Semi solids ppt
- 1. SEMI – SOLIDS Shekinah Faith S. Balindan BSPharmacy 4B
- 2. Learning Objectives • Uses • Factors Influencing Absorption • Raw Materials For Semisolids • Type Of Vehicle • Factors Which Influence The Choice Of Semisolid Vehicles • Classes Of Semisolid – Usp • Ophthalmic Ointment • Preparation Of Ointment • Semisolids • Manufacture Of Emulsified Semisolid
- 3. Pharmaceutical dosage form with viscous consistency intended for application on the skin
- 4. - Vehicle for topically applied drugs - Emollients-soothing or softening's effect on surface tissue - Protective or occlusive dressings on the skin
- 5. - Partition coefficient of the drug - Moisture and temperature in the environment of the skin - Pathologic injury to the skin Vehicle used
- 6. PARTITION COEFFICIENT Substance processing both water and lipid solubility are favorable absorbed through the skin
- 7. MOISTURE AND TEMPERATURE - The moisture balance on the stratum corneum (horny layer of the epidermis) of the skin has been due to the presence of a combination of compounds known as “natural moisturizing factor”.
- 8. MOISTURE AND TEMPERATURE - The fat in the skin provides a protective film to prevent this factor from being removed from the skin during excessive contact with water as a bathing
- 9. PATHOLOGIC INJURY TO THE SKIN - Skin penetration has been enhanced by abrasions or stripping the skin of its barrier layer - Skin penetration of the drug substances can be the use of suitable vehicles
- 10. HYDROCARBONS Petrolatum and mineral oil are perhaps the widely used substance in semisolids next to water Petrolatum – a complex mixture of semisolids containing hydrocarbon alipathic, cyclic, saturated, unsaturated branch and unbranched substance in varying proportions Mineral oil – obtained from petroleum acid. Lower viscosity is more preferred since it is less tacky.
- 11. HYDROCARON WAXES Employed to increase the viscosity of mineral oil to prevent separation from ointment. Paraffin and ceresin wax
- 12. OLEAGINOUS SUBSTANCES Vegetable oil such as peanut, almond oil, almond oil, sesame oil and olive oil and glycerides of mixtures of unsaturated fatty acids
- 13. FATTY ACIDS AND ALCOHOLS Stearic acids – used in water removable creams as an emulsifier to develop a certain consistency in the cream Stearyl alcohol and cetyl alcohol (palmityl alcohol) – used in creams as auxiliary emulsifiers and emollients; in sufficient stearyl alcohol produces a firm cream which maybe softened by cetyl alcohol.
- 14. EMULSIFIERS - The water soluble soaps (triethanolamine stearate soap) were among the first emulsifiers used for semisolid oil in water emulsions. The viscosity of the cream or emollient prevents coalescence of the emulsified phases and helps to stabilize the emulsion. The interfacial film formed around the dispersed phase globules is generally solid making emulsified preparation more rigid.
- 15. POLYOLS Glycerin, propylene glycol, sorbitol 70% and the lower molecular weight polyethylene glycols are used as humectants (prevent drying up) and prevent formation of crust on the top of the cream
- 16. INSOLUBLE POWDERS Insoluble powders must be uniformly dispersed throughout the vehicle to assure homogeneity of the product. The solid must be impalpable to touch. Particles less than 74 microns in size equivalent to the mesh openings in a number 200 mesh sieve of the US standard sieve series are considered impalpable to most people
- 17. - The vehicle used for semisolid pharmaceutical preparation differs from that used for cosmetics because with a cosmetic, penetration to the skin is not desired. - A well formulated pharmaceutical semisolid should be both effective therapeutically and cosmetically appealing but in major effort must be in medicinal direction
- 18. - Nature of the skin lesion - Solubility and stability of the drug
- 19. Hydrocarbon base Adsorption base Water removable base Water soluble base
- 20. HYDROCARBON BASE Petrolatum and white ointment (petrolatum with 5% beeswax) are typical lipophilic vehicles Petrolatum is the most commonly used in ointment vehicles because of its consistency, bland and neutral characteristics and its ability to spread easily on the skin These vehicle is difficult to wash off and are used as occlusive dressings which produces sensation of warmth because of the normal evaporation of perspiration is inhibited
- 21. ABSORPTION BASES Hydrophilic mixtures formed by the addition of substances miscible with hydrocarbons and possessing polar groupings such as SO4, sulfonate, carboxyl, hydroxyl or an ether linage. E.g. lanolin, cholesterol, sterols, sorbitan monostearate, sorbitan monooleate
- 22. ABSORPTION BASES - Mineral oil is added to these bases to reduce tackiness of the base - Cold cream type w/o emulsion belongs to this type of the base. This is a borax-beeswax combination with mineral oil or vegetable oil as the continuous phase. A protective oil film remains on the skin and slow evaporation of water gives the skin a cooling effect.
- 23. WATER REMOVABLE BASE - They are oil in water emulsions - Upon application and rubbing into the skin, there is little or no visible evidence of its presence - The vanishing cream - o/w emulsion but with absorption base which is w/o emulsion
- 24. WATER SOLUBLE BASE - Prepared from mixtures of high and low molecular weight polyethylene glycols - Characteristics: • Low molecular weight are liquids; moderately higher molecular are unctuous, high molecular weight are solids • No water is required for their preparation • Combination of high and low molecular weight polyethylene glycols yield products having ointment like consistency which softens or melts when applied to the skin • Have polar group • Also known as greaseless ointment base
- 25. - Semisolid ophthalmic vehicles frequently contain soft petrolatum, a brand adsorption base or water soluble base - Material used should avoid the eye discomfort and irritation - Should be sterile when used in injure eye
- 26. Fusion method (anhydrous ointments) – dissolving the active ingredients in the melted fats and waxes or in the vehicle and then mixed with the base. • Melted mass must be mixed while cooling to ensure homogenous distribution of the ingredients
- 27. PRESERVATION Preservation is evaluated to: - Stability with regard to other components of the formula - Container to be used
- 28. CHARACTERISTICS OF PRESERVATIVES • Some preservatives becomes inactive in the presence of other ingredients - 5% tween 80 in activates 80% of the total methyl paraben – higher conc. of preservatives is required • Boric acid may be used in ophthalmic preparation
- 29. ANTIOXIDANTS -Added whenever oxidative deterioration is anticipated. -Choice of antioxidants depends on: Toxicity Irritating potency Compatibility Odor Discoloration Solubility Stability
- 30. Aeration should be prevented for stability and consistency in density. This can be done by introducing one phase below the surface of the other liquid or phase and mixing carefully In filling into tubes, the hopper should be filled with the product to prevent incorporation of air
- 31. RHEOLOGICAL CHANGES Rheology – study of deformation and flow property of liquid and semisolid; when subjected to stress (homogenization) tend to deform in shape and flow Rheological changes in semisolid increases the consistency due to increase of the number of emulsified droplets but may decrease viscosity due to electrolyte effect Consistency is also affected by the number of times the preparation is passed through a homogenizer
- 32. 3 factors to be controlled during manufacturing: Time of mixing Temperature Mechanical works including rate of agitation Equipment should be automatically controlled as to regulation on temperature by jacket around tank. Regulation of mixing time and rate of agitation
- 33. STEPS IN MANUFACTURING Preparation of oil and aqueous phase Mixing of phases Cooling of semisolid emulsions Homogenization Storage while awaiting test Transfer of material for packaging
Editor's Notes
- #4: A semisolid thing is something that is not really a solid or a liquid. Mayonnaise is an example. Mayonnaise does not hold its shape like a solid but does not flow like a liquid. Normally semisolids are covalent things. Covalent substances get softer and softer until they melt.