Formulation and Evaluation of Atenolol Floating Microsphere

About Author: Mr. Patil Kuldip, Tekade B. W., Thakare V. M., Dr. Patil V. R.
T. V. E. S’s College of Pharmacy,
Faizpur (M.S.), India

The purpose of this research was to prepare a floating drug delivery system of atenolol. In the present study, preparation of atenololfloating microspheres, evaluation of Floating Drug Delivery System (FDDS) in vitro, prediction of the release, and optimization of stirring speed and polymers ratio to match target release profile was investigated. Floating microspheres were prepared by solvent evaporation (Oil-in-water emulsion) technique using hydroxylpropyl methylcellulose (HPMC), Ethyl cellulose (EC) and Eudrajit S100 as the rate controlling polymers. Particle size analysis, drug entrapment efficiency, surface topography, and release studies were performed. Results showed that the polymer ratio and stirring speed affected the size, incorporation efficiency and drug release of microspheres (> 12 h), and the best results were obtained at the ratio of EC (1:3). The mean particle size of prepared floating microspheres increased but the drug release rate from the microspheres decreased as the polymer concentration increased. The developed floating microspheres of atenolol may be used in clinic for prolonged drug release in stomach for at least 12 hrs, thereby improving the bioavailability and patient compliance.

Reference ID: PHARMATUTOR-ART-1128

The objective of the present investigation is to prepare floating microsphere of atenololto improve the bioavailability by increasing residence time in stomach. Cardiac dysrhythmia (also known as arrhythmia) is a term for any of a large and heterogeneous group of conditions in which there is abnormal electrical activity in the heart.1 the heart beat may be too fast or too slow, and may be regular or irregular. Some arrhythmias are life-threatening medical emergencies that can result in arrest and sudden death2,Atenolol is a non-selective beta-blocker mainly used in the treatment of hypertension and arrhythmia. The plasma half life of atenolol is short hence requiring taking thrice a day and it is decompose at alkaline pH3. The recommended adult oral dosage of atenolol is 10 mg 2 to 3 times in day4. Dosage forms that can be retained in stomach are called gastro retentive drug delivery systems (GRDDS). Gastro retentive systems can remain in the gastric region for several hours and hence significantly prolong the gastric residence time of drugs5. Prolonged gastric retention improves bioavailability, reduces drug waste and improves solubility for drugs that are less soluble in a high pH environment. It has applications also for local drug delivery to the stomach and proximal small intestines5. Gastric retention will provide advantages such as the delivery of drugs with narrow absorption windows in the small intestinal region6. Also, longer residence time in the stomach could be advantageous for local action in the upper part of the small intestine, for example treatment of hypertension and arrhythmia.

Atenolol was obtained from market, EthylCellulose & hydroxylpropyl methylcellulose fromColorcon Pvt Ltd, Mumbai.Eudrajit S100 from Evonik Pvt Ltd, Mumbai.

Preparation of Microspheres: 7
Floating microspheres containing Atenolol were prepared using emulsion solvent evaporation technique. For the preparation of floating microspheres, the rate controlling polymers in varying concentration (Drug: polymer, 1:1, 1:2 and 1:3). , The drug and polymer mixture (1:1, 1:2 and 1:3) was dissolved in a Ethanol and dichloromethane (15ml) containing 0.01% of Tween 80, The resultant solution was stirred with a stirrer for 1 hour at 700 rpm. Various batches of floating microsphere was shown in table no. The parameter use in the formulation are given below .the formed floating microspheres were filtered and washed with water and dried at room temperature.

Evaluation of floating microspheres of Atenolol
Particle size analysis:

The sizes of floating microspheres were measured by laser diffraction particle size analyzer. Firstly, 1gm offloating microspheres was floated in 200 ml of containing 0.02 % of Tween 20 in aqueous solution and stirred at 37 ± 0.5 °C. Second, particle size distribution was obtained when a laser light passed through the microspheres and then diffracted the intensity in an angular distribution. The data obtained were evaluated using volume distribution diameter (d) values of 10%, 50% and 90%.

Angle of repose:9
The angle of repose of floating microspheres was determined by fixed funnel method. The floating microspheres were allowed to fall freely through a funnel until apex of conical pile just touched the tip of the funnel. The angle of repose θ was determined according to the following formula

θ= tan-1 h/r

Where, h = height of pile, r = radius of the pile formed by the floating microspheres.

Bulk density and tapped density:9
The bulk density and tapped density of floating microspheres were determined by the tapping method.

Percentage compressibility index /Carr’s index:9
The percentage compressibility index was calculated according to following formula

                                               Tapped density – Bulk density
% Compressibility Index =     ---------------------------------------   X 100
                                                           Tapped density

Hausner’s ratio:9
It is calculated by the following formula

                                 Tapped density
Hausner’s Ratio =    ---------------------
Bulk density

Percentage yield:10
The percentage yield of different formulations was determined by weighing the floating microspheres after drying. The percentage yield was calculated as follows.

                    Total weight of floating microspheres
% Yield =  ----------------------------------------------------   X 100
Total weight of drug and polymer



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