Rectal ointments

The use of rectal ointments is generally limited to the treatment of local conditions. Rectal solutions are employed as enemas or cleansing solutions. 

Oxypolyethoxydodecane, a derivative of alkyl polyethylene used as antipruritic agent in Anacal rectal ointment, caused perianal allergic contact dermatitis in a woman (Calnan 1978). 

The inclusion of the a routine microbial limit test in a marketed product stability protocol depends on the pharmaceutical dosage form. Typically, the test would be used only for nonsterile products, especially oral liquids, nasal sprays, and topical liquids, lotions, and creams that have sufficient water activity to support the growth of microorganisms. In contrast, tablets, powder- and liquid-filled capsules, topical ointments, vaginal and rectal suppositories, nonaqueous liquids and inhalation aerosols with a water activity too low to allow for the product to support the growth of microorganisms would not be routinely tested. 

Rectal Avoids problems of stability in gastrointestinal tract No first-pass metabolism Useful if oral administration is not possible Unpopular Inconvenient Erratic absorption Irritation Suppositories, enemas (solutions, suspensions, emulsions), foams, ointments, creams... 

Orifices. Include eye, ear, nose, throat, rectal, vaginal, and the mouth as a route to the throat and lungs, orifices using suppositories, pessaries, drops, solutions, ointments, gases, vapors, aerosols, and inhalations. 

Topical dosage forms such as creams, emulsions, gels, lotions, ointments, pastes, and powders may be marketed in plastic materials. Topical dosage formulations are for local (not systemic) effect and are generally applied to the skin or oral mucosal surfaces. Some vaginal and rectal creams and nasal, otic, and ophthalmic solutions may be considered for topical drug products. 

A 62-year-old woman, who had applied DoloPosterine N ointment topically to the perianal skin and rectal mucosa for several days, developed erythematous vesicular lesions in the perianal area and an erythematous edematous rash of the face, axillae, elbow flexures, and inner thighs (7). This abated on withdrawal of the drug and the administration of oral prednisolone for 10 days. Patch testing was positive with cinchocaine. 

Included in the FDA Inactive Ingredients Guide (ophthalmic preparations, oral capsules and tablets, otic and rectal preparations, topical aerosols, creams, emulsions, ointments and solutions, and vaginal preparations). Included in nonpar-enteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients. 

In cosmetics and topical pharmaceutical preparations, medium-chain triglycerides are used as a component of ointments, creams, and liquid emulsions. In rectal formulations, medium-chain triglycerides have been used in the preparation of suppositories containing labile materials. 

Sesame oil may be used as a solvent in the preparation of subcutaneous injections, oral capsules, rectal suppositories, and ophthalmic preparations it may also be used in the formulation of suspensions and emulsions. Multiple-emulsion formulations, in which sesame oil was one of the oil phases incorporated, have been investigated as a prolonged-release system for rifampicin microemulsions containing sesame oil have been prepared for the transdermal delivery of ketoprofen. Sesame oil has also been used in the preparation of liniments, pastes, ointments, and soaps. A sesame paste... 

There are two main ways by which substances may be administered to humans the enteral and the parenteral routes. For enteral administration the substance is placed directly into the gastrointestinal tract by permitting a tablet to dissolve when it is placed under the tongue (sub-lingual administration), or by swallowing a tablet, capsule or a solution (oral) or by rectal administration as a suppository. In parenteral administration the substance in solution may be injected subcutaneously, intramuscularly or intravascularly, inhaled as an aerosol, applied topically to the skin as a cream or ointment, or, rarely, in the form of a pessary. 

Dibucaine (No. 11) is probably the most toxic anesthetic presently in use, as it is 15 times more toxic than procaine. It is also about 15 times more potent thus it is usable at low doses. Parenteral use is limited to the spinal route effects are long lasting (see Table 13-6). This property makes it particularly appealing for topical use (skin) and mucocutaneous areas (e.g., rectal) in the form of creams and ointments. 

Drugs are administered rectally either for their local, or less frequendy, for their systemic effects. The dosage forms given rectally include solutions, suspensions, suppositories, and ointments. 

Clearly, the formulation chosen for particular drugs is not random. Furthermore, the degree to which it is critical varies from drug to drug. For example, hydrocortisone is available for at least seven routes of administration, as tablets, several creams and ointments, intraocular solutions, suppositories, intra-rectal foams, injections, and eardrops. Even newer drugs, with fewer indications than hydrocortisone, seek greater market acceptability by providing a variety of alternative formulations (e.g. sumatriptan is available as an injection, intranasal spray, suppository, and tablets). 

Use Level 0.4% (suspending agent), 0.5-5% (aq. ointment base) Regulatory FDA approved for orals, rectals, topicals BP, EPcompliance Manuf./Distrib. Adept Sol ns. Aldrich Cornelius Chem. Co. Ltd GoldschmidtAG Noveon Protameen R.I.T.A. Sigma Spectmm Quality Prods. 

SemisoUd rectal preparations (ointments, creams and gels)... 

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. 

Condoms become permeable in contact with a cream or ointment base containing fats or paraffin [62]. This may be a problem for rectal as well as vaginal use. The same problem applies to occlusive diaphragms. For these reasons, a hydrophilic gel is the best possible base if combination with condoms or diaphragms cannot be excluded. An example of a hydrophilic gel is the vaginal gel pH 5 (Table 11.17), used as lubricant in case of vaginal dryness. 

---