2.Water,Water miscible and water immiscible Vehicles in sterile dosage forms.ppt

A vehicle is the component of a sterile formulation that serves as the medium for delivering the active drug to the body. It provides physical form, assists in drug solubilization or suspension, influences drug stability, and affects the rate and extent of drug absorption.

Functions of vehicles:

Solubilization of drug: To dissolve drugs that are not sufficiently soluble in water.

Suspension medium: To disperse insoluble drugs evenly.

Stabilization: To protect the drug from hydrolysis, oxidation, or photodegradation.

Control of tonicity and viscosity: To ensure compatibility with body fluids and ease of injection.

Facilitation of administration: To provide the desired flow properties and injectability.

2. Requirements of Vehicles for Sterile Preparations

Because sterile dosage forms are intended for parenteral, ophthalmic, or other highly sensitive routes, vehicles must meet strict pharmaceutical and physiological criteria:

Sterility: Must be sterile and remain so throughout storage and use.

Pyrogen-free: Free from bacterial endotoxins and other fever-producing agents.

Isotonicity: Should not cause osmotic damage to cells or tissues.

Non-toxicity and non-irritancy: Must be physiologically compatible with body tissues and fluids.

Chemical stability: Should not react with drug or packaging components.

Clarity: For parenteral and ophthalmic use, vehicles should be clear and free of particulate matter.

Appropriate viscosity: Should ensure ease of injection or instillation without pain or tissue damage.

1. VEHICLES IN STERILE DOSAGE
FORMS

3. Water is the most frequently used vehicle for
sterile products since it is vehicle for all natural
fluids.
One of the most important test is total solids
content and gravimetric evaluation. Electric
measurement of conductivity is less time
consuming test electrodes are immersed in water
specific conductance depends upon ionic content
of water.micromhos. Ionic content is measured
as ppm.High purity water can be obtained by
distillation or reverse osmosis.10ppm of total
solids are officially permitted conductivity not
greater than 1 micromhos.approximately 0.1ppm
of NaCl

10. Distillation:Distillation is the process converting water from
a liquid to its gaseous form (steam) Steam is pure gaseous water.

13. Comression distillation: In vapour
compression distillation feed water is heated from an external source in
evaporator to boiling. The vapors produced in the tubes are separated
from the entire distill in a separator and conveyed to compressor that
compresses vapor and raises its temperature to approximately 107
degree celcius. It then flows to steam chest where it condenses on
outer surface of tubes containing distill. Vapor is condensed and drawn
as distillate. It gives up heat to bring the distill to its boiling point.

15. Reverse osmosis Selective permeation of
molecules through a semipermeable membrane water passes from
high concentration to low concentration(Reverse osmosis)Pressure
applied is 200 to 400psig to permeate water through
membrane.Membranes used are cellulose acetate or nylon.
•Combined RO and distillation method:In
this method water is first allowed to run
through RO to remove heavy
contamination and then distilled.

16. The system should be consistent and reliable will produce physical,
chemical microbiological quality of water.

19. Storage and Distribution
Water is collected in aholding tank for use. Capacity several litres. WFI should be held at high
temperature as 80 degree centigrade to prevent microbial contamination.At room temperature it
can be stored maximum for 24 hrs.The construction material of tank is stainless steel 316. A high
quality stainless steel.The tanks can be lined with glass or tin.

20. Purity:
Total organic carbon limit:500ppb
Conductivty:
pH :5 to 7
Microbial limit: NMT 10CFU per 100ml
Endotoxin limit:NMT 0.25 endotoxin
unit per ml