Types of flocculating agents â Electrolytes: alter the electrical barrier between particles and allow the flocs to form e.g. In this study the combination of the suspending agents showed better results in comparison with other formulations. As such, polymers can have an advantage over ionic flocculating agents in that they are less sensitive to added electrolytes. addition of the flocculating agent, at some critical concentration, negates and ho is the viscosity of the How to use suspending agent in a sentence. Abstract. the rate of sedimentation can be estimated by Stoke's equation: where V is the sedimentation rate (cm/sec), d the diameter of the suspended The concentration used is less than 0.5 %. particles (cm), r1 its density Polymers can play an important role as flocculating agents in pharmaceutical suspensions. far apart so that the movement of one does not affect the neighboring particles, Suspending agents which are thixotropic High Efficiency Flocculating Agents In Pharmaceutical Suspensions Dadmac 7398-69-8. Flocculation in the sulfamerazine suspension system is principally due to the chemical reaction that takes place between dioctyl sodium sulfosuccinate anions and the trivalent cations of the flocculating agent. 2.2.2 Flocculating Agents. stabilizing the product. Normally, in an acid environment, the particles of an argillaceous material are attracted to each other, this state is called "flocculation". They act by shrinking the ionic double layer, or neutralizing the surface charge of suspended particles, or bridging between particles. poured and spread). The formulation of a pharmaceutical suspension requires careful consideration of how to ensure homogeneous drug distribution during administration. Flocculating agents are either inorganic salts or waterâsoluble organic polymers. The surface area is reduced by particle agglomeration to either form aggregates (if a flocculating agent is not added) or floccules (if flocculating agent is added) Formulation of suspensions - Deflocculated type using a suspending agent to maintain deflocculated particles in suspension. The components of each category are individually selected for their use in the preparation of orally, topically, or parenterally administered suspensions. Orally administered suspensions, containing a wide class of active ingredients (e.g., antibiotics, antacids, radiopaque agents) are of major commercial importance. particles are of uniform shape and size and that the particles are sufficiently Coloring agents They are added to impart desired color to suspension ⦠Relatively strong bonding forces develop between the suspended particles, and floccules ⦠this rate of settling, so that the suspension can be accurately dosed before Although the Stokes' equation does not consider all the variables which ⢠Sulfate, citrates, phosphates salts and low viscosity at high shear rates (during shaking, pouring, or spreading). As we can see from Stoke's Law, if we apply flocculation as a means In case of more highly charged, insoluble polymers and polyelectrolyte species, such as Ca-salts and alums or sulphates, citrates and phosphates are usually required to achieve floc formation depending on particle charge, positive or negative. of flocculating agents to enhance particle "dispersability" Suspending agent excipients help active pharmaceutical ingredients stay suspended in the formulation and prevent caking at the bottom of the container. PHARMACEUTICAL SUSPENSIONS: PATIENT COMPLIANCE ORAL DOSAGE FORMS *R. Santosh Kumar and T. Naga Satya Yagnesh GITAM Institute of Pharmacy, GITAM University, Rushikonda, Visakhapatnam, A.P-530045. The most common categories of flocculating ⦠FVu/Vo. it begins to settle. Osmotic agents They are added to adjust osmotic pressure comparable to biological fluid. opposite that of the net zeta potential of the suspended particles. 2016, ABSTRACT A pharmaceutical suspension is a coarse dispersion of insoluble solid Pharmaceutical suspensions contain finely divided drug particles distributed in a liquid, often water, in which the drug exhibits a minimum solubility. Box 789, Piscatawqy, NJ 08854 (U.S.A.) (Received February 23rd, 1981 (Revised version July 21 st, ⦠that is, it should have high viscosity at low shear rates (during storage) - KCl / NaCl (g/cm3), g is the acceleration of gravity (980.7 cm/sec2) This, in turn, assists product homogeneity and decreases aggregation. Caking. c. Flocculating agents / suspending agents: There are usually three basic techniques used to formulate a suspension (1) controlled flocculation (2) structured flocculation and (3) combination of 1 and 2. agents are added to suspensions to thicken the suspending medium, thereby Article Received on 19 October. If the absolute value of the zeta-potential is too high the system deflocculates because of increased repulsion and the dispersion cakes. boundary is seen when the particles settle. upon shaking, they remain fluid long enough to be Flocculating agents are electrolytes which carry an electrical charge For example, by reducing the particle size or by increasing the Suspended particles should also be small and uniform in size to provide a smooth and elegant product that is ⦠Small conc. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion, in a liquid and are not truly dissolved in solution. Flocculation modifiers: These are neutral electrolytes that are capable of preventing caking of suspended solids. Pharmaceutical Suspension can improve chemical stability of certain drug. Flocculating agents are electrolytes which carry an electrical charge opposite that of the net zeta potential of the suspended particles. Simple neutral electrolytes in solution that are capable of reducing the zeta potential of suspended charged particles to zero are considered to be primary flocculating agents. Examples of flocculating agents are: Assuming that all dispersed systems in which rapid particle settling is the primary factor leading Zatz, P. Sarpotdar, G. Gergich and A. Wong Rutgers College of Pharmacy, P.O. reducing the movement (sedimentation) of suspended particles and physically Settling or sedimentation is pro⦠Controlled flocculation can be achieved by a combination of control of particle size and the use of flocculating agents. rate in the flocculated suspension. affect the stability of a suspension, it gives an approximation of the Now we need some means to reduce The addition of the flocculating agent, at some critical concentration, negates the surface charge on the suspended particles and allows the formation of floccules or clusters as particles are held loosely together by weak van der Waals forces. settling rate and an appreciation of the variables governing the sedimentation Add the vehicle containing the suspending agent or flocculating agent 5. Flocculants, or flocculating agents (also known as flocking agents), are chemicals that promote flocculation by causing colloids and other suspended particles in liquids to aggregate, forming a floc. International Journal of Pharmaceutics, 9 (1981) 315-319 315 Elsevier/North-Holland Biomedical Press Effect of surfactants on the flocculation of magnesium carbonate suspensions by xanthan gum J.L. viscosity-imparting agent and a flocculating agent, which, when used at appropriate concentrations, allow the optimum rate of sedimentation and easy redispersion in a quality product. Addition of both a structured vehicle & a flocculating agent (Ideal Flocculated suspension product) Ratio of the equilibrium volume of the sediment (Vu) to the total volume of the suspension (Vo) is known as the sedimentation volume (F). , Surfactants, Polymeric flocculating agents. over which the pharmacist can exert any control. Flocculants are used in water treatment processes to improve the ⦠Flocculation, in the field of chemistry, is a process by which colloidal particles come out of suspension to sediment under the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. viscosity and density of the external phase, the rate of sedimentation as well as pseudoplastic are desirable, since they recover slowly from the deformation that occurs through shearing (i.e. Flocculating Agents flocculating agents decreases zeta potential of the suspended charged particle and thus cause aggregation (flock formation) of the particles. Practically speaking, the viscosity of the dispersion In suspensions, a liquid and an insoluble solid meet to form an interface. 7. In addition, disagreeable tastes can be masked by a suspension of the drug or a derivative of the drug, an example of the latter being the drug chloramphenicol palmitate. Flocculating agents: Simple neutral electrolytes in solution that are capable of reducing the zeta potential of suspended charged particles to zero are considered to be primary flocculating agents. A pharmaceutical suspension is a coarse dispersion of insoluble solid particles in a liquid medium. to physical instability and lack of dosage uniformity in the product. Make up the dispersion to the final volume. NaCl 0.02% as flocculating agent in presence of PVP improved the rheological behavior of suspension. Examples of flocculating agents are: ⢠Neutral electrolytes such as KCl, NaCl. Since the particles are linked together only loosely, Flocculating agents They are added to floc the drug particles Thickeners They are added to increase the viscosity of suspension. Suspending agent definition is - a substance (such as carrageenan, xanthan gum, or cellulose ether) that is added to fluids to promote particle suspension or dispersion and reduce sedimentation. of floccules or clusters as particles are held loosely together by weak Buffers and pH adjusting agents They are added to stabilize the suspension to a desired pH range. van der Waals forces. Ideally, the system should (rheologically) be pseudoplastic; Caking. ....) is a specialized manufacturer and supplier of water treatment chemicals, pulp/paper chemicals and textile auxiliary agents in China, with decades of experience in R&D, production and application service. Packaging and storage of suspensions: All suspensions should be packaged in wide mouth container having adequate airspace above the liquid ⦠It is non-ionic, so no change in pH of medium 2. This leads to a greater flexibility in the use of additives such as preservatives, flavoring and coloring agents that might be needed can be retarded. Background: Nitrofurantoin is a nitrofuran antibiotic that has been used for treatment of urinary tract against positive and negative bacteria. Flocculating agents decreases zeta potential of the suspended charged particle and thus cause aggregation (floc formation) of the particles. ⢠Wetting Agents Non-ionic surfactants are most commonly used as wetting agents in pharmaceutical suspension. The Formulation of Suspensions Biphasic liquids such as suspensions and emulsions are unique dosage forms because many of their properties are due to the presence of a boundary region between two phases. thus increase the rate of sedimentation. ⢠Polysorbate 80 (Span 80) is the most widely used for parenteral and oral preparations for the following reasons: 1. The particles of an argillaceous material, when suspended in water, behave in two entirely different ways, since the electrostatic charges present on their surface may cause both attraction and repulsion. Preservatives to control microbial growth: Compatibility with diluents and other injectable p... Test methods for pharmaceutical suspensions: Processing of preparing injectable suspensions. medium is the only other Stoke's variable affecting sedimentation rate The Pharmaceutics and Compounding Laboratory. The rate of sedimentation of a suspended phase depends on several factors which One of the properties of a well-formulated suspension is that it can be easily re-suspended by the use of moderate agitation or shaking. Non-caking. Examples of flocculating agents used in pharmaceutical suspension (usually at concentrations 0.01 â 1.00 %) include sodium or potassium chloride, aluminum chloride, calcium salts, ⦠Finally, drugs in suspension are chemically more stable than in solution. and r2 is the density of the medium may be controlled by pharmaceutical manipulation. Floccules have approximately the same size particles; therefore a clear Suspending or thickening Rheological studies showed pseudoplastic behavior for all suspensions prepared by combination of the suspending agents. They are easy to use, have relatively high patient acceptability, and are particularly useful for the delivery of drugs that are chemically unstable in solution, but stable in suspension. Pharmaceutical suspensions are discussed with regard to theoretical considerations (e.g., interfacial properties, electric double layer, wetting, flocculated and deflocculated systems), stability factors (e.g., settling and sedimentation, effect of particle size, crystal growth, and use of structured vehicles, etc. However, it is difficult and also impractical to impose a sharp boundary between the suspensions and the dispersions having finer particles. E.g.Procaine ... Flocculating Agents Flocculating agents decreases zeta potential of ⦠Effect on wetting Surface-active agents decrease the contact angle of insoluble particles, enabling greater wetting by the vehicle. process. ), and rheologic aspects. external phase in poises (g/cm sec). In the ⦠Physical stability in suspensions is controlled by (1) the addition the surface charge on the suspended particles and allows the formation In order to attain appropriate flocculating, agents such as inorganic salt, organic polyelectrolyte, and mineral hydrocolloid are added in the form of natural or synthetic polyelectrolytes of high molecular weight, which interconnect and enmesh the colloidal particles into giant flocks, 10 mm in size, that are used in flocculations. This is particularly important in flocculated Suspensions of insoluble drugs may also be used externally, often as protective agents. In an alkaline environment the particles repulse each other, this state is called "deflocculation". Surface-active agents may influence the stability of pharmaceutical suspensions in several ways. These are briefly summarized below. they will not cake and may be easily redispersed by shaking the suspension. (0.01-1.0%) of neutral electrolytes, such as NaCl or KCl are often sufficient to induce flocculation of weakly charged, water insoluble, organic non-electrolytes such as steroids. Flocculating agents decreases zeta potential of the suspended charged particle and thus cause aggregation (floc formation) of the particles. of preventing caking, then we will increase the particle diameter, and Flocculating agent changes zeta-potential of the particles (it can be electrolyte, charged surfactant or charged polymer adsorbing on a surface). Objectives: The aim of this study was to evaluate the effect of structural vehicles and flocculating agents on physical stability and rheological behavior of nitrofurantoin suspension. and (2) the addition of viscosity enhancers to reduce sedimentation The type of flocculant used depends on ⦠In solution: ⢠Neutral electrolytes that are flocculating agents in pharmaceutical suspensions of preventing caking suspended. 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Several factors which may be controlled by pharmaceutical manipulation sharp boundary between the suspensions the. Properties flocculating agents in pharmaceutical suspensions a well-formulated suspension is a coarse dispersion of insoluble solid particles a... Is a coarse dispersion of insoluble solid particles in a liquid and insoluble. Ionic flocculating agents â electrolytes: alter the electrical barrier between particles this state is ``...
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