| الملخص | Abstract
This work has been carried out to develop national drug product contains (2.5 mg / ml) clonazepam as oral drop; it is used for the treatment of epilepsy in infants and children.
Several gel formulations were prepared using different oral drop bases and preservatives. Selection of best formula relied solely on physic-chemical testing of sample exposed to thermal stresses.
Stability study was conducted on the product for (6) months at different temperatures and relative humidity to determine the expiration date and the best storage conditions.
From the study we obtained an oral drop of good clear thick solution. The expiry date calculated to be not less than (2) years.
Keywords:- clonazepam, epilepsy, oral drop
Introduction
Epilepsy is a chronic medical disorder or condition, usually resulting in unpredictable , unprovoked recurrent seizures that affect a variety of mental and physical functions. It is one of the most common neurological diseases, affecting more than (3 million) people in the U.S [1]. and about (50 million) people worldwide[2]. Epilepsy was one of the first brain disorders to be described. It was mentioned in ancient Babylon more than (3.000 years) ago[3]. Through the ages, the strange behavior caused by some seizures has led to the creation of numerous superstitions and prejudices. Effective pharmaceutical ingredients must be formulated in a suitable dosage form to enable the patient to get active and safe drug with good features. Clonazepam belongs to a group of medicines called benzodiazepines, it is used for the treatment of epilepsy in infants, children and adults, and they are thought to work by their action on brain chemicals [4].Clonazepam is a slightly yellowish, crystalline powder, practically insoluble in water, slightly soluble in alcohol and in methanol[5]. The formula of clonazepam oral drop contains clonazepam (2.5 mg / ml) as an active ingredient and it is a generic drug that is not manufactured in the Iraqi factories, Therefore, the aim of this study is to prepare an Iraqi formula for this dosage form with its stability study that is to be compatible with specifications of British pharmacopeia. This study is necessary and it's considered to be one of the important documents for the purposes of registration in the Iraqi ministry of health.
Methods of work
Prepare the formulation constituents used in preparing of clonazepam oral drop
(2.5 mg / ml) is presented in table (1).
In suitable Pyrex beaker transfer the following materials, sodium saccharin , sodium citrate, citric acid and distilled water then heat at (70 ◦C) for (15 min) with stirring . In another suitable beaker transfer the stated amount of propylene glycol and heat on water bath at (50 ◦C) then dissolve clonazepam with continuous stirring . In another suitable beaker transfer the following materials : methyl paraben , propyle paraben ,ethanol (96 %) , glycerin, sorbitol, and peach flavor, then mix for (10 min) . All the beakers contents were mixed together with stirring for (15 min) , then ، the (pH) was checked with adjustment, since it should be between (4 - 5.5) , then ، the product was filled in a (20 ml) amber glass bottle with dropper.
Table -1- list of ingredients
Item No. Constituents Quantity / 100ml
1
2
3
4
5
6
7
8
9
10
11
12 Clonazepam
Citric acid
Ethanol 96%
Glycerin
Methyl paraben
Propylparaben
Peach flavor
Propylene glycol
Sodium saccharin
Sodium citrate
Sorbitol
Deionized water 0.25 g
0.001 g
2.0 g
5.0 g
0.15 g
0.05 g
0.005 g
5.0 g
0.2 g
0.002 g
10 g
Add to 100 ml
Method of analysis: )HPLC( method for analysis were followed according to the following: For each 1ml solution that contains (2.5 mg) clonazepam
Specifications Test No.
British pharmacopeia 2013 with modified. Assay method 1
(95 - 105 ) % Assay limit 2
4 - 5.5 )) pH limit 3
C18 15 cm×3.9
254 nm.
0.8 ml/min.
acetonitrile
50% acetonitril and 50% water
HPLC conditions :
A. Colum :
B. Detection :
C. Flow rate :
D. Solvent :
E. Mobile phase : 4
Assay:
Standard:
Weigh accurately (50 mg) of clonazepam standard and dissolve to (100 ml) with acetonitrile, then dilute (1 ml) of this solution to (10 ml) with acetonitrile, this will produce a concentration of (0.05 mg / ml) clonazepam.
Test:
Take (1ml) of the sample, complete volume up to (50 ml) with acetonitrile, mix well, and then filter, this solution has a concentration of (0.05 mg / ml) clonazepam.
Procedure: separately inject equal volume (10 µl) of the standard and test solutions into the chromatograph, record the chromatograms and measure the area under the curve.
Calculation:
AUC.Test
% of clonazepam =--------------- X 100
AUC.STD.
AUC = Area under the curve
Stability study:
Stability study was conducted on the product for (6) months at different temperatures (room temperature,40,50,60) ◦C to determine the expiration date and the best storage conditions.
Results and discussion
In this study, different formulas of oral drop were prepared according to the specification of British Pharmacopoeia 2013. A clear thick solution oral drop of acceptable consistency was produced .
The product showed a good stability ( assay , pH, appearance ) at different temperatures (25, 40, 50, and 60) ◦C.
The product was chemically stable at all above temperatures .
The prepared clonazepam drops was found to be compatable with the stated Pharmacopoeial specifications and the results of stability studies are presented in tables (2) ,(3) , (4).
According to this study , the expiration date has been estimated to be not less than (2) years from the date of manufacturing at room temperature.
Table -2-the physical – chemical changes of Clonazepam oral drop (2.5 mg / ml) within time at different temperatures. (4)
Storage time (month) Temp. % of Clonazepam pH
(4 - 5.5) appearance
Zero time R.T 99.5 4.95 Clear faint yellow
1 RT 99.45 4.85 Clear faint yellow
40 C° 98.6 4.95 Clear faint yellow
50 C° 98.21 4.95 Clear faint yellow
60 C° 98.15 4.95 Clear faint yellow
2
R.T 99.40 4.9 Clear faint yellow
40 C° 98.53 4.9 Clear faint yellow
50 C° 98.21 4.9 Clear faint yellow
60 C° 98.1 4.9 Clear faint yellow
3
R.T 99.40 4.80 Clear faint yellow
40 C° 98.3 4.85 Clear faint yellow
50 C° 98.09 4.85 Clear faint yellow
60 C° 97.9 4.85 Clear faint yellow
4
R.T 99.35 4.8 Clear faint yellow
40 C° 98 4.8 Clear faint yellow
50 C° 98.01 4.8 Clear faint yellow
60 C° 97.8 4.8 Clear faint yellow
5
R.T 99.25 4.8 Clear faint yellow
40 C° 97.8 4.75 Clear faint yellow
50 C° 97.16 4.75 Clear faint yellow
60 C° 96.6 4.7 Clear faint yellow
6
R.T 99.2 4.7 Clear faint yellow
40 C° 97.65 4.63 Clear faint yellow
50 C° 96.21 4.65 Clear faint yellow
60 C° 96.1 4.6 Clear faint yellow
Table - 3 -the stability of Clonazepam oral drop, concentration of Clonazepam at zero time =99.48% of the label amount
Concentration at 60°C (%) Concentration at 50°C (%) Concentration at 40°C (%) Concentration at R.T (%) Time / day
98.15 98.21 99.45 99.45 30
98.1 98.21 98.53 99.40 60
97.9 98.09 98.3 99.40 90
97.8 98.01 98 99.35 120
96.6 97.16 97.8 99.25 150
96.1 96.21 97.65 99.2 180
Zero - order rate of reaction is expected for kinetic of Clonazepam oral drop particularly in the first stage of reduction of concentration.
T95%=0.05C/K
Where:
C=concentration at zero time
K= rate of reaction
T= time
Table -4- The T95% at different temperatures.
T95% Year T95% day Temp.
3 1095 R.T
2.8 1022 40°C
2.5 912.5 50°C
2.3 839.5 60°C
References
1- Epilepsy Foundation About epilepsy and seizures. Available at: www.epilepsyfoundation.org/about/statistics.cfm. Accessed January 10, 2010.
2-World Health Organization Epilepsy: Key facts. Available at: www.who.int/mediacentre/factsheets/fs999/en Accessed June 7, 2010.
3- National Institute of Neurological Disorders and Stroke . Seizures and epilepsy: Hope through research. Available at: www.ninds.nih.gov/disorders/epilepsy/detail_epilepsy.htm. Accessed January 19, 2010.
4- Sean C Sweetman, 2011, printed by LEGO S.P.A.,Martindale 37 the complete Drug Reference, Pharmaceutical Press, USA.
5-The British Pharmacopoeia ,The Pharmaceutical Press, London,UK,2013.389 - 391.
6- Kim Huynh , (2009) , Accelerating aging, Handbook of stability testing in pharmaceutical development,springer ,USA . | en_US |
