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A film coating is a thin polymer-based coat that is typically sprayed onto solid pharmaceutical dosage forms, such as tablets, capsules, pellets or granules. Film coating can impact both its appearance and its pharmacokinetics making it an essential process in making the final drug product.
Film coatings are the most common form of drug coating and are generally applied in orally-administered pharmaceuticals. The motivation for applying film coatings to dosage forms range from cosmetic considerations (colour, gloss and branding), improving the shelf life by providing a protective barrier between the drug and the surrounding environment. These types of film coatings are known as non-functional film coatings. They may also be used to delay or augment the delivery and uptake of medications or delay release and uptake until the medication passes through the stomach. These types of film coatings are known as functional film coatings.
The conventional method of applying film coatings to oral dosage forms comprises a spraying phase and a drying phase. [1] The spraying phase consists of applying a layer of a polymer, plasticizer, colourant, opacifier, solvent, and a vehicle to the oral dosage form's core. [2] Once applied, the oral dosage form is dried by passing hot air over the dosage form, which typically also removes the solvent as well. The final result is a thin film coating with the desired plasticizer, colour, opacifier, and vehicle. [1]
Non-functional film coating involves changes made to the aesthetic of the oral dosage form. Such changes affect an oral dosage form's appearance, organoleptic properties, swallowing properties, and provide protection against harsh environmental conditions that can damage the active pharmaceutical ingredient. [2] These changes are conducted to improve the compliance and effects of the oral dosage form. For instance, changing appearance can be done by changing the colour of the drug, leading to a more appealing product. [2] Changing the swallowing properties can make it easier for those suffering from dysphagia. [2] Finally, adding a film that protects from harsh environments, such conditions include humidity, oxidation, or light, increases the shelf life of the final product. [2]
Functional film coating provides the same properties as non-functional film coating, but also has added properties that affect drug release. [2] These changes alter the region in the gastrointestinal tract that the final drug product is released. [2] See modified-release dosage and enteric coatings.
Organic solvent use in film coating is typically used to incorporate protective coatings to the oral dosage form, which aids in increasing the shelf life of the final drug product. [1] This type of film coating can be dangerous due to its potential for toxicity in the final product and flammability during the film coating process. [1] As such, it is integral to have proper safety measures and ventilation in place when film coating.
Aqueous film coating is the most common film coating method currently used. [1] This type of film coating uses water to aid in the film coating process instead of organic solvents. [1] The result is a safer means of film coating, as it avoids the toxic and flammable properties of organic solvents. Aqueous film coating requires the use of water insoluble polymer mixtures, with the addition of a plasticizer. [1] Despite its widespread popularity, aqueous film coating is more time consuming than organic solvent-based coating, due to the increased time needed for complete evaporation of water. [1]
Solvent-free film coating is most commonly used in coating heat sensitive drugs due to the benefit of not requiring a drying phase. [1] The end result of this type of film coating is an inert film coating that does not react with the active pharmaceutical ingredients. [1] Some methods to create a solvent-free film coating include injection molding coating, hot-melt coating, and spray congealing. [1] Each method has its own advantages and disadvantages, but the common theme amongst them is the need for very precise conditions that can satisfactorily apply a film coating to the oral dosage form. [1] As such, it is an inefficient type of film coating that has resulted in its lack of widespread use.
An emulsion is a mixture of two or more liquids that are normally immiscible owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working.
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are either oil-based or water-based, and each has distinct characteristics.
Polyvinylpyrrolidone (PVP), also commonly called polyvidone or povidone, is a water-soluble polymer compound made from the monomer N-vinylpyrrolidone. PVP is available in a range of molecular weights and related viscosities, and can be selected according to the desired application properties.
A tablet is a pharmaceutical oral dosage form or solid unit dosage form. Tablets may be defined as the solid unit dosage form of medication with suitable excipients. It comprises a mixture of active substances and excipients, usually in powder form, that are pressed or compacted into a solid dose. The main advantages of tablets are that they ensure a consistent dose of medicine that is easy to consume.
Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules, with useful properties. In general, it is used to incorporate food ingredients, enzymes, cells or other materials on a micro metric scale. Microencapsulation can also be used to enclose solids, liquids, or gases inside a micrometric wall made of hard or soft soluble film, in order to reduce dosing frequency and prevent the degradation of pharmaceuticals.
Electrophoretic deposition (EPD), is a term for a broad range of industrial processes which includes electrocoating, cathodic electrodeposition, anodic electrodeposition, and electrophoretic coating, or electrophoretic painting. A characteristic feature of this process is that colloidal particles suspended in a liquid medium migrate under the influence of an electric field (electrophoresis) and are deposited onto an electrode. All colloidal particles that can be used to form stable suspensions and that can carry a charge can be used in electrophoretic deposition. This includes materials such as polymers, pigments, dyes, ceramics and metals.
In materials science, the sol–gel process is a method for producing solid materials from small molecules. The method is used for the fabrication of metal oxides, especially the oxides of silicon (Si) and titanium (Ti). The process involves conversion of monomers in solution into a colloidal solution (sol) that acts as the precursor for an integrated network of either discrete particles or network polymers. Typical precursors are metal alkoxides. Sol–gel process is used to produce ceramic nanoparticles.
Powder coating is a type of coating that is applied as a free-flowing, dry powder. Unlike conventional liquid paint, which is delivered via an evaporating solvent, powder coating is typically applied electrostatically and then cured under heat or with ultraviolet light. The powder may be a thermoplastic or a thermosetting polymer. It is usually used to create a thick, tough finish that is more durable than conventional paint. Powder coating is mainly used for coating of metal objects, particularly those subject to rough use. Advancements in powder coating technology like UV-curable powder coatings allow for other materials such as plastics, composites, carbon fiber, and medium-density fibreboard (MDF) to be powder coated, as little heat or oven dwell time is required to process them.
An enteric coating is a polymer barrier applied to oral medication that prevents its dissolution or disintegration in the gastric environment. This helps by either protecting drugs from the acidity of the stomach, the stomach from the detrimental effects of the drug, or to release the drug after the stomach. Some drugs are unstable at the pH of gastric acid and need to be protected from degradation. Enteric coating is also an effective method to obtain drug targeting. Other drugs such as some anthelmintics may need to reach a high concentration in a specific part of the intestine. Enteric coating may also be used during studies as a research tool to determine drug absorption. Enteric-coated medications pertain to the "delayed action" dosage form category. Tablets, mini-tablets, pellets and granules are the most common enteric-coated dosage forms.
A blister pack is any of several types of pre-formed plastic packaging used for small consumer goods, foods, and for pharmaceuticals.
Pressure-sensitive adhesive is a type of nonreactive adhesive which forms a bond when pressure is applied to bond the adhesive with a surface. No solvent, water, or heat is needed to activate the adhesive. It is used in pressure-sensitive tapes, labels, glue dots, stickers, sticky note pads, automobile trim, and a wide variety of other products.
Pharmaceutical formulation, in pharmaceutics, is the process in which different chemical substances, including the active drug, are combined to produce a final medicinal product. The word formulation is often used in a way that includes dosage form.
Cellulose acetate phthalate (CAP), also known as cellacefate (INN) and cellulosi acetas phthalas, is a commonly used polymer phthalate in the formulation of pharmaceuticals, such as the enteric coating of tablets or capsules and for controlled release formulations. It is a cellulose polymer where about half of the hydroxyls are esterified with acetyls, a quarter are esterified with one or two carboxyls of a phthalic acid, and the remainder are unchanged. It is a hygroscopic white to off-white free-flowing powder, granules, or flakes. It is tasteless and odorless, though may have a weak odor of acetic acid. Its main use in pharmaceutics is with enteric formulations. It can be used together with other coating agents, e.g. ethyl cellulose. Cellulose acetate phthalate is commonly plasticized with diethyl phthalate, a hydrophobic compound, or triethyl citrate, a hydrophilic compound; other compatible plasticizers are various phthalates, triacetin, dibutyl tartrate, glycerol, propylene glycol, tripropionin, triacetin citrate, acetylated monoglycerides, etc.
Modified-release dosage is a mechanism that delivers a drug with a delay after its administration or for a prolonged period of time or to a specific target in the body.
Ultrasonic nozzles are a type of spray nozzle that use high frequency vibrations produced by piezoelectric transducers acting upon the nozzle tip that create capillary waves in a liquid film. Once the amplitude of the capillary waves reaches a critical height, they become too tall to support themselves and tiny droplets fall off the tip of each wave resulting in atomization.
Thin-film drug delivery uses a dissolving film or oral drug strip to administer drugs via absorption in the mouth and/or via the small intestines (enterically). A film is prepared using hydrophilic polymers that rapidly dissolves on the tongue or buccal cavity, delivering the drug to the systemic circulation via dissolution when contact with liquid is made.
Pharmaceutical manufacturing is the process of industrial-scale synthesis of pharmaceutical drugs as part of the pharmaceutical industry. The process of drug manufacturing can be broken down into a series of unit operations, such as milling, granulation, coating, tablet pressing, and others.
A nanocapsule is a nanoscale shell made from a nontoxic polymer. They are vesicular systems made of a polymeric membrane which encapsulates an inner liquid core at the nanoscale. Nanocapsules have many uses, including promising medical applications for drug delivery, food enhancement, nutraceuticals, and for self-healing materials. The benefits of encapsulation methods are for protection of these substances to protect in the adverse environment, for controlled release, and for precision targeting. Nanocapsules can potentially be used as MRI-guided nanorobots or nanobots, although challenges remain.
Nanoparticle drug delivery systems are engineered technologies that use nanoparticles for the targeted delivery and controlled release of therapeutic agents. The modern form of a drug delivery system should minimize side-effects and reduce both dosage and dosage frequency. Recently, nanoparticles have aroused attention due to their potential application for effective drug delivery.
Topical gels are a topical drug delivery dosage form commonly used in cosmetics and treatments for skin diseases because of their advantages over cream and ointment. They are formed from a mixture of gelator, solvent, active drug, and other excipients, and can be classified into organogels and hydrogels. Drug formulation and preparation methods depend on the properties of the gelators, solvents, drug and excipients used.