PHYSICAL PROPERTIES OF DRUG: Physical Form

PHYSICAL PROPERTIES OF DRUG AND THEIR EFFECT ON FORMULATION, STABILITY & BIOAVAILABILITY:

1.      Physical form:

Generally:

·         Solid

·         Liquid

·         Gas

Solid:

·         Tablet, Capsule & powder etc.

·         Formulation:

o   Easy for prepare formulation compare to other

§  By direct compression

§  Wet granulation

o   Patient compliance

o   Dose uniformity

o   Easy to handle

o   Packing easily

·         Stability:

o   High stability compare to other

o   None or less microbial growth

o   Not require critical storage condition

o   Less chances of breakage and loss of dosage form

·         Bioavailability:

o   Less compare to other

o   Because three step involve

§  Disintegration

§  Dissolution

§  Absorption

o   Improve by various techniques, size reduction, addition of disintegrating agent

Liquid:

·         Suspension, emulsion, syrup, Injection etc.

·         Formulation:

o   Hard to prepare compare to solid dosage form

o   Non-uniformity in dosage form

o   Miscibility problem

§  Oil phase / Aqueous phase

o   Mixing problems

o   Non patient compliance

o   Hard to handle and transportation

·         Stability:

o   Less stable compare to solid

o   Chances of microbial growth, preservative must be added to prevent this

o   Liquid phase have higher chances of microbial contamination.

o   Sugar syrup prevents microbial growth and overcome bitter taste of drug, that’s why used in many liquid formulations.

·         Bioavailability:

o   Good bioavailability

o   Quick response of drug, Bcz

§  Disintegration not perform in liquid dosage form

o   Improve by various techniques, size reduction

Gas:

·         Aerosol, Foam

·         Formulation:

o   Very hard to formulate

o   Formulation by compressed gas

o   Handling problems

o   Packing problems

o   Pressurized and convert into liquid form to prepare

o   Special techniques used for the preparation

·         Stability:

o   Least stable

o   Convert in liquid by compression to improve its stability

·         Bioavailability:

o   Best bioavailable, Bcz

§  Direct absorption occurs

§  From mucous membrane of nose or buccal cavity

o   Quick action compare to solid and liquid

Improve by size reduction