Preformulation studies on paracetamol: Industrial Pharmacy Lab
To evaluate the pre-formulation parameters of paracetamol
Preformulation commences when a newly synthesized drug shows sufficient pharmacological promise in animal models to warrant an evaluation in man. These studies should focus on the properties of a new compound that could affect the drug performance in the development of an efficacious dosage form. A thorough understanding of these properties may ultimately provide a rationale for formulation design or support the need for molecular modification.
Preformulation involves the application of biopharmaceutical principles to physicochemical parameters of drug substances characterized with the goal of designing an optimum drug delivery system. Characterization of the drug molecule is a very important step in the pre-formulation stage of product development.
- Name of the compound: paracetamol
- Chemical name:n-acetyl-para-aminopheno.
- Molecular formula: C8H9NO2
- Molecular weight: 151.165 g·mol−1
- Description: white powder.
- Category: pain and fever , a nonsteroidal anti-inflammatory drug.
- dose: 500 mg.
- Storage: Store protected from light and moisture
apparent bulk density (ρb) was determined by placing the granules into a graduated cylinder and measuring the volume (vb) and weight (m) “as it is”.
pb = m/vb
Weight of sample =
Volume of sample =
Bulk density =
The measuring cylinder containing a known mass of granules was tapped 100 times using a bulk density apparatus. The minimum volume (vt) occupied in the cylinder and the weight (m) of the granules was measured. The tapped density (pt) was calculated using the formula.
pb = m/vb
tapped density =
It is the measure of potential strength that power could build up in its arch in a hopper and also the ease with which such an arch could be broken. The compressibility index of the granules was determined by using the formula.
Ci (%) = [(pt-pt/pt)] x 100
Bulk density =
Tapped density =
|Carr’s index (%)||Type of flow|
|18-21||Fair to passable|
It is the measure of the flow property of the drug.
hausener’s ratio = pt/pb
Angle of repose:
It is the maximum angle possible between the surface of the pile of the powder and the horizontal plane. The angle of repose was measured by using the funnel method, which indicates the flow ability of the granules.
Angle of repose is determined by the following formula.
tan θ = h/r
where θ = angle of repose
h and r are the height and radius of the powder cone.
θ = tan-1 h/r
|Angle of repose (θ)||Type of flow|
The solubility of a drug is an important physicochemical property because it affects the bioavailability of the drug, the rate of drug release into the dissolution medium and consequently, the therapeutic efficiency of the pharmaceutical product. This is a valuable step in developing a formulation. Solubility is usually determined in a variety of commonly used solvents and some oils if the molecules are lipophilic. The solubility of material is usually determined by the saturated/ equilibrium solubility method, which employs a saturated solution of the material, where the excess quantity of drug is taken in 10ml of each solvent and occasionally stirred for 24hrs at room temperature and the sample was filtered and the filtrate was suitably diluted and analyzed spectrophotometrically at 249nm
|Solubility||Parts of solvent required for 1 part of solute|
|Very soluble||Less than 1|
|Freely soluble||From 1 to 10|
|Soluble||From 10 to 30|
|Sparingly soluble||From 30 to 100|
|Slightly soluble||From 100 to 1000|
|Very slightly soluble||From 1000 to 10000|
|Practically insoluble||10000 or more|
The solvents used are distilled water, ethanol, chloroform and 0.1N HCl
|S.no||Solvent||Absorbance||Dilution factor||Concentration (mg/ml)||Solubility (parts required to dissolve 1g of drug)|
|3.||0.1 N HCl|
a 50% w/v drug solution was analysed for its ph by using pH meter.
Industrial Pharmacy I Practical
- Preformulation studies on paracetamol/aspirin/or any other drug
- Preparation and evaluation of Paracetamol tablets
- Preparation and evaluation of Aspirin tablets
- Coating of tablets- film coating of tables/granules
- Preparation and evaluation of Tetracycline capsules
- Preparation of Calcium Gluconate injection
- Preparation of Ascorbic Acid injection
- Quality control test of (as per IP) marketed tablets and capsules
- Preparation of Eye drops/ and Eye ointments
- Preparation of Creams (cold / vanishing cream)
- Evaluation of Glass containers (as per IP)
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