Download

PHARMACEUTICAL SUSPENSIONS AND EMULSIONS






Advertisement
/ 17 []
Download Presentation
Comments
Sophia
From:
|  
(3755) |   (0) |   (0)
Views: 517 | Added:
Rate Presentation: 0 0
Description:
PHARMACEUTICAL SUSPENSIONS AND EMULSIONS. Coarse Dispersions. Oil-in-water emulsions (o/w) Water-in-oil (w/o). (Lyophobic colloids). Suspension: Solid drug in liquid vehicle. Emulsion: Liquid drug in liquid vehicle:. Reasons for Use. Drug is insoluble
PHARMACEUTICAL SUSPENSIONS AND EMULSIONS

An Image/Link below is provided (as is) to

Download Policy: Content on the Website is provided to you AS IS for your information and personal use only and may not be sold or licensed nor shared on other sites. SlideServe reserves the right to change this policy at anytime. While downloading, If for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.











- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -




Slide 1

PHARMACEUTICAL SUSPENSIONS AND EMULSIONS

Slide 2

Coarse Dispersions

  • Oil-in-water emulsions (o/w)

  • Water-in-oil (w/o)

(Lyophobic colloids)

  • Suspension:Soliddrug in liquid vehicle

  • Emulsion:Liquiddrug in liquid vehicle:

Slide 3

Reasons for Use

  • Drug is insoluble

  • Drug is more stable in suspension or emulsion

  • There is a need to control the rate of releaseof the drug

  • Drug hasbad taste (oral)

Slide 4

Routes of Administration

  • Oral

  • Ocular

  • Otic

  • Rectal

  • Parenteral

  • Topical

Slide 5

I. Formulation of Suspensions

Slide 6

Wetting

Wetting agent

Slide 7

Well Formulated Suspension

  • Resuspend easily upon shaking

  • Settle rapidly after shaking

  • Homogeneous mix of drug

  • Physically and chemically stable during its shelf life

  • Sterile (parenteral, ocular)

  • Gets into syringe (parenteral, ocular)

Slide 8

“External” Forces Acting on Particles

  • Sedimentation equilibrium:Gravity is neutralized by Brownian movement

Gravity

Brownian Movement

V(-o)g

2-5 m

Slide 9

Settling and Aggregation

  • The suspension shall form loose networks of flocks that settle rapidly, do not form cakes and are easy to resuspend.

  • Settling and aggregation may result in formation ofcakes(suspension) that is difficult to resuspend orphase separation(emulsion)

flock

cake

Slide 10

Sediment Volume

F={volume of sediment Vu}/{original volume Vo}

  • Vu

  • Vo

  • Vo

  • Vu

F=0.5

F=1.0

F=1.5

Slide 11

DLVO: Optimal Distance

Energy

No flocks can form

Repulsion

Attraction

Attraction

Distance

Slide 12

+

-

Controlled Flocculation

  • Flocculating agent changes zeta-potential of the particles (it can be electrolyte, charged surfactant or charged polymer adsorbing on a surface).

  • If the absolutevalue of the zeta-potential is too high the system deflocculates because of increased repulsion and the dispersion cakes.

+

Non-caking

Caking

Caking

F=Vu/Vo

Flocculating Agent

-

+

-

+

Zeta-potential

Slide 13

II. Formulation of Emulsions

Slide 14

Emulsification

Emulsifier

Slide 15

HLB and Use of Surfactants

Amphiphilic surfactants are characterized by the hydrophilic-lipophilic balance (HLB): a relative ratio of polar and non-polar groups in the surfactant

HLB ca. 1 to 3.5: Antifoams

HLB ca. 3.5 to 8: Water-in-Oil Emulsifiers

HLB ca. 7 to 9: Wetting and spreading agents

HLB ca. 8 to 16: Oil-in-Water Emulsifiers

HLB ca. 13 to 16: Detergents

HLB ca. 15 to 40: Solubilizers

Slide 16

Required HLB

HLB needed for emulsification of the oil phase. If there are several oil ingredients the required HLB is calculated as a sum of their respective required HLB multiplied by the fraction of each.

  • Calculate the required HLB for the oil phase of the following o/w emulsion: cetyl alcohol 15 g., white wax 1g. Lanolin 2 g, emulsifier (q.s.), glycerin 5 g. water 100 g.

    • Required HLB Fraction

    • (from reference)

    • Cetyl alcohol 15 x 15/18 12.5

    • White wax 12 x 1/18 0.7

    • Lanolin 10 x 2/18 1.1

    • Total required HLB 14.3

Slide 17

HLB of Surfactant Blend

Surfactant blends are commonly used to obtain desired emulsifying properties.

  • What is the HLB of the mixture of 40 % Span 60 (HLB = 4.7) and 60 % Tween 60 (HLB = 14.9)?

    • HLB of mixture:

      • 4.7 x 0.4 + 14.9 x 0.6 = 10.8

  • In what proportion should Span 80 (HLB = 4.3) and Tween 80 (HLB = 15.0) be mixed to obtain “required” HLB of 12.0?

    • 4.3.(1-x) + 15.x = 12 x = 0.72

    • 72 % Tween 80 and 28 % Span 80


Copyright © 2014 SlideServe. All rights reserved | Powered By DigitalOfficePro