. The suspension’s stability is reached due to a high viscosity of the medium.
Emulsive liniments are prepared using emulsifiers according to the general rules for compounding emulsions. In some cases, emulsion liniments are prepared in a vial for dispensing, because emulsion is formed readily. The volatile and odoriferous substances are added last.
Technology of Liniments
Particular Technology of Liniments
Liniments-solutions Different solid medicinal substances which are soluble in the prescribed liquids can be included into the composition of liniments solutions (camphor, menthol, anesthesin (less then 2%)). Rp: Chloroformii 10.0 Olei Helianthi Olei Therebinthinae aa 20.0 M.D.S: Rub into the diseased joint This medicine is a liniment-solution containing strong effective, light sensitive substance – chloroform, an odoriferous one – turpentine and light sensitive substance – sunflower oil in its composition. All 3 liquid components are soluble into each other.
WCP (back side)
WCP (front side)
m (MF) = 10.0 + 20.0 date No. of + 20.0 = 50.0 prescription Olei Helianthi 20.0 Chloroformii 10.0 Olei Therebinthinae 20.0 m (MF) = 50.0 Compounded by: Checked by: Handled by:
Rp:
Mentholi 2.0 Camphorae 3.0 Olei Helanthi 80.0 Methylii salicylatis 5.0 M.D.S: Rub into the diseased joint.
This medicine is a liniment-solution containing volatile odoriferous substances – menthol and camphor forming eutectic mixture, an odoriferous, volatile, lightsensitive substance – methyl salicylate, a light sensitive substance – sunflower oil in its composition.
WCP (back side) m (MF) = 2.0 + 3.0 + 80.0 + 5.0 = 90.0
WCP (front side) date
No. of prescription Mentholi 2.0 Camphorae 3.0 Olei Helanthi 80.0 Methylii salicylatis 5.0 m (MF) = 90.0 Compounded by: Checked by: Handled by:
Rosental paste Rp: Iodii 0.3 Paraffini 15.0 Spiritus aethylici 95% 10ml Chloroformii 80.0 M.D.S: For warm dressing The peculiarities of preparation: iodine, paraffin, chloroform by chips are placed into the vial for dispensing and covered with the lid, then put on the water bath till complete dissolution. After that the alcohol is added.
WCP (back side) m(alcohol) = V*ρ = 10 * 0.8 = 8.0 g m (MF) = 0.3+15.0+80.0+8.0 = 103.3 g
WCP (front side) date
No. of prescription Iodii 0.3 Paraffini 15.0 Chloroformii 80.0 Spiritus aethylici 95% 8.0 m (MF) = 103.3 Compounded by: Checked by: Handled by:
Rosental paste with medicinal substances Rp:
Iodi 1.0 Kallii iodidi 2.0 Paraffini 20.0 Spiritus aethylici 70% 20ml Chloroformii 80.0 M.D.S: for warm dressing
Liniments –suspensions
Such substances as zinc oxide, talc, xeroform, calcium carbonate, starch and sulfanilamide drugs are more often prescribed in the composition of liniments-suspensions . Glycerol, fatty oils, alcohol, water etc are used as a dispersion medium. A classic example of linimentsuspension is the Vishnevsky liniment or balmy liniment.
The Vishnevsky liniment composition Rp.: Xeroformii Picis liquidae Betulae aa 3,0 Olei Ricini 100,0 Misce. Da. Signa: For application on wounds
Possible substitutions of medicinal substances Dermatoli 3,0 Vinilini (Balsami Schostakovsky) 6,0 Olei Jecoris 100,0 Misce. Da. Signa: For application on wounds.
The peculiarities of this medical form compounding are: a dry substance (xeroform or Dermatol) are grinded with tar (Picis liquidae Betulae) or vinylene according to the Deryagin’s rule, then a castor oil (Oleum Ricini) or cod liver (Oleum Jecoris) are added while stirring.
WCP (back side) m (MF) = 3.0+3.0+100.0 = 106.0g
WCP (front side) date
No. of prescription Xeroformii 3.0 Picis liquidae Betulae 3.0 Olei Ricini 100.0 m (MF) = 106.0 Compounded by: Checked by: Handled by:
Liniments-emulsions
Liniments-emulsions (saponiments) are mixtures of fatty oils with alkalis or they contain the solutions of soap. An emulsifier is either indicated in the prescription or formed as a result of interaction of the components included into the composition of liniments. A typical example, which is an emulsion of oil/water type, is ammonium or volatile liniment.
Volatile liniment Rp: Olei Helanthi 74.0 Solutionis ammonii caustici 25ml Acidi oleinici 1.0 M.D.S: For rubbing This medicine is an emulsion liniment of w/o type, which contains odoriferous liquid – ammonium solution. Ammonium oleate formed as a result of the neutralization reaction serves as an emulsifier. The emulsion is formed easily while shaking two liquids with the emulsifier. This medicine compounded in the vial for handling. First, the sunflower oil is weighed and then the oleic acid and ammonia solution are added. It’s packed and shaken.
WCP (back side) m (MF) = 74.0+25.0+1.0 = 100.0g
WCP (front side) date No. of prescription Olei Helianthi 74.0 Acidi oleinici 1.0 Solutionis Ammonii 25.0 m (MF) = 100.0 Compounded by: Checked by: Handled by:
