COLLEGE OF PHARMACY PHARMACEUTICS II (PHT 312) Dr. Mohammad Javed Ansari, PhD. Contact info: javedpharma@gmail.com DEPARTMENT OF PHARMACEUTICS, COP, SAU, AL-KHARJ, KSA Monday, December 01, 2014
OBJECTIVES OF THE LECTURE At the end of this lecture, you will be able to explain: What are sweet / viscous solutions? What are various types of sweet / viscous solutions.? What are various types of syrups? What are various sources of syrups? What are advantages of syrups? What are disadvantages of syrups? How syrups are prepared?
Viscous liquids Syrups, Honeys, Mucilages, and Jellies are viscous liquids or semisolids. The sweetness and viscid appearance are given by sugars, polyols, or polysaccharides (gums). SYRUPS Syrups are concentrated solutions of sugar such as sucrose in water or other aqueous liquid. Simple syrup: when water is used alone for making syrup. Medicated syrup: Syrup with some medicinal substance. Flavored syrup: Syrup with some aromatic or pleasantly flavored substances and is intended to be 3 used as a vehicle or flavor for prescriptions
SYRUPS Simple sucrose syrup is (85% w/v). In dilute solutions sucrose provides an excellent nutrient for molds, yeasts, and other microorganisms. A saturated solution may lead to crystallization of a part of the sucrose under conditions of changing temperature. High density & specific gravity (s.g. =1.313). High viscosity Preservation (hypertonic solution) 4
Therapeutic Syrups / Medicated Syrups Therapeutic agents /API may either be directly incorporated into simple syrups or may be added as the syrup is being prepared. It should also be remembered that the choice of syrup vehicle must be performed with due consideration to the physicochemical properties of the therapeutic agent /API. For example, cherry syrup and orange syrup are acidic in nature and therefore the solubility of acidic therapeutic agents may be lowered and may result in precipitation of the drug substance. This may also reduce chemical stability of acid-labile therapeutic agents, leading to reduced stability and shelf life. Hence it is very important to ensure that the therapeutic agent is soluble and stable within the syrup base. 5
Advantages of Syrups Due to sweetness, can mask the taste of salty and bitter drugs and therefore serve as pleasant tasting vehicle. Used as vehicle for pediatric use due to their high viscosity and the smoothness and mouth feel qualities. Enhance the flavour Due to the wide variety of flavors of syrups such as orange, lemon, peppermint, these are widely acceptable. Disadvantages: Carmelization (dehydrated and polymerized sugar). Crystallization (precipitation) Microbial attack (infection/degradation) Cap locking (handling issues) Diabetogenic (therapeutics issues) 6
(a) Solution with heat Preparation of Simple Syrup The sucrose is added to the purified water or aqueous solution and heated until dissolved Heat stable components are added to the hot syrup If other components are heat labile, they are added after cooling like alcohol and oil. Advantages: make the syrup rapidly. Disadvantages: Not suitable for volatile substances or those injured by heat. Inversion of sucrose causing discoloration of syrups due to caramelization. Examples : Acacia syrup, NF; Cocoa Syrup, NF; Syrup USP. 7
Preparation of Simple Syrup (b) Agitation without Heat This process is used in those cases where heat would cause loss of valuable volatile constituents. The syrup is prepared by adding sucrose to the aqueous solution in a bottle of about twice the size required for the syrup. This permits active agitation and rapid solution. The stoppering of the bottle is important, as it prevents contamination and loss during the process. Advantages: No inversion of sucrose /no discoloration of syrups. Examples: Ephedrine Sulfate and Citric acid Syrup. 8
(C) Percolation: Preparation of Simple Syrup Purified water or an aqueous solution is permitted to pass slowly through a bed of crystalline sucrose, thus dissolving it and forming a syrup. A pledge of cotton (B) is placed in the neck of the percolator. The percolate (A) is collected and returned to the percolator as required until all of the sucrose has been dissolved. Example: Tolu Balsam syrup Ipecac Syrup 9
Alternative sources of Syrups 1. Non reducing sugars like DEXTROSE 2. Non-sugar polyols (sorbitol, glycerin, propylene glycol, mannitol), 3. Non-nutritive artificial sweeteners (aspartame, saccharin) Dextrose: Can be used in syrups containing strong acids in order to eliminate the discoloration associated with caramelization. Dextrose is less sweet. Dextrose dissolves more slowly. Forms a saturated solutions in water at 70%w/v which is less viscous than simple syrup. Saturated solution supports growth of microorganism and therefore more easily fermented. Addition of sweetener, thickener and preservative is must. 10
Alternative sources of Syrups Non-sugar polyols (sorbitol, mannitol, glycerin, propylene glycol): These excipients provide favorable viscosity, reduce cap-locking and have preservative & solvent actions also. Therefore these may be added to retard crystallization of sucrose or increase the solubility of added ingredients. Sorbitol, A hexahydric alcohol, C 6 H 14 O 6, made by hydrogenation of glucose is used mostly in the 70% aqueous solution USP trademark Sorbo Sorbitol is chemically stable and practically inert. Many drugs are more stable in sorbitol than in sucrose solution thus may have extended shelf-life. Although it is 60% as sweet as sucrose and half as viscous as simple syrup, it has excellent mouth feel and lacks acrid characteristics. Unlike sucrose, it does not contribute to the formation of dental caries. Although it is metabolized and converted into glucose it is not absorbed from the GIT as rapid as sugars, so no significant hyperglycemia is formed. Sorbitol inhibits the sticking and locking of bottle caps which occurs with high concentration of sucrose so they are usually combined. 11
Alternative sources of Syrups Artificial Syrups (Non-Nutritive Syrups) For diabetic patients who must regulate their sugar and/or calorie intake accurately. Eg. Diabetic Simple Syrup, contains compound sodium cyclamate (6% cyclamate sodium and 0.6% saccharin sodium). Saccharin sodium is 300-550 time as sweet as sucrose. characterized by a bitter after taste / metallic taste. Studies showed that the cyclamate and saccharin sodium could produce cancer in animals. Artificial sweeteners do not impart the characteristic viscosity of syrups and therefore require the addition of viscosity modifires, such as methylcellulose. Aspartame, methyl ester di-peptide of aspartic acid and phenylalanine (about 200 times sweeter than sucrose) is being 12 used as the safe sweetening agent.
Preservation of Syrups High concentration of sucrose (85% v/v) and associated unavailability of water (termed low water activity) in simple syrup USP, ensures that the addition of preservatives is not required. Syrups USP, being hypertonic solutions, act as bactericidal and hence are protected from bacterial contamination. Dilute syrups are good media for microbial growth and require the addition of preservatives, such as methyl paraben, propyl paraben, benzoic acid and sodium benzoate in a concentration range of 0.1 0.2% w/v. Glycerin (30% v/v) may be used as preservative. It will also serve as co-solvent and reduce sucrose crystallization. The official syrups should be preserved in well dried bottles and stored in a cool dark place. The USP suggests that syrups be kept at a temperature not above 13 25 C.
HONEYS Are thick liquid preparations. At one time, before sugar was available, honey was used as a base, instead of syrup. Honey is the secretion deposited in the honeycomb of the bee and consists of a mixture of invert sugar 62-83%; sucrose 8%; dextrin 0.2% There are few official preparations containing honey. e.g. Oxymel, or" acid honey "'is a mixture of acetic acid, water and honey. 14
MUCILAGES The official mucilages are thick viscid, adhesive liquids, produced by dispersing gums (gum acacia or gum tragacanth) in water. Mucilages are used as suspending agents for insoluble substances in liquids; their colloidal character and viscosity prevent immediate sedimentation. Acacia Mucilage NF, Tragacanth Mucilage NF Place the gum in wide mouth graduated bottle, add sufficient quantity of purified water, stopper and lay the bottle, rotate occasionally, and when gum has been dissolved, strain through muslin cloth. Uses: Demulcent, suspending agent, excipient in making pills as emulsifying agent for cod liver oil and as protective agent. Synthetic agents e.g. carboxymethylcellulose (CMC) or polyvinyl alcohol are non-glycogenetic and may be used for diabetic patients. 15
JELLYS Preparations having a jel-like consistency. Usually made mostly from the juices of various fruits with the help of gelling agents like gelatin, carrageenan, and pectin. Apple, grape juice and pectin-containing jellyy such as Certo, have become popular home remedies for those seeking arthritis pain. Jellys are used as lubricants for surgical gloves and catheters. Lidocaine HCl Jelly USP is used as a topical anesthetic. 16
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