EXTEMPORANEOUS PREPARATIONS BY SANA GHAYAS. LEARNING OBJECTIVES: At the end of this lecture, students will be able to: Know about extemporaneous dispensing. Define different dosage forms
At the end of this lecture, students will be able to:
FORMULATION OF SOLUTION:
Following should be determined before formulating a solution:
Medium in which ingredients of medicine are dissolved or dispersed.
FORMULATION OF SUSPENSION:
PROPERTIES OF A GOOD PHARMACEUTICAL SUSPENSION
SUSPENSIONS AS ORAL DOSAGE FORMS
Formulation by the HLB method
e.g. butylatedhydroxyanisole (BHA) or butylatedhydroxytoluene (BHT). Ethyl, propyl or dodecylgallate may also used.
Desirable properties of a preservative for emulsions
Preservatives commonly used in emulsions
Colour and flavor
The main difficulties encountered in practice are listed here.
EMULSIONS AS ORAL DOSAGE FORMS
BASES FOR OINTMENTS AND OINTMENT TYPE PASTES
They may be classified into four main groups:
Concentration of tragacanth from 2%-5% produce gels of increasing viscosity.
SODIUM ALGINATE GELS:
A concentration of 1.5% produces fluid gels and 5-10% gels are suitable as dermatological vehicles.
The required concentration is usually between 10% and 20%, depending on the grade of PVA and the desired viscosity.
Advantages of these bases over theobroma oil:
Disadvantages of synthetic bases include:
(c) Macrogols (polyethylene glycols)
Use of displacement values (Method for determining displacement value)
Using a nominal 1 g mould, Prepare and weigh six suppositories of unmedicated base = ag
Prepare base containing 30% medicament, fill six moulds and weigh six suppositories = bg
Calculate the amount of base, cg and medicament d g in the six suppositories c = 70% b and d = 30% b
Therefore the amount of base displaced by
displacement value = __d______
Weight of six unmedicatedsuppos. = 6.0 gWeight of six suppos. Containing 30% drug = 7.5 g
Base = 70% of 7.5 = 5.25
Drug = 30% of 7.5 = 2.25
Base displaced by 2.25 g = 6 - 5.25 = 0.75 g
Therefore the displacement value of the drug = 2.25/0.75 =3
Method for using displacement value
Required: to prepare for 8 suppositories each containing 300 mg drug of displacement value 3 using a nominal 1 g mould.
Total amount of drugs required = 8 x 300 mg = 2.4 g
This will displace 2.4/3= 0.8 g of base
Therefore amount of base required = 8-0.8 = 7.2 g
Preparation of suppositories with a fatty base
Preparation of suppositories with a macrogol base
LABEL AND ADVICE
On small scale, granules are made with a mortar and pestle and suitable sieves.
They are prepared using method as for undivided oral powders.
Sieve size should be 180 µm.
1. UNDIVIDED POWDERS AS ORAL DOSAGE FORMS:
2. DIVIDED POWDERS AS ORAL DOSAGE FORMS:
4. BULK POWDERS FOR EXTERNAL USE
ORAL UNIT DOSAGE FORMS have accurately measured amount of medicaments in a single dosage unit
ADVANTAGES OF ORAL UNIT DOSAGE FORMS:
DISADVANTAGES OF ORAL UNIT DOSAGE FORMS:
SUPPLY OF TABLETS FROM BULK PACK:
CONTAINERS FOR TABLETS
SPECIAL LABELS FOR TABLETS AND ADVICE FOR PATIENTS:
Cap. 000 00 0 1 2 3 4 5
Content 950 650 450 300 250 200 150 100
ADVANTAGES OF HARD GELATIN CAPSULE: