Semi Solid Preparations
Session 5: Semi Solid Preparations
Total Session Time: 120 Minutes
Prerequisites
Learning Tasks
By the end of this session students are expected to be able to:
Define semi – solid pharmaceutical preparations
List ideal properties of semi – solid preparations
Explain rational approaches to topical formulation
List treatment target for semisolid preparations
Explain components of semi – solid pharmaceutical preparations
Resources Needed:
SESSION OVERVIEW
Activity/
Step Time Content
Method
1 05 Minutes Presentation Introduction, Learning Tasks
10 Minutes Presentation Definition of Semi- Solid Pharmaceutical
2
Buzzing Preparations
3 15 Minutes Presentation Ideal Properties of Semi – Solid Preparations
4 15 Minutes Presentation Rational Approaches to Topical formulation
35 Minutes Presentation
5 Treatment Target for Semisolid Preparations
Brainstorming
30 Minutes Presentation Components of Semi – Solid Pharmaceutical
6
Preparations
7 05 Minutes Presentation Key Points
8 05 Minutes Presentation Evaluation
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SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing.
STEP 2: Definition of Semi – Solid Preparations (10 minutes)
Activity: Buzzing (5 minutes)
ASK students to pair up and buzz on the following question for 2 minutes
ALLOW few pairs to respond and let other pairs to add on points not mentioned
WRITE their response on the flip chart/board
CLARIFY and SUMMARIZE by using the content below
the skin or accessible mucous membranes to provide localized and sometimes systemic effects at
the site of application, it is a preparations designed to exert local activity when applied to the
skin or mucous membranes
emollient, and therapeutic agents, these semi-solid pharmaceutical preparations for external
application are: ointments, pastes, creams, poultices/cataplasms and gels.
STEP 3: Ideal Properties of Semi – Solid Preparations (15 minutes)
o Smooth texture
o Elegant in appearance
o Non dehydrating
o Non gritty
o Non greasy and non-staining
o Non hygroscopic
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o Non irritating
o Do not alter membrane / skin functioning
o Miscible with skin secretion
o Have low sensitization index
o Easily applicable with efficient drug release.
o High aqueous washability.
o Should be stored at temperatures not exceeding 25°c unless otherwise authorized.
o They should not be allowed to freeze and must be stored in a well-closed container or, if the
preparation contains water or other volatile ingredients, store in an airtight container.
o The containers are preferably collapsible metal tubes from which the preparation may be
readily extruded.
o If the preparation is sterile, store in a sterile, airtight, tamper-proof container.
STEP 4: Rational Approaches to Topical Formulation (15 minutes)
o By manipulating barrier function of skin;
Topical antibiotics and antibacterials help damaged barrier to avoid infections
Sunscreen and the horny layer protect viable tissues from u.v. radiations
Emollients restore pliability to desiccated horny layer
o By directing drugs to the viable skin tissues without using oral, systemic or other routes of
therapy
o By using skin delivery for systemic treatment
e.g. transdermal therapeutic systems provide systemic therapy for motion sickness,
angina and hypertension
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STEP 5: Treatment Target for Semi – Solid Preparations (35 minutes)
Activity: Brainstorming (15 minutes)
Ask students to brainstorm on the following question:
ALLOW few students to respond
WRITE their responses on the flip chart/ board
CLARIFY and SUMMARISE by using the content below
o Skin surface, horny layer, viable epidermis and upper dermis, skin glands, and systemic
circulation.
o Care for skin surface is mainly by cosmetic application, that form protective layer, or attack
bacteria and fungi
o Sunscreens, barriers that hinder moisture loss, antimicrobials and insect repellants)
o Main therapies aimed at the horny layer improve emolliency by raising water content or
stimulating sloughing
o E.g. keratosis, exfolients such as salicylic acid
o Antiperspirants (aluminium) reduce hyperhidrosis of sweat glands
o Exfolients (e.g. salicylic acid, tretinoin (retinoic acid), benzoyl peroxide) for acne
o Topical antimicrobials, depilatories etc.
o Diseases can be treated provided that the preparation efficiently delivers drug to the receptor
fluorouracil) anesthetics (e.g. benzocaine), antihistamines
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o In recent years considerable scientific work has led to the skin route being used to treat several
conditions by means of transdermal patches
o E.g. motion sickness (hyoscine), angina (nitroglycerin)
STEP 6: Components of Semi – Solid Pharmaceutical Preparations (30 minutes)
o Prevents or slows oxidation of other components
o Examples: Tocopherol, butylated hydroxy toluene, or a reducing agent such as ascorbic acid.
o Major classes or types of formulation compositions based on composition and physical
properties.
o Examples: Please refer to bases chapter.
o Acid-conjugate base mixture employed to control pH and therefore control ionization state of
drug and impart stability
o Examples: Citrate, phosphate, tartarate
o Have the ability to bind metal ions; prevents auto-oxidation phenomena frequently catalyzed
by metal ions and enhances action of preservatives by binding iron and copper ions essential
to microbial growth.
o Example: EDTA, citric acid
of individual phases.
o Example: Detergent, emulsifying wax (detergent treated wax), cetostearyl alcohol,
polysorbate 20.
glycols (low MW).
corneum by chemical modification.
o Example: Ethanol, oleic acid, propylene glycol, polyethylene glycol (400)
o Prevents or slows microbial growth; may be one of 4 major compound types: acid, alcohol,
quaternary ammonium compounds, or organic mercurial.
o Example: Acid: benzoic acid; alcohol: phenylethyl alcohol; quaternary ammonium: stearyl
dimethyl benzyl ammonium chloride; organic mercurial: thimerosal.
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o Example: Natural: cellulose, pectin; semi-synthetic: methylcellulose, (sodium)
carboxymethylcellulose; synthetic: Carbopol
STEP 7: Key Points (5 minutes)
or accessible mucous membranes to provide localized and sometimes systemic effects at the site
of application, it is a preparations designed to exert local activity when applied to the skin or
mucous membranes
application properties and storage properties
STEP 8: Evaluation (5 minutes)
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References
Britain, R. P. S. o. G. (1994). The Pharmaceutical Codex (12 ed.). London: London Pharmaceutical
Press.
Winfield, J. A. R., I. Smith. (2009). Pharmaceutical Practice (4th ed.)British
Wolverton, SE. Comprehensive Dermatologic Drug Therapy. WB Saunders. 2001. pp 563-572.New
York
Singh Malik, D; Mital, N; Kaur, G (2016). "Topical drug delivery systems: a patent review". Expert
opinion on therapeutic patents. 26 (2): 213–28. Sudan
Senya, S. S., Mwasha, C. Y. S., Muyinga, A. M., Amiri, R. I., & Mauga, E. A. S. K. (2011). Tanzania
Pharmaceutical Handbook (2nd ed.). Dar es salaam.
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