Creams, gel, suppositories PDF

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Creams: 

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Pharmaceutical creams are semisolid preparations that contains medicinal agents dissolved or dispersed in either water-in-oil (W/O) emulsion or an oil-in-water (O/W) emulsion (Allen, 2018). An Example of a W/O cream is cold cream and an example of an O/W cream is hydrophilic ointment. Creams have a relatively soft, spreadable consistency, and are generally described as either non-washable or washable, which reflects that an emulsion of an aqueous external continuous phase (O/W) is more easily removed than an emulsion with a non-aqueous external phase (W/O) (Allen, 2018).

Creams are formulated using a variety of oils (such as mineral and vegetable oils) and from fatty alcohols, fatty acids, and fatty esters with the solid excipients being melted at the time or preparation. Emulsifying agents in the mixture includes nonionic surfactants, detergents, and soaps.

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Initial step of preparation involves separating the components into two portions: lipid portions (all water-insoluble components) and aqueous portions (all water-soluble components). Both phases are then heated to a temperature above the melting point of the highest melting component. Both phases are then mixed, and stirred until an ambient temperature is arrived, or until the mixture has congealed. Mixing is continued during the cooling-process for uniformity. The aqueous phase is traditionally added to the lipid phase, but the reverse procedure also yields comparable results. The active pharmaceutical ingredients (APIs) is added to the phase it is soluble at the beginning of the process, or added after preparation of the cream by suitable dispersion process (such as levigation or milling).

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Clobetasol Propinate cream is a drug that belongs to the class known as topical corticosteroids.

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Clobetasol propionate is used on the skin to treat swelling, itching and irritation and can help with skin conditions such as: eczema, contact dermatitis, psoriasis, lichen planus and lupus (NHS UK, n.d).

Gels: 

Gels are semisolid systems consisting of dispersion of small or large molecules in an aqueous liquid vehicle rendered jelly-like by the addition of a gelling agent (Allen, 2018).

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Types of gelling agents used are synthetic molecules such as: Carbomer 934, cellulose derivatives (eg. carboxymethylcellulose or hydroxypropyl methylcellulose), and natural gums.

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Carbomers are high molecular weight water-soluble polymers whose viscosity depends on their polymeric composition and are used as gelling agents at concentrations of 0.5% to 2.0% in water.

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If gels contain small discrete particles they are referred to as a two-phase system. If gels do not appear to have discrete particles, they are referred to as one-phase system or single-phase system (UNC Eshelman School of Pharmacy, n.d)

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The gels are prepared by adding a gelling agent which could be natural, synthetic or semi-synthetic polymer or low molecular weight small molecules, into an organic or inorganic or aqueous solvent or solvent systems. Gels formed with large organic molecules may be formed by dispersing the molecule in the ontinuous phase, by cross-linking the dispersed molecules by changing the pH (as for cabomers), or by reducing the continuous phase (Allen, 2018). Carbomers, once fully hydrated is neutralised with Sodium hydroxide to bring the pH to 6 or greater. At this point the Carbomer turns into a Gel structure.

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An example of a medication in gel form is Clindamycin gel, a first line topical antibiotic treatment for mild acne. Clindamycin belongs to a class of medications called lincomycin antibiotics. It works by slowing or stopping the growth of bacteria that cause acne and by decreasing swelling (Medline Plus). Lincomycin kills bacteria by interfering with the ability of bacteria to produce important proteins necessary for them to survive and I effective against many types of bacteria including Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Propionibacterium acnes, and others (Ogbru, n.d).

Suppositories: 

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A suppository is a solid dosage form in which one or more APIs are dispersed in a suitable base and molded or otherwise formed into a suitable shape for insertion into the rectum to provide local or systemic effect (Allen, 2018). They are solid dosage forms intended for insertion into body orifices where they melt, soften, or dissolve and exert local or systemic effect. The shape and size must be such that it can easily be inserted into the intended orifice without causing undue distension, and must be retained for the appropriate period.

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Suppositories are prepared by two methods: molding from a melt and hand rolling & shaping. The steps in molding include: melting the base, incorporating required medications, pouring the melt into molds, allowing the melt to cool and congeal, and removing the formed suppositories from the mold. Bases used for preparation of molds include cocoa butter, glycerinated gelatin, polyethylene glycol, and most other bases are suitable. Hand rolling is the oldest and simplest method of suppository preparation and is utilized when only a few suppositories are to be prepared in a cocoa butter base (UNC Eshelman School of Pharmacy, n.d)

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INDOCID suppositories contains indometacin as the active ingredient. It belongs to a group of medicines called Non-Steroidal Anti-Inflammatory Drugs (or NSAID) (NPS Medicinewise, n.d). NSAIDs block an enzyme called cyclooxygenase (or COX) used by the body to make prostaglandins which in turn helps relieve the discomfort of fever and reduce inflammation and associated pain (Cleveland Clinic, 2020). Indomethacin is used to relieve moderate to severe pain, tenderness, swelling, and stiffness caused by osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis (MedlinePlus, 2020).

Allen, L. V. (2018). Ansel's pharmaceutical dosage forms and drug delivery systems (10th ed.) https://pharmlabs.unc.edu/labs/gels/intro.htm#:~:text=If%20the%20gel%20contains %20small,standing%20but%20liquefy%20when%20shaken. Cleveland Clinic.Org (2020). Non-steroidal Anti-inflammatory Drugs (NSAIDS). Retrieved from https://my.clevelandclinic.org/health/drugs/11086-non-steroidal-anti-inflammatorymedicines-nsaids Medline Plus (n.d). Clindamycin Topical. Retrieved from https://medlineplus.gov/druginfo/meds/a609005.html Medline Plus. (2020). Indomethacin. Retrieved from https://medlineplus.gov/druginfo/meds/a681027.html NHS.UK (n.d). Clobetasol. Retrieved from https://www.nhs.uk/medicines/clobetasol/ Ogbru, O. (n.d). (Lincocin)Lincomycin. Retrieved from https://www.medicinenet.com/lincomycin oral/article.htm#what_is_lincomycin_lincocin_what_is_lincomycin_used_for UNC Eshelman School of Pharmacy. (n.d). Gels. Retrieved from

https://pharmlabs.unc.edu/labs/gels/intro.htm#:~:text=If%20the%20gel%20contains %20small,standing%20but%20liquefy%20when%20shaken....