Ointment dosage forms preparation

Ophthalmic Dosage Forms. Ophthalmic preparations can be solutions, eg, eye drops, eyewashes, ointments, or aqueous suspensions (30). They must be sterile and any suspended dmg particles must be of a very fine particle size. Solutions must be particle free and isotonic with tears. Thus, the osmotic pressure must equal that of normal saline (0.9% sodium chloride) solution. Hypotonic solutions are adjusted to be isotonic by addition of calculated amounts of tonicity adjusters, eg, sodium chloride, boric acid, or sodium nitrate. 

Amongst the various types of semisolid preparations, ointments represent the type of extemporaneous preparations most likely to be prepared by a pharmacist. A variety of ingredients may be included in the formula of semisolid dosage forms. 

Pharmaceutical products can be classified as liquid solutions, disperse systems (e.g., emulsions, suspensions), semisolids (e.g., ointments), and solid dosage forms. Liquid solutions are homogeneous mixtures of one or more substances in pharmaceutical liquids. The understanding of the physicochemical properties of liquid solutions and processes to prepare the liquid solutions is an important step in preparing final liquid solution dosage forms. In this chapter, the solutions of gases in liquids, liquids in liquids, and solids in liquids, as well as colligative properties of solutions and their application to pharmacy, are discussed. Disperse systems will be discussed in Chapter 4. 

Liniments Liniments are external preparations of a consistency thicker than water, but thinner than ointments, usually applied to the skin with a gentle rubbing of the hands. Liniments are among the oldest of dosage forms, along with related forms, such as plasters and ointments. The term came to its present use about 1600. Drying liniments are preparations which dry when smeared on the skin, forming a medicated film removable by water. 

Additional multiple-unit containers are in widespread use such as collapsible tubes, metered-dose inhalers, and aerosol containers. The f/j / /AF provides standards for aerosols and containers used for aerosols in Aerosols, Metered-Dose Inhalers, and Dry Powder Inhalers (601) and Pharmaceutical Dosage Forms (1151). Commonly used for ointments and pastes, the collapsible tube container is often constructed of plastic, metal, or some lamination of plastic and metallic layers. Although such preparations can be packaged in jars or bottles, collapsible tubes can offer better protection from contamination and from environmental hazards. The metered-dose inhaler and aerosol container are other specific multiple-unit dosage form examples that are commonly fabricated from metal and are closely tied to the process of medication administration. " ... 

Waxes have been used by the pharmaceutical industry for many years. Their applications in semisolid preparations, including ointments, creams, or lotions, and in suppositories are well known and numerous publications exist on this topic. Because of their lipophilic properties, waxes have been used in sustained-release single or multiple unit solid dosage forms. This article reviews the different uses of waxes as sustained-release carrier or coating materials. 

Factors affecting the release of drugs from other dosage forms can usefully be examined. These include suppositories, topical ointment and cream preparations, and transdermal devices. 

There are a number of attributes of topical drug systems that may be classified as cosmetic that make patients more or less whHng to use their medications (comphant). These include the ease of appHcation, the feel of the preparation once it is on the skin, and the appearance of the applied film. Ideally, the appHcation should be undetectable to the eye and neither tacky nor greasy. Certain items, such as ointments and pastes, are of course intrinsically greasy, and suspensions of aU types tend to leave an opaque, easily detectable fHm. Thus, the extent to which the cosmetic features can be idealized is dependent on the nature and purpose of the dosage form. 

Semisolid Dosage Forms [SUPAC-SS] — Semisolid dosage forms include nonsterile and semisolid preparations, for example, creams, gels, and ointments, intended for all topical routes of administration. 

Locai anesthetic agents generaiiy are prepared in various dosage forms aqueous solutions for parenterai injection, and creams and ointments for topicai appiications. Thus, chemical stability and aqueous soiubiiity become primary factors in the preparations of suitable pharmaceutical dosage forms. 

In this chapter several aspects of ocular dosage forms are discussed with emphasis on eye drops, eye lotions and eye ointments prepared in pharmacies. Their formulation, method of preparation, packaging, storage and methods of administration are also discussed. 

To improve the therapeutic effect of a medicine, one should try to increase the absorption of the active substance. Eye ointments and eye creams stay much longer in the conjunctival sac and on the ocular surface than eye drops. Consequently the active substance is delivered during a longer period of time to the eye. Ointments or creams could be considered as prolonged release dosage forms (depot preparations) for ophthalmic use. Viscous eye drops can... 

According to national legislation the label mentions the dosage form (eye cream or eye ointment), the route of administration (ocular use), the intended use, the storage conditions, the expiry date and, for multidose containers, the beyond-use date after which the opened preparation must not be used. This period should not exceed 4 weeks. If necessary the label also bears warnings and mentions that the contents should be brought to room temperature before administration if the tube is stored in the refrigerator. 

Vaginal foams Medicated vaginal tampons From the rectal dosage forms the suppositories, enemas, ointments and creams are important as extemporaneous pharmacy preparations from the vaginal dosage forms fliese are the vaginal suppositories (pessaries), solutions, creams and gels. 

For rectal application ointments and creams are common, for vaginal application creams and gels are used. They act locally and the design and preparation hardly differ from corresponding dosage forms for cutaneous use. In the subsequent sections some aspects of semisolid preparations for rectal and vaginal use will be discussed that are not encotmtered in cutaneous use. 

The ocular administration of medicines is only used for a local effect in, on or around the eye. The local application results in high local concentrations of the active substance. Pharmaceutical dosage forms for the eye encompass eye drops, eye washings, eye ointments, inserts and intra-ocular injections. In all cases, it is important that the preparations do not cause irritation of the eye. If they do, the medicine will be washed out quickly due to tear production, which may reduce the effect and limit its duration. In additimi, small sharp particles can damage the eye. Strict limits exist for pH and tonicity of ocular preparations. 

The dispersion of a solid into a Uquid can be found in dosage forms such as mixtures, dermatologic preparations, suppositories, enemas, and eye drops. Qiaracteristic for this process is the requirement of energy to obtain a homogeneous mixture furthermore, often separation occurs upon storage. This does not apply for suppositories, ointments or creams, which during the preparation are a dispersion of a solid into a liquid, but, once soUdiUed, form a semisoUd dispersion. 

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