....) 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. 2016, ABSTRACT A pharmaceutical suspension is a coarse dispersion of insoluble solid Abstract. of preventing caking, then we will increase the particle diameter, and Relatively strong bonding forces develop between the suspended particles, and floccules … The rate of sedimentation of a suspended phase depends on several factors which In the … boundary is seen when the particles settle. High Efficiency Flocculating Agents In Pharmaceutical Suspensions Dadmac 7398-69-8. Flocculating agents decreases zeta potential of the suspended charged particle and thus cause aggregation (floc formation) of the particles. These are briefly summarized below. may be controlled by pharmaceutical manipulation. 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. and (2) the addition of viscosity enhancers to reduce sedimentation Add the vehicle containing the suspending agent or flocculating agent 5. This is particularly important in flocculated Non-caking. Orally administered suspensions, containing a wide class of active ingredients (e.g., antibiotics, antacids, radiopaque agents) are of major commercial importance. They act by shrinking the ionic double layer, or neutralizing the surface charge of suspended particles, or bridging between particles. Small conc. It is non-ionic, so no change in pH of medium 2. The most common categories of flocculating … How to use suspending agent in a sentence. 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. agents are added to suspensions to thicken the suspending medium, thereby external phase in poises (g/cm sec). As we can see from Stoke's Law, if we apply flocculation as a means (g/cm3), g is the acceleration of gravity (980.7 cm/sec2) Assuming that all dispersed 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. This leads to a greater flexibility in the use of additives such as preservatives, flavoring and coloring agents that might be needed However, it is difficult and also impractical to impose a sharp boundary between the suspensions and the dispersions having finer particles. 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. opposite that of the net zeta potential of the suspended particles. • Polysorbate 80 (Span 80) is the most widely used for parenteral and oral preparations for the following reasons: 1. thus increase the rate of sedimentation. In an alkaline environment the particles repulse each other, this state is called "deflocculation". Types of flocculating agents – Electrolytes: alter the electrical barrier between particles and allow the flocs to form e.g. 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 Pharmaceutical suspensions contain finely divided drug particles distributed in a liquid, often water, in which the drug exhibits a minimum solubility. Although the Stokes' equation does not consider all the variables which The type of flocculant used depends on … Flocculating agents are either inorganic salts or water‐soluble organic polymers. particles are of uniform shape and size and that the particles are sufficiently As such, polymers can have an advantage over ionic flocculating agents in that they are less sensitive to added electrolytes. Osmotic agents They are added to adjust osmotic pressure comparable to biological fluid. Flocculants are used in water treatment processes to improve the … In suspensions, a liquid and an insoluble solid meet to form an interface. , Surfactants, Polymeric flocculating agents. A pharmaceutical suspension is a coarse dispersion of insoluble solid particles in a liquid medium. 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. Floccules have approximately the same size particles; therefore a clear Buffers and pH adjusting agents They are added to stabilize the suspension to a desired pH range. Coloring agents They are added to impart desired color to suspension … and r2 is the density of the medium of floccules or clusters as particles are held loosely together by weak Suspending agent excipients help active pharmaceutical ingredients stay suspended in the formulation and prevent caking at the bottom of the container. Article Received on 19 October. they will not cake and may be easily redispersed by shaking the suspension. Since the particles are linked together only loosely, process. Effect on wetting Surface-active agents decrease the contact angle of insoluble particles, enabling greater wetting by the vehicle. 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 Practically speaking, the viscosity of the dispersion 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. 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: Ideally, the system should (rheologically) be pseudoplastic; Caking. The Pharmaceutics and Compounding Laboratory. reducing the movement (sedimentation) of suspended particles and physically 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). Suspending agents which are thixotropic upon shaking, they remain fluid long enough to be Suspensions of insoluble drugs may also be used externally, often as protective agents. Polymers can play an important role as flocculating agents in pharmaceutical suspensions. Suspended particles should also be small and uniform in size to provide a smooth and elegant product that is … 7. Normally, in an acid environment, the particles of an argillaceous material are attracted to each other, this state is called "flocculation". Suspending or thickening If the absolute value of the zeta-potential is too high the system deflocculates because of increased repulsion and the dispersion cakes. 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. Now we need some means to reduce - KCl / NaCl E.g.Procaine ... Flocculating Agents Flocculating agents decreases zeta potential of … 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. medium is the only other Stoke's variable affecting sedimentation rate rate in the flocculated suspension. and ho is the viscosity of the 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. (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. 2.2.2 Flocculating Agents. settling rate and an appreciation of the variables governing the sedimentation Flocculating agent changes zeta-potential of the particles (it can be electrolyte, charged surfactant or charged polymer adsorbing on a surface). Background: Nitrofurantoin is a nitrofuran antibiotic that has been used for treatment of urinary tract against positive and negative bacteria. NaCl 0.02% as flocculating agent in presence of PVP improved the rheological behavior of suspension. 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. • Sulfate, citrates, phosphates salts The components of each category are individually selected for their use in the preparation of orally, topically, or parenterally administered suspensions. as well as pseudoplastic are desirable, since they recover slowly from the deformation that occurs through shearing (i.e. 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. 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. This, in turn, assists product homogeneity and decreases aggregation. that is, it should have high viscosity at low shear rates (during storage) • Wetting Agents Non-ionic surfactants are most commonly used as wetting agents in pharmaceutical suspension. systems in which rapid particle settling is the primary factor leading Box 789, Piscatawqy, NJ 08854 (U.S.A.) (Received February 23rd, 1981 (Revised version July 21 st, … Settling or sedimentation is pro… The formulation of a pharmaceutical suspension requires careful consideration of how to ensure homogeneous drug distribution during administration. Flocculating Agents flocculating agents decreases zeta potential of the suspended charged particle and thus cause aggregation (flock formation) of the particles. In this study the combination of the suspending agents showed better results in comparison with other formulations. 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. addition of the flocculating agent, at some critical concentration, negates ), and rheologic aspects. 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. Examples of flocculating agents are: • Neutral electrolytes such as KCl, NaCl. Rheological studies showed pseudoplastic behavior for all suspensions prepared by combination of the suspending agents. Flocculating agents They are added to floc the drug particles Thickeners They are added to increase the viscosity of suspension. Controlled flocculation can be achieved by a combination of control of particle size and the use of flocculating agents. stabilizing the product. FVu/Vo. 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. and low viscosity at high shear rates (during shaking, pouring, or spreading). Flocculating agents are electrolytes which carry an electrical charge opposite that of the net zeta potential of the suspended particles. Physical stability in suspensions is controlled by (1) the addition Finally, drugs in suspension are chemically more stable than in solution. Packaging and storage of suspensions: All suspensions should be packaged in wide mouth container having adequate airspace above the liquid … 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. poured and spread). Flocculating agents are electrolytes which carry an electrical charge The concentration used is less than 0.5 %. to physical instability and lack of dosage uniformity in the product. 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. particles (cm), r1 its density van der Waals forces. 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. Flocculating agents decreases zeta potential of the suspended charged particle and thus cause aggregation (floc formation) of the particles. 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. Examples of flocculating agents used in pharmaceutical suspension (usually at concentrations 0.01 – 1.00 %) include sodium or potassium chloride, aluminum chloride, calcium salts, … Surface-active agents may influence the stability of pharmaceutical suspensions in several ways. affect the stability of a suspension, it gives an approximation of the Zatz, P. Sarpotdar, G. Gergich and A. 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