EMULSIONS Lecturer : Plaskonis Yu. Yu.

Emulsions are homogeneous (by their appearance) medicinal forms consisting mutual insoluble thin dispersed liquids intended for internal, external application, for injections.

DEFINITION AND CHARACTERISTICS OF EMULSIONS Positive to combine immiscible liquids in one medicine; to put into the medicine’s composition the hydrophilic and hydrophobic medicinal substances; to regulate the bioavailability of medicinal substances (due to rapid and complete freeing or prolonging of the medicinal substances action); to remove irritations on the skin and mucous, which are typical for certain medicinal substances; to mask unpleasant taste and smell of some medicines. Negative instability of emulsions as dispersion systems under influencing of different factors (temperatures, air, light); the possibility of the growth of microorganisms (emulsions are favourable media for the growth of microorganisms); relatively long technological processes of manufacturing, which require the use of proper technological operations and special technological equipment; the necessity of using emulsifiers for stabilization of the dispersion system.

DEFINITION AND CHARACTERISTICS OF EMULSIONS For preparation of emulsions we use: 1.Liquids insoluble in water : Oil:peach, olive, vaseline, etc. Cod-liver oil Balm, etc. 2.Emulsifiers: HMC

An emulsion is liquid preparation containing two immiscible liquids, one of which is dispersed as globules (dispersed phase = internal phase) in the other liquid (continuous phase = external phase). To stabilize these droplets, emulsifying agent should be added

Primary and secondary emulsion: Primary emulsion containing one internal phase, for example, oil-in-water emulsion (o/w) and water-in-oil emulsion (w/o). Secondary emulsion= multiple-emulsion: it contains two internal phase, for instance, o/w/o or w/o/w. It can be used to delay release or to increase the stability of the active compounds.

TYPES OF EMULSIONS Oil-water (O/W) – direct, or I-st type (washed by water) Water-oil (W/O) – reverse, or II-d type (can not be removed by water) Water-oil-water (W/O/W) or Oil-water-oil (O/W/O)

Emulsion Type and Means of Detection: using of naked eye, it is very difficult to differentiate between o/w or w/o emulsions. Thus, the four following methods have been used to identify the type if emulsions.

1) Dilution Test: based on the solubility of external phase of emulsion. - o/w emulsion can be diluted with water. - w/o emulsion can be diluted with oil.

2) Conductivity Test: water is good conductor of electricity whereas oil is non-conductor. Therefore, continuous phase of water runs electricity more than continuous phase of oil.

= Bulb glows with O/W = Bulb doesn’t glow with W/O

3) Dye-Solubility Test: - Water-soluble dye will dissolve in the aqueous phase. - Oil-soluble dye will dissolve in the oil phase.

4-Fluorescence test: oils give fluorescence under UV light, while water doesn’t. Therefore, O/W emulsion shows spotty pattern while W/O emulsion fluoresces.

Theories of Emulsification: Incase of two immiscible liquids

Methods of formulation primary oily emulsions The method of formulation The order of mixing the substances Continental (of Bodrimon) (emulsifier + oil) + water English(emulsifier + water) + oil Russianemulsifier + (water+ oil)

Calculation of amount of components for a primary emulsion The oil’s amount is indicated in the prescription. If there are no indications, then take: 10.0 g of the oil (olive, peach or sunflower) per g of the emulsion The amount of the emulsifier is determined by its ability to emulsify The amount of water to form a primary emulsion is determined by the emulsifier’s dissolution in water

To 10.0 g of the oil add: EmulsifierWater to prepare the primary emulsion 5.0 of gelatose7.5 ml of water 2.0 of Tween ml of water 1.0 of methyl celluloseas 5 % solution g of sodium carboxymethylcellulose as 5 % solution – g of starchas 10 % solution – 50.0

Calculation of water for dilute the primary emulsion Subtract the weight of the components of the primary emulsion (oil+water+emulsifier) from the emulsion’s total weight (according to the prescription)

The scheme of technology and quality control of emulsions 1.Prescription formula 2.Verification of correctness: registration of the prescription form, prescribing and compatibility of ingredients, doses and norms of dispensing medicines 3.Calculation of the amount of medicinal and auxiliary substances 4. Formulation of emulsions: weighing, measuring, emulsification, dilution, dispersion, mixing, filtering (if necessary): Sanitary preparation of the personnel, premises and equipment Preparation of the raw material, materials, medicinal and auxiliary substances

Rp.: Emulsi olei Persicorum Coffeini-Natrii benzoatis 0.5 Misce. Da. Signa. 1 table-spoon WCP (reverse side) (as an emulsifier – solution of Methylcellulose 5 %) Peach oil: / 10 = 10.0 Solution of МС 5 %: 10.0 х 2 = 20.0 (to prepare the primary emulsion water is not required) Purified water for dilution of the primary emulsion: – ( ) = 70 ml

Place 20.0 g of 5 % metylcellulose solution in a porcelain mortar and triturate thoroughly. Then add 10.0 g of peach oil dropwise while triturating and emulsifying thoroughly. Collect the mass several times with the celluloid plate from the walls of the mortar and the pestle. Check the readiness of the primary emulsion and then add the purified water gradually. Since the emulsion contains caffeine benzoate sodium, approximately ml of the purified water (or 10 % concentrated solution - 5 ml is used) for its dissolution is left. Then dilute the primary emulsion with the remaining amount of water and add the solution of caffeine benzoate sodium.

WCP (front side) Date № Pr. Sol. Methylcellulosae 5 % 20.0 Olei Persicorum 10.0 Aq. purificatae 70 ml Coffeini-natrii benzoatis 0.5 m total = Prepared by: (signature) Checked by: (signature)

Rp.: Emulsi olei Ricini Camphorae 1.0 Misce. Da. Signa. 1 table-spoon 3 times a day. WCP (reverse side) (as an emulsifier – Tween-80) Peach oil: / 10 = 20.0 Oil phase: = 21.0 Tween-80: 21.0 / 5 = 4.2 Water for preparing the primary emulsion: 2.0 g –3 ml 4.2 g x x  5 ml Water for diluting the primary emulsion: – ( ) = ml

Weigh out 20.0 g of castor oil (Oleum Ricinum) in a porcelain cup and dissolve 1.0 g of camphor, it can be done while heating (to 40°С) on the water bath. Place 4.2 g of tween- 80 in a mortar, add an oily solution of camphor and mix. Then add 5 ml of water dropwise and emulsify until the primary emulsion is obtained. The primary emulsion prepared is then diluted by ml of the purified water, which is gradually added.

WCP (front side) Date № Pr. Olei Ricini 20.0 Camphorae 1.0 Tweeni Aquae purificatae 75.8 ml mtotal = Prepared by: (signature) Checked by: (signature)