Farmasetika Dasar II Najma Annuria Fithri, M.Sc., Apt.

Universitas Sriwijaya

Genap 2013/2014

Pertemuan 7 Inkompatibilitas Sediaan Cair

Incompatibility

• Pharmaceutical

- Physical immiscibility, insolubility, precipitation, liquefication

- Chemical sedimentation, redox, colour change, acid base reaction, instability

• Therapeutic

Unwanted response, OD, drug interaction, antagonist action, contraindication

Therapeutical interaction

1. Antagonist action

Ex: vasodilators + vasoconstrictors

2. Hindrance of drug activity

Ex: decomposition (hydrolysis, oxidation)

3. Complex molecule less absorbed drug

Ex: tetracycline + milk

Drug Combination

1. Synergist effect stronger effect

Ex: drugs with similar mechanism of action

2. Antagonist effect weaker effect

Ex: vasodilator + vasoconstrictor

depressant + stimulant

Problem solving - Therapeutical

1. Interlude between drug intake

2. Dosage monitoring

3. Replace one/more drugs

Problem solving - Pharmaceutical

1. Mixing steps modification

2. Co-solvent

3. Replace excipients/active drugs

4. Increase of volume

5. Emulsification emulgator

6. Suspension formation suspending agent

7. Separation of drugs

Example

• R/

Ephedrin 1

Champor 1

Menthol 1

Aq qs ad 100

m.f.pot.

Answer

• Ephedrin water soluble

• Camphor and methol insoluble

Camphor and menthol combined liquefication add water add ephedrin

• R/

Mg carbonate 3

Citric acid 3

Natrii Bic 3

Aq.bull. Ad 100

m.f.pot.

Answer

• Mg carbonate insoluble in water

• Natrii bic + citric acid mix with hot water ad MgCO3 little by little wait until gas bubble dissolve continue addition

• R/ Mercuri iod1 Timol 2 (1:15 alc) Aquadest ad 60 m.f.sol. R/ Terpin hidrat 2 (1:13 alc) Alcohol 15 Glycerin 20 Aq ad 100 m.f.sol.

• R/

Phenobarbital Na 2

Aq.menth.pip.gtt 2

m.f.pot.

R/

Na bromida 5

Ol.sasami 25

Aqua qs ad 120

m.f.pot.

• R/

Sulfadiazine 500

Pot.nig.c.tuss

Syr.thymi. Aa 200 ml

m.f.pot.