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