Isopropyl myristate

Absorption

Dermal absorption of isopropyl myristate is predicated to be 0.00020 mg/cm2/event, which is considered a very low absorption rate . In a study, topically applied isopropyl myristate was largely retained in the stratum corneum . It was not detected in the receptor fluid of flow-through diffusion cells in in-vitro skin permeation experiments using human epidermis (stratum corneum and viable epidermis) and dermis of varying thickness .

Toxicity

Readily available information regarding the pharmacokinetics of isopropyl myristate is not available .

Description

Isopropyl myristate is odorless when pure. May be synthesized by conventional esterification of isopropanol with myristic acid.

Chemical properties

colourless liquid of low viscosity

Chemical properties

Isopropyl myristate is a clear, colorless, practically odorless liquid of low viscosity that congeals at about 5°C. It consists of esters of propan-2-ol and saturated high molecular weight fatty acids, principally myristic acid.

Chemical properties

Pure isopropyl myristate is virtually odorless, very slightly fatty, but not rancid

Occurrence

Reported found in kumquat peel oil, papaya, starfruit, plum brandy, coriander seed and loquat

The Uses of Isopropyl myristate

isopropyl myristate is an emollient, moisturizer, binder, and skin softener that also assists in product penetration. An ester of myristic acid, it is naturally occurring in coconut oil and nutmeg. Although isopropyl myristate is generally considered comedogenic, some ingredient manufacturers clearly specify non-comedogenicity on their data sheets.

The Uses of Isopropyl myristate

In cosmetic and topical medicinal Preparations where good absorption through the skin is desired. A jellied isopropyl myristate was marketed as Estergel (Merck & Co.) .

The Uses of Isopropyl myristate

Isopropyl myristate is an emollient in cosmetic and pharmaceutical bases.

Background

Isopropyl myristate is a moisturizer with polar characteristics used in cosmetics and topical medical preparations to ameliorate the skin absorption. Isopropyl myristate has been largely studied and impulsed as a skin penetration enhancer.
At the moment the primary usage for which isopropyl myristate is formally indicated is as the active ingredient in a non-prescription pediculicide rinse .

Indications

The primary medical indication for which isopropyl myristate is formally used as an active ingredient in a patient care product is as a non-prescription pediculicide rinse .

Production Methods

Isopropyl myristate may be prepared either by the esterification of myristic acid with propan-2-ol or by the reaction of myristoyl chloride and propan-2-ol with the aid of a suitable dehydrochlorinating agent. A high-purity material is also commercially available, produced by enzymatic esterification at low temperature.

Preparation

By conventional esterification of isopropanol with myristic acid

Definition

ChEBI: Isopropyl tetradecanoate is a fatty acid ester.

brand name

Estergel (Merck).

General Description

Isopropyl myristate is an ester of isopropyl alcohol myristic acid. It is mainly used as a solubilizer, emulsifier and emollient in cosmetic and topical medicines. It also finds applications as a flavoring agent in the food industry.
Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.

Pharmaceutical Applications

Isopropyl myristate is a nongreasy emollient that is absorbed readily by the skin. It is used as a component of semisolid bases and as a solvent for many substances applied topically. Applications in topical pharmaceutical and cosmetic formulations include bath oils; make-up; hair and nail care products; creams; lotions; lip products; shaving products; skin lubricants; deodorants; otic suspensions; and vaginal creams. For example, isopropyl myristate is a self-emulsifying component of a proposed cold cream formula, which is suitable for use as a vehicle for drugs or dermatological actives; it is also used cosmetically in stable mixtures of water and glycerol.
Isopropyl myristate is used as a penetration enhancer for transdermal formulations, and has been used in conjunction with therapeutic ultrasound and iontophoresis.It has been used in a water-oil gel prolonged-release emulsion and in various microemulsions. Such microemulsions may increase bioavailability in topical and transdermal applications. Isopropyl myristate has also been used in microspheres, and significantly increased the release of drug from etoposide-loaded microspheres.
Isopropyl myristate is used in soft adhesives for pressuresensitive adhesive tapes.

Contact allergens

Despite wide use in cosmetics, perfumes, and topical medicaments, isopropyl myristate is a very weak sen- sitizer and a mild irritant.

Biochem/physiol Actions

Isopropyl myristate (myristic acid isopropyl ester) is used to change the physicochemical characteristics of microsheres such as poly(lactic-co-glycolic acid) (PLGA) microspheres. Isopropyl myristate is used as a oil phase component in the formulaton of microemulsion systems.

Pharmacology

Isopropyl myristate is used in pharmaceutical preparations because it improves solubility and increases absorption through the skin. External uses include a non-irritating iodine preparation for disinfecting the skin (Powers & Rieger, 1963) and aerosol bactericidal preparations for feminine hygiene use without irritation of the skin and mucous membranes (Geistlich, 1970; Watson. 1969). Preparations for internal use include oral steroid formulations (Hirata, 1970) and anaesthetic injection solutions (Davis, Pearce & Connor, 1972).
Veterinary medications containing isopropyl myristate include oral or parenteral compositions for lungworm infections (N. V. Philips' Gloielampenfabrieken, 1964) and a spray formulation for bovine udders to treat mastitis, combat infection and improve the general skin condition (Kraus, 1965). Isopropyl myristate has been found to be an effective repository vehicle for im injection of penicillin in rabbits and for sc administration of oestrogens in ovariectomized rats (Platcow & Voss, 1954).
In assays on human forearms, vasoconstrictor activity of ointment preparations containing 0025% betamethasone 17-benzoate in white soft paraffin was increased by the presence of isopropyl myristate (Pepler, Woodford & Morrison, 1971). Donovan, Ohmart & Stoklosa (1954) noted that the good solvent properties of isopropyl myristate might increase the therapeutic activity of formulations by the apparent alteration in particle size of the active ingredients, so that further evaluation and clinical study would be necessary before its use in extemporaneous compounding could be recommended. Studies in which the antifungal activity of paraben esters solubilized by surfactants was decreased by isopropyl myristate (Matsumoto & Aoki, 1962) indicate that the effectiveness of medicinal substances may be influenced by the presence of surfactants and oily ingredients such as isopropyl myristate.

Pharmacokinetics

Isopropyl myristate is an emollient vehicle that is effective at enhancing the penetration of other medical agents that may be incorporated into the vehicle as active agents . In one study, a 50:50 isopropanol-isopropyl myristate binary enhancer synergistically increased the transport of estradiol across a two-layer human epidermis in vitro .

Side Effects

Thrapecylate myristate is a medicine used to treat head lice infestations in adults and children 4 years of age and older. Common side effects include skin irritation, rash, and contact dermatitis.

Safety

Isopropyl myristate is widely used in cosmetics and topical pharmaceutical formulations, and is generally regarded as a nontoxic and nonirritant material.
LD50 (mouse, oral): 49.7 g/kg
LD50 (rabbit, skin): 5 g/kg

Synthesis

Isopropyl myristate is synthesized by conventional esterification of iso-Propanol with Myristic acid.

Metabolism

Higher molecular weight aliphatic esters are thought to be readily hydrolysed to the corresponding alcohols and acids which are then metabolized; isopropyl myristate is undoubtedly hydrolysed to normal metabolic products (Fassett, 1963). When myristic acid (as the ethyl ester) was fed to dogs,

Metabolism

Any isopropyl myristate that is absorbed is likely to be hydrolyzed to its component compounds of isopropylalcohol and myristic acid .

storage

Isopropyl myristate is resistant to oxidation and hydrolysis, and does not become rancid. It should be stored in a well-closed container in a cool, dry place and protected from light.

Incompatibilities

When isopropyl myristate comes into contact with rubber, there is a drop in viscosity with concomitant swelling and partial dissolution of the rubber; contact with plastics, e.g. nylon and polyethylene, results in swelling. Isopropyl myristate is incompatible with hard paraffin, producing a granular mixture. It is also incompatible with strong oxidizing agents.

Regulatory Status

Included in the FDA Inactive Ingredients Database (otic, topical, transdermal, and vaginal preparations). Used in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.