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