PERMETHRIN CREAM IN THE TREATMENT OF SCABIES OR PEDICULOSIS PUBIS
(5% hydrophilic cream)
Permethrin is a synthetic pyrethroid used as a topical scabicide and pediculicide. Structurally, it is similar to pyrethrum, a natural insecticide obtained from the Dalmatian chrysanthemum (Chrysanthemum cinerariaefolium) of the Compositae family. It differs from it by being longer-acting. Permethrin is used in household insecticide sprays and fogging products, dips and sprays used to rid cats and dogs of fleas, decorative garden and lawn products, repellent/insecticide preparations used for clothing, products used to reduce mosquitoes, preparations used against termites, agricultural pesticide products, shampoos used against lice, and body lotions used to control scabies.
Permethrin 5% cream or lotion, which is first-line treatment, is applied thoroughly by rubbing into the body after washing and is washed off after 12 hours. It exerts its effect by disrupting nerve transmission, causing paralysis. Applying 30 grams is sufficient for an average adult. Total absorption for permethrin over 48 hours is 0.7% of the amount applied to the body. Permethrin is metabolized by skin esterases and eliminated by the kidneys within 72 hours. Its metabolism and excretion are faster than its absorption through the skin; therefore, its accumulation in the skin does not occur. Side effects are quite rare. The most common side effects are localized burning sensation, irritation, and tingling, but they are usually short-lived and rarely cause contact dermatitis. Permethrin can be used in neonatal scabies. A cure rate of 97.8% with a single application of permethrin has been reported. Permethrin was found to be more effective than crotamiton and lindane. Applying two consecutive applications of permethrin increases its efficacy. Treatment should be repeated 1–2 weeks after the first application. Its pregnancy category is B.
In scabies treatment, if the disease is left untreated, itching may persist for weeks or months. The entire family or cohabitants must be included in the treatment alongside the patient. Immediately after treatment, itching may not disappear, contrary to expectations. The patient should be informed that the itching will gradually subside and advised to avoid frequent treatments and irritating washes. It is important to provide patients with written information explaining the medication to be applied, the amount of application, the method of application, and precautions to be taken. First, a bath with soap and water is taken. The cream or lotion should be applied to the entire skin, starting from the nape of the neck and behind the ears, including all folds, groins, navel, genital area, and under the nails. In patients with classic scabies, facial treatment and application to the scalp are controversial. There are also views advocating that medications should be applied to the entire skin except around the eyes. In infants, the facial skin should also be treated due to contact during breastfeeding. Hands should not be washed after applying lotion/cream; if washed, the medication should be reapplied. If the medication is applied by someone who does not have scabies, disposable gloves should be worn.
Permethrin formula for the treatment of scabies or pediculosis pubis.
Rp.
Permethrin 2.5 g
Cetomacrogol 1000 2.4 g
Cetostearyl alcohol 5.1 g
White Petrolatum 7.5 g
Liquid paraffin 3 g
Distilled water q.s. 50 g
Substances used in the formula:
Permethrin- Permethrin [ABDATA-SK; ASK; BAN1999; INCI; INN; USAN]- Permethrine [DCF; INN]- Acticin [TN];
It has the appearance of colorless crystals. Insoluble in water. Permethrin is effective over a broad spectrum against lice, ticks, fleas, and similar pests. Permethrin exerts its effect by disrupting sodium channels that regulate membrane polarization in the nerve cell membranes of these organisms. As a result of delayed repolarization and subsequent paralysis, the insect dies. Permethrin is applied topically. When its 5% cream is used in patients with moderate to severe scabies complaints, it is estimated that less than 2% of the applied drug is absorbed. The absorbed drug is rapidly converted into inactive metabolites through ester hydrolysis and excreted in the urine.
Cetomacrogol 1000- Anionic emulsifying wax- Cera emulsificans- Nonionic emulsifiying wax;
It is generally used as an ointment base, solubilizer, and emulsifying agent in food, cosmetics, and pharmacy. It is used as an oil-in-water (O/W) emulsifier and wetting agent for creams/lotions. Emulsifying waxes are used as emulsifying and stiffening agents in pharmaceutical preparations and cosmetic products. Emulsions containing anionic emulsifying wax at a 2% concentration are fluid, while those containing 10% are viscous. Anhydrous ointment bases are prepared using 3–30% anionic emulsifying wax together with soft and liquid paraffins. When emulsifying wax is added to cocoa butter at 10%, a suppository base with a melting point of 34°C is obtained. The anionic emulsifying wax included in the British Pharmacopoeia (BP) contains cetostearyl alcohol and sodium lauryl sulfate or sodium salts of similar sulfated higher primary aliphatic alcohols. The nonionic emulsifying wax registered in the United States National Formulary (USNF) contains cetostearyl alcohol and a polysorbate. Cetyl and stearyl alcohols are reported to be non-toxic. Anionic emulsifying wax is found as a white or pale yellow waxy solid or flakes. It has a faint, characteristic odor. It becomes plastic when heated. Practically insoluble in water, but can form emulsions; soluble in alcohol, ether, and chloroform; soluble in fixed oils and liquid paraffin when heated.
Cetostearyl alcohol- Cetyl stearyl alcohol- Cetostearyl alcohol [BP; NF; P.Cx.79]- Cetylstearylalkohol [ASK; Ph.Eur.]- Lanette(R) O;
Cetostearyl alcohol is used in creams, ointments, and other topical preparations as a stiffening agent and emulsion stabilizer. Combined with hydrophilic emulsifying agents, it is useful in preparing oil-in-water emulsions that remain stable across a wide pH range. It is also used to enhance the emollient effect of ointments prepared with paraffin. Although it is essentially a non-irritant substance, hypersensitivity reactions related to its main components, cetyl and stearyl alcohol, have been reported. Cetostearyl alcohol is a mixture of solid aliphatic alcohols consisting mainly of cetyl alcohol and stearyl alcohol. It is obtained by the reduction of suitable fatty acids. The British Pharmacopoeia (BP) and the United States National Formulary (USNF) state that it should contain not less than 90% cetyl+stearyl alcohol and not less than 40% stearyl alcohol. Cetostearyl alcohol occurs as a white or pale yellow waxy mass with a faint characteristic odor, or as white flakes or granules. When heated, it melts to yield a colorless or pale yellow liquid free from cloudiness or suspended particles. Practically insoluble in water; freely soluble in ether; soluble in alcohol and petroleum ether. When melted, it is miscible with fixed oils, liquid paraffin, and melted lanolin.
White Petrolatum- Officinal vaseline- Paraffin, soft, white [BP; P.Cx.79]- Petrolatum, white [NF; USP]- Vaselin, weisses [PH; Ph.Eur.]- Weisses Vaselin [ASK];
Petrolatum is included in the composition 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 carries may cause allergic reactions. The amount of these impurities depends on the source and purification degree of petrolatum. Hypersensitivity reactions caused by white petrolatum are less frequent than those from yellow petrolatum. Therefore, white petrolatum is preferred in cosmetic products and pharmaceutical preparations. Petrolatum is obtained from petroleum. It is a purified mixture of semi-solid saturated hydrocarbons with the general formula CnH2n+2. It is the bleached form of yellow petrolatum. It is a white, translucent, soft-consistency mass. Odorless and tasteless. 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, dry place. It should be protected from light. Petrolatum is quite a stable substance. However, it may cause stability problems due to minute amounts of impurities it contains. These impurities may oxidize under the influence of light to cause discoloration. As a result, undesirable odors may arise. Such oxidations can be prevented by adding an antioxidant such as butylated hydroxyanisole, butylated hydroxytoluene, or alpha-tocopherol. It should not be heated for long periods above the temperature required to make it completely fluid (approximately 70°C).
Liquid paraffin- Liquid petrolatum- Mineral oil- Liquid vaseline- Dickflüssiges Paraffin [ASK]- Mineral oil [INCI; NF; NF16; USP]- Paraffin, dickflüssiges [Ph.Eur.]- Paraffinum liquidum [INCI; EU];
Liquid paraffin is heavily used in topical pharmaceutical preparations. It is included in the composition of ointment bases to benefit from its emollient properties. It is used in oil-in-water emulsions. It is used as a lubricant in tablets and capsules. Due to its lubricant property, it is also used in ophthalmic formulations. Liquid paraffin is a mixture of saturated liquid hydrocarbons obtained from petroleum. It is a transparent, colorless, odorless, and viscous liquid. It exhibits no fluorescence in daylight. It is a tasteless and odorless substance, but emits a faint odor when heated. Practically insoluble in water, glycerin, and alcohol; soluble in benzene, acetone, chloroform, ether, carbon disulfide, and petroleum ether. It is miscible with most volatile and fixed oils (except castor oil). The addition of small amounts of surfactant provides increased miscibility/solubility. It should be stored in airtight containers and protected from light.
Distilled water – Purified water- Aqua [INCI-EU]- Gereinigtes Wasser [ASK]- Wasser, gereinigtes [Ph.Eur.]- Water, purified [BP; NF; USP];
Distilled water is high-purity water prepared by the distillation of potable water and used as a solvent or vehicle in many pharmaceutical formulations. It is a clear and colorless liquid with no characteristic odor or taste. In pharmacy, when water is mentioned, distilled water should be understood. The shelf life of distilled water is limited. In any case, it must be boiled before use. Because additional properties are required for water to be used in parenteral preparations, water for injections should be used for this purpose. In addition, deionized water may also be used instead of distilled water in pharmaceutical preparations where its use is permitted because it is cheaper and more easily obtained.
Preparation of the formula:
The tare of an evaporating dish is taken. The active ingredients are weighed individually. In the dish, 2.4 g cetomacrogol 1000, 3 g liquid paraffin, 5.1 g cetostearyl alcohol, and 7.5 g white petrolatum are melted by heating in a water bath at a temperature of approximately 70 °C. To this melted oily phase, 2.5 g permethrin is added and stirred until completely dissolved. Meanwhile, 29 g of distilled water is heated in a beaker to a temperature of approximately 75 °C. The aqueous phase is added to the melted oily phase at approximately 75 °C and stirred until a semi-solid cream is obtained. Taking into account the tare of the dish, it is made up to 50 g with water. The formula should be stored at a temperature between 15 °C and 25 °C. Beyond-use date is 2 months (7 days without preservative).
If it is to be applied for the treatment of pediculosis of the scalp, a cream containing 1% permethrin should be prepared.
In the treatment of scabies, the cream must be applied to clean, dry skin. Avoid using it around the mouth and eye areas.
In adults and children over 12 years of age; no more than 60 g should be applied. In children under 12 years of age; the approximate amount of cream to be used in a single application is indicated in the table below.
In children from 2 months to 1 year of age, 3.75 g
In children between 1 and 5 years of age, 7.5 g
In children between 6 and 12 years of age, up to 15 g may be used.
In cases where treatment of the head, neck, scalp, and ears is required, the dose may be increased to cover the entire body.
Source:
- FORMULAIRE THERAPEUTIQUE MAGISTRAL Edition 2010
- RxMediaPharma® Interactive Drug Information Resource 2021
Exp. Pharm. Ahmet Nezihi Pekcan
Pekcan Pharmacy – Konya
[email protected]
Tel: (332) 3520657
http://www.majistralformul.com/
