Formula:
Rp.
Bismuth subgallate 33.3 g
Zinc oxide 33.3 g
Rivanol 1.7 g
Lanolin 83.4 g
Vaseline 148.3 g
Ingredients in the formula:
Basic bismuth gallate- Dermatol- Bismutum subgallicum [PH6]- Sous-gallate de bismuth [FP]:Bismuth subgallate exhibits weak antiseptic and astringent effects when applied externally. It is generally used as a wound powder. The United States Pharmacopeia (USP) defines bismuth subgallate as Bi2O3 dried at 105°C for 3 hours. It is an odorless, amorphous, bright yellow powder. It is practically insoluble in water, alcohol, chloroform, ether, and dilute mineral acids; dissolves with decomposition in moderately dilute hot hydrochloric, nitric, or sulfuric acid; and dissolves in alkali hydroxide solutions to form a clear yellow solution that rapidly turns dark red.Zinc oxide- Zinci oxide- Oxyde de zinc- Zinkoxid [ASK; Ph. Eur.]:Zinc oxide is a white or yellowish-white, odorless, amorphous, soft, particle-free powder. It slowly absorbs carbon dioxide from the air. It is practically insoluble in water; soluble in dilute mineral acids. Zinc oxide is a mild astringent with weak antiseptic properties. It is used topically to provide protection against sun rays. In such preparations used for photoprotection, it is often combined with titanium dioxide. In addition, it is applied topically in cases of eczema, abrasions, burns, friction-induced skin damage, diaper rash, and mild skin irritation. Since it is insoluble in water, it is applied in the form of powder, ointment, or paste. Zinc oxide ointment contains 20% and zinc oxide paste contains 25% zinc oxide. Calamine is a skin antiseptic containing 98% zinc oxide. Zinc oxide is also used in combination with coal tar or ichthammol in the treatment of eczema.
Zinc oxide is also included in the composition of dental cement used as a filling material in dentistry. When mixed with phosphoric acid, it forms a hard material consisting largely of zinc phosphate; the mixture of this material with clove oil and eugenol is used in the preparation of temporary fillings. Zinc exhibits astringent and weak antiseptic effects when applied topically. In addition to its astringent and antiseptic effects, zinc sulfate is also used in the form of an ophthalmic solution to clear mucus from the outer surface of the eye. However, it also causes mild vasodilation and has no decongestant effect. Zinc oxide is applied topically. Since it is insoluble in water, it is used as a skin antiseptic in the form of powder, ointment, or paste. Zinc oxide ointment contains 20% and zinc oxide paste contains 25% zinc oxide. Zinc oxide is not absorbed through the skin.Ethacridine lactate- Ethacridine lactate [BANM; INN]- Rivanolum- Acrinol lactate- Ethacridini lactas monohydricus [Ph. Eur. 4]:According to the European Pharmacopoeia (Ph. Eur. 7), ethacridine monolactate is a yellow, crystalline powder. It is sparingly soluble in water, very slightly soluble in alcohol, and practically insoluble in dichloromethane. The pH of a 2% aqueous solution ranges between 5.5 and 7.0. It must be protected from light. Rivanol (ethacridine lactate) is a yellow acridine dye. It is used as a skin antiseptic in the form of 0.01-0.2% solutions or ointments. It exhibits a strong bactericidal effect, particularly against Gram-positive bacteria. Rivanol disrupts DNA synthesis by intercalating between base pairs in the bacterial DNA helix. Its antibacterial effect is due to this disruption of DNA synthesis. Rivanol is applied topically to the skin. Rivanol should be stored in airtight containers between 15-30°C. Protect from light.Lanoline- Graisse de laine- Adeps lanae- Refined wool fat- Lanae cera- Lanoleine T.K.:Lanolin is an ointment base. It is widely used in topical pharmaceutical formulations and cosmetic products. It is used in the preparation of water-in-oil creams and ointments. When mixed with suitable vegetable oils or petrolatum, emollient creams that penetrate the skin are obtained. It mixes with water without phase separation, forming stable emulsions. Due to this property, it facilitates drug absorption. Lanolin mixes with approximately twice its weight of water without phase separation and yields stable emulsions. It is obtained from sheep’s wool. It is pale yellow in color and has an ointment-like consistency. It is soluble in ether, petroleum ether, chloroform, and boiling absolute alcohol. It is an emulsifier. It forms water-in-oil emulsions. In its anhydrous state, its consistency is quite firm. With the addition of water, a paste-like texture is formed. It is easily absorbed by the skin and is odorless. It is used as a base. According to the United States Pharmacopeia (USP), its melting range is between 38-44°C. The USP permits the inclusion of up to 200 ppm of a suitable antioxidant. 10 g of lanolin must retain at least 20 ml of water. It is practically insoluble in water; slightly soluble in cold alcohol, freely soluble in boiling alcohol. It is readily soluble in benzene, chloroform, ether, and petroleum ether. It may undergo slow autoxidation during storage. To prevent this, the addition of butylated hydroxytoluene (BHT) is permitted. Upon prolonged heating, its color darkens and an unpleasant odor may develop. The base designated as lanolinum by the Turkish Pharmacopoeia (T.K.) contains 13 parts lanolin, 3 parts liquid paraffin, and 4 parts water.White petrolatum- White vaseline- White soft paraffin- Paraffin, soft, white [BP; P.Cx.79]- Petrolatum, white [NF; USP]- Vaselin, weisses [PH; Ph.Eur.]- Vaseline, white [FP]:Petrolatum (Vaseline) is used in the formulation of topical pharmaceutical preparations as an emollient ointment base. It is not easily absorbed through the skin. It is also used in creams, transdermal preparations, and cosmetic products. Hypersensitivity reactions related to its topical use have been reported. Polycyclic aromatic hydrocarbon impurities it contains may cause allergic reactions. The amount of these impurities depends on the source of the petrolatum and the degree of purification. Hypersensitivity reactions caused by white petrolatum are less frequent than those caused by yellow petrolatum. For this reason, white petrolatum is preferred in cosmetic products and pharmaceutical preparations. Yellow petrolatum is obtained from petroleum. It is a purified mixture of semi-solid saturated hydrocarbons with the general formula CnH2n+2. Yellow petrolatum is a pale yellow or yellow, translucent mass with a soft consistency. It is odorless and tasteless. It is practically insoluble in acetone, alcohol, glycerin, and water; soluble in benzene, carbon disulfide, chloroform, ether, hexane, and numerous fixed and volatile oils. The United States Pharmacopeia (USP) permits the addition of a suitable stabilizer to its formulation. It should be stored in well-closed containers in a cool and dry place. It must be protected from light. Petrolatum is quite a stable substance. However, it can cause stability problems due to the trace amounts of impurities it contains. These impurities may oxidize under the effect of light, leading to discoloration. As a result, undesirable odors may develop. Such oxidations can be prevented by the addition of an antioxidant such as butylated hydroxyanisole, butylated hydroxytoluene, or alpha-tocopherol. It should not be heated for extended periods above the temperature required to render it completely fluid (approximately 70°C).Preparation of the formula:After thoroughly crushing the rivanol in a mortar, an equal amount of bismuth subgallate is added and mixed thoroughly. By making additions each time equal to the total amount of substance in the mortar, a homogeneous mixture of bismuth subgallate and zinc oxide with rivanol is achieved(geometric dilution). Then, petrolatum and lanolin melted in a hot water bath are added gradually, mixing after each addition.
Mortars and spatulas are most commonly used for mixing small quantities in a pharmacy setting. The mixing process in mortars is carried out on the principle of geometric dilution. The process of combining equal amounts of fine powders to ensure uniform distribution is calledgeometric dilution.
Wishing you a good week…
Source:
1- Republic of Turkey Ministry of Health and Social Assistance, General Directorate of Pharmaceuticals and Pharmacy, Standard Guide for Magistral Formulas (1985)
2-RxMediaPharma®2016 Interactive Drug Information Source.
Specialist Pharmacist Ahmet Nezihi Pekcan
Pekcan Pharmacy – Konya
[email protected]
Tel: (332) 3520657http://www.majistralformul.com/
