international journal of advances in pharmaceutical research

Phani Ratna Prasanth.G, et al. / International Journal of Advances in Pharmaceutical Research 

IJAPR 

Available Online through 

www.ijapronline.org 

Research Paper 

ISSN: 2230 – 7583 

DESIGN, CHARACTERIZATION and EVALUATION OF DEXLANSOPRAZOLE 

ENTERIC COATED PELLETS 

Phani Ratna Prasanth.G* 1 , P.Pavan Kumar 2 , K.Santhi 1 , C.I.Sajeeth 1 

*1 Grace College of Pharmacy, Kodunthirapully, Palakkad, Kerala, India 

2 Natco Pharma limited, Hyderabad, Andhra Pradesh 

Received on 25 – 01 - 2012 Revised on 23 – 03- 2012 Accepted on 27– 04 – 2012 

ABSTRACT 

The first and main aim of the present investigation was to prepare delayed release i.e., enteric coated pellets of 

Dexlansoprazole by using hydroxypropyl methyl cellulose based sub coating and methacrylic acid copolymer 

based enteric coating. By using various concentrations of polymers, it was found to play a great role in delaying 

the release from the enteric coated pellets. The different batches of pellets were prepared by drug suspension 

layering and were developed using fluid bed layering and coating techniques. Ten formulations having alkalizing 

agents, solubilizing agents, polymers at different concentration levels were prepared in sub coating as well as 

enteric coating were prepared. The formulated enteric coated pellets were evaluated for drug content, size analysis, 

particle size analysis and invitro dissolution study in pH 1.2 buffer for 2 hours followed by testing in pH 6.8 buffer. 

Among all the formulations, capsules of F9 batch showed superior properties along with excellent drug release 

(94%) when compared to other formulations. This concluded that FBP technique is a best useful method for 

preparing the enteric coated pellets. DSC study also revealed that there was no chemical interaction between the 

drug and pellets. It was shown better stability that storage conditions were excellent. It can be the good way to 

improve the bioavailability of Dexlansoprazole. 

Key words: Dexlansoprazole, sub coating, Enteric coating, and Fluid bed layering 

INTRODUCTION 

During the past few decades various types of oral 

delayed release formulations have been developed to 

improve the clinical efficacy of drug having short 

half life as well as to improve patient compliance. 

Proton Pump Inhibitors (PPIs) are used in the 

treatment of acid-related gastro-duodenal disorders 

by reducing gastric acid secretion. PPIs are 

substituted benzimidazoles and all share a similiiar 

core structure and mode of action but differ in 

substituent groups. 

Corresponding Author, 

Phani Ratna Prasanth G, 

Email: prasanth_599@yahoo.com 

Contact: +91-7736147009 

The stability of PPIs in aqueous media is a function 

of pH with an increased rate of degradation as the 

pH decreases. Degradation leads to discoloration of 

pellets, film layer or dissolution medium. Exposure 

of Dexlansoprazole to the acid content of stomach 

would lead to significant degradation of the drug and 

hence reduced bioavailability 2 . 

Delayed release dosage form is best formulations 

which are used for drugs that are destroyed in the 

gastric fluids, or cause gastric irritation or are 

absorbed preferably in the intestine. Such 

preparations containing an alkaline core material 

comprising the active substance, a separating layer 

and enteric coating layer 3, 4 . 

In the present study an effort has been made to delay 

the release of drug form the prepared drug loaded 

pellets by using enteric polymers such as HPMC 

Powder 55 S and Eudragit Liquid 100 55. The drug 

having relatively short half life (1 hour) and frequent 

IJAPR / May. 2012/ Vol. 3 / Issue. 5 / 907 - 913 907


dosing is thus necessary to maintain stable plasma 

concentration. 

MATERIALS AND METHODS 

Materials 

Dexlansoprazole, a gift sample from labs of Alkem, 

sugar spheres, PVP K 30, HPMC E5, dibasic sodium 

phosphate, Light magnesium carbonate, sodium 

lauryl sulphate, Mannitol, Eudragit L 100 55, HPMC 

P 55 PEG 4000, Triethyl citrate, diethyl phthalate, 

cetyl alcohol, talc, titanium dioxide, iso propyl 

alcohol were obtained as a gift sample from Alkem 

research center. 

Methods 

Preparation of Dexlansoprazole 30 mg Delayed 

release Pellets 

6, 7, 8, 9 

Drug loading 

Weigh all the ingredients as per the given formula in 

table 1 and prepare the drug solution. Take 500 ml of 

purified water in beaker and kept for stirring under 

mechanical stirrer. Specified quantities of PVP K30, 

HPMC E5, dibasic sodium phosphate, Magnesium 

carbonate and SLS were added slowly and stir it for 

a uniform suspension. Then drug was added in the 

above solution and stirring was continued for 30 

mins to form a vortex of the solution. Now pass the 

dispersion using Nylon cloth of mesh no 200. The 

solution is now ready for drug loading. Finally the 

drug is loaded using the dispersion over sugar 

spheres in the chamber of FBP. 

Barrier coating: (Sub coating) 5 

Sub coating was done to protect and also for 

increasing the stability of a drug. Mechanical 

strength of pellets is also increased. In order to 

prevent interaction with functional groups contained 

in the enteric film coat, it is one of the advantages to 

combine enteric coatings with sealing coats made up 

of cellulose derivatives. 

500gm water is taken in a beaker and kept it for 

stirring, specified quantities of PVP K30, HPMC E5, 

dibasic sodium phosphate, magnesium carbonate and 

mixed well for 30 min. Add slowly mannitol to the 

coating solution under stirring for 15 min. After 

formation of a suspension the solution is ready for 

sub coating and the drug loaded pellets were coated 

by using Fluidized bed coater. 

Enteric Coating 10 

Step I: 300ml of IPA and 900 ml of acetone were 

taken in a beaker and kept for stirring under a 

mechanical stirrer. 

Step II: All the ingredients should be weighed 

accurately and should be passed through 200# for 

proper formation of dispersion. 

Step III: In another portion of solution add talc and 

titanium dioxide and stir it. 

Step IV: Now step II form was added slowly to step I 

and stirring was done for 20 min until it forms a 

uniform mixture. Add plasticizer to the above 

dispersion. 

Step V: Add dispersion step IV to step III under 

continuous stirring to form a homogenized mixture. 

Now filter through a nylon cloth. Now the filtered 

solution is ready for enteric coating and check the 

pH of the solution. 

Step VI: enteric coating using the dispersion of step 

V over the barrier coated pellets with the help of 

fluidized bed coater. Wurster insert and a bottom 

spray gun. Spread of the solution was carried out at 

at atomization pressure of 2 kg/cm 2 , an inlet 

temperature of 35 o C, spray rate of 6 ml/min and a 

fan speed of 7 to 9. Up on completion of spraying, 

the various loading on sugar spheres were further 

dried at 60 o C inlet temperature for 5 min and the in 

process parameters were given in table 1. The final 

end product was then sieved on top of a 20-mesh 

screen to eliminate fines. 

Evaluation of Pellets 1,12 

Evaluation of pellets must be done to obtain product 

performances. Evaluation at different stages during 

manufacturing process were as follows 

Acid resistance: amount of drug resisted after 2 hr 

in acid was 99.75%. 

Pellets size analysis: Formulated Dexlansoprazole 

delayed release pellets size change during different 

stages such as drug loading, Barrier coating and 

enteric coating of pellets were shown in table no 3 

Particle size distribution: This was done for proper 

coating. Particle size was determined by using SEM. 

Samples of F9 formulation were mounted on metal 

tubes and SEM photograph was taken as shown in 

figure 5. 

Determination of drug contents: Enteric coated 

pellets of Dexlansoprazole 30 mg were transferred to 

100 ml vol. flask, added 70 ml of methanol and 

sonicate for 15 min with intermittent shaking and 

dilute to volume with methanol. Filter through 0.45µ 

filter and further dilute 5 ml of this solution to 100 

ml with mobile phase. Results were tabulated in 

table 4. 

Invitro dissolution studies: An invitro dissolution 

study for the finished product formulation was 

carried out using dissolution USP method I (basket) 

for Dexlansoprazole delayed release pellets. The 

dissolution medium consisted of 900 ml of pH 1.2 

buffer maintained at a temp of 37+0.5 o C and was 

run for 2 hr initially and release should not be more 

than 10%. Transfer the weighed pellets equivalent to 

30 mg of Dexlansoprazole in to each of six jars. 

After 2 hrs the previous acid medium was replaced 

with 900 ml of pH 6.8 buffer and release study was 

done. 



Calculations: % of Dexlansoprazole 

A T W Std 5 900 P 

Dissolved = -----×-------×------×------×------×100 

A s 100 50 LC 100 

Where, 

A T : average of the area counts of the 

Dexlansoprazole peak obtained from the 

chromatograms of Test preparation 

A s: average of the area counts of the Dexlansoprazole 

peak obtained from the chromatograms of the 

standard preparation 

W std : Weight of Dexlansoprazole working standard 

in mg 

P: potency of Dexlansoprazole working standard (% 

on as is basis as dexlansoprazole) 

LC: label claim of Dexlansoprazole mg per capsule. 

Volume with drawal: 5 ml and replaced at same 

temp 

Dilution Factor: 100 

Bath volume: 900 ml 

After specified interval withdraw sample from a 

zone midway between the surface of the medium and 

top of the rotating blade and not less than 1 cm from 

the vessel wall and filter through 0.45 micron 

membrane filter. 

Differential Scanning calorimetry studies: 11 

DSC scan of about 5 mg using an automatic thermal 

analyzer system performed accurately weighed of 

Dexlansoprazol, API and polymers Eudragit and 

HPMC of 1:1 in ratio respectively. Figure no 2, 3, 4 

shows the DSC thermographs of pure drug of 

Dexlansoprazole and polymers. Thermographs 

obtained by DSC studies revealed that the melting 

point of pure drug is 145 O C and that the polymer 

and pure drug shows sharp endothermic peak at 

142.3 O C. Eudragit shows sharp endothermic peak at 

138 o C. From this it may be concluded that the drug 

is in the formulation without interacting with the 

polymer and excipients. 

Stability studies: 

The stability studies of the optimized capsule 

formulation F9 were carried out according to ICH 

guide lines at 40+2 o C/75+5 % RH for two months by 

storing the sample in stability chamber (thermo lab). 

Samples were collected at 15 days interval. 

RESULTS & DISCUSSION 

In the present study delayed drug delivery of 

Dexlansoprazole were successfully developed by 

enteric polymers which offer a suitable and practical 

approach in serving desired dissolution 

characteristics with increased bioavailability. The 

enteric coated pellets size was found to be increased 

during drug loading, barrier coating and enteric 

coating of pellets as shown in table 3. Among all the 

formulations F9 shows invitro dissolution profile 

within acceptable official limit. Particle size 

distribution was also determined for proper coating 

and the micrograph of formulation F9 was shown in 

figure 5. DSC studies with other excipients revealed 

that there was no interaction and also selected 

formulation was stable after stability studies. 

DISCUSSION 

In coating process the enteric coating was done with 

the percentage build up of 25-28% with 8% sub 

coating. Acid resistance test failed up to 26% but at 

28% build up acid resistance test passed. But for 

safer side we coated up to 30% with 8% sub coating. 

Based on the results Formulation F9 was found to be 

satisfactory as it has excellent release properties 

where it has shown an excellent stability. There was 

no significant change in invitro release profile. It 

shows that the formulation F9 was stable. Also from 

the stability studies it was confirmed that it was 

stable under the desired conditions which was shown 

in fig 6 

CONCLUSION 

The aim of the present study was to formulate and 

evaluate delayed release pellets of Dexlansoprazole 

by enteric coating. It is an acid liable drug so it is 

degraded at acidic pH of stomach. So an attempt was 

made to stabilize the drug and by using alkaline 

agent magnesium carbonate. Finally enteric coating 

was given to bypass the stomach. The enteric coating 

was carried out by using enteric polymer HPMC P 

55 S. the core pellets were prepared using suspension 

layering technique in fluid bed process. Sub coating 

was given to core pellets to avoid direct contact of 

drug with enteric coating materials. An average 

weight build up of 8% w/w was given to core pellets. 

Enteric coating was given to sub coated pellets at an 

average weight build up of 30% w/w of sub coated 

pellets and the acid resistance profile is seen. 

Stability studies were also conducted for 2 months 

and it was concluded that the drug release from F9 

formulation was best suitable formulation. 

ACKNOWLEDGEMENTS 

The authors wish to thanks the principal Dr. 

Y.Haribabu; I place on record my gratitude to 

Dr.K.Santhi, Dr. C.I.Sajeeth and management of 

Gracecollege of pharmacy, Kerala for continuous 

support, encouragement and excellent facilities. Very 

special thanks to management of Alkem Research 

centre group for gift samples of drug and providing 

excellent research facilities. 



Formula 

in mg 

Drug 

loading 

Barrier 

coating 

Enteric 

Coating 

TABLE & FIGURES 

Table 1: Design of formulation of Dexlansoprazole delayed release pellets 

Ingredient F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 

Sugar spheres 171 171 171 171 171 171 171 171 171 171 

Dexlansoprazole 30 30 30 30 30 30 30 30 30 30 

PVP K30 2.8 5.6 5.6 - - 5.6 - 5.6 5.6 5.6 

HPMC E-5 - - - 5.6 5.6 - 5.6 - - - 

Dibasic sodium 3.5 3.5 3.5 - - - - - - - 

Phosphate 

Magnesium - - - 3.5 3.5 3.5 3.5 3.5 3.5 3.5 

Carnonate 

SLS 0.59 0.59 0.59 0.59 0.59 0.94 0.94 0.94 0.94 0.94 

PVP K30 10.5 10.5 10.5 - - 10.5 - 10.5 10.5 10.5 

HPMC E-5 - - - 10.5 10.5 - 10.5 - - - 

Dibasic sodium 3.5 3.5 7 - - - - - - - 

phosphate 

Magnesium - - - 7 7 7 7 7 7 7 

carbonate 

Mannitol 76.40 73.60 70.10 70.10 70.10 69.75 62.75 76.75 69.75 62.75 

Eudragit L 100 42 42 42 42 35 - - - - - 

55 

HPMC P 55 S - - - - - 35 40 38 42 49 

Titanium dioxide 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 

Triethyl citrate 1.05 1.05 1.05 1.05 1.05 1.05 - - 1.05 1.05 

Talc 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 

Inlet temperature 

Outlet temperature 

Table 2: In process parameters of coating 

Parameters 

Condition 

Atomization air pressure 

Pan RPM 

Spray rate 

55 o C to 60 o C 

45 o C to 50 o C 

1-2kg/Sq.cm 

8-10 RPM 

70-140 g/min 

Table 3: Sieve analysis of pellets in different stages 

Pellets in different stages 

Size of pellets (µm) 

Core pellets 600-710 

Drug loaded pellets 710-810 

Barrier coated pellets 810-830 

Enteric coated pellets 830-850 



Table 4: Determination of drug contents 

Batch no 

Drug contents 

F3 87.34+0.48 

F4 88.11+0.016 

F5 95.10+0.25 

F6 98.20+0.056 

F7 98.90+0.012 

F8 99.8+0.31 

F9 99.75+0.18 

F10 94.6+0.09 

Where n=3 

Fig 1: Invitro comparative dissolution profile of pellets in pH 6.8 buffer 

Fig 2: DSC of pure drug Dexlansoprazole 

Fig 3: DSC of Dug + HPMC (1:1 ratio) 



Fig 4:DSC of Drug + Eudragit L 100 S (1:1) 

Fig 5: SEM photograph of formulation F9 

Fig 6: Stability study at 40 ± 2 C and 75 ± 5 % RH Dexlansoprazole pellets. 



REFERENCES 

1. Subramanyam C.V.S, Text book of physical 

pharmacy, Page no 180-184 

2.Ijeoma F. Uchegbu and Andreas. G. Schatzlein. 

Polymers in drug delivery:235 

3.Thomas WYl and RobinsonJ. The science and 

practice of pharmacy, 20 th ed, Lippin kette, William 

and Willins:903-911 

4. Howard C. Ansel, Loyd V. Allen and Nicholas G. 

Popovich. Ansels pharmaceutical dosage forms and 

drug delivery systems, 6 th d:268 

5.Bhagwan D. Rohera, Nilesh H. Parikh, Influence 

of plasticizer type and coat level on surelease film 

properties, Pharmaceutical development and 

technology, 2002, 7 (4),407-420. 

6.Isaac Ghebre-Shllassie pallets , A General 

overview. In pharmaceutical Pelletization 

technology; Ghebre-Shllassie, I. Ed.; Marcel Dakker, 

Inc.: Newyork, 1989; 37, 1-14. 

7.Ghebre-Shllassie, Olsen K.W, Fluid bed 

equipment pharmaceutical Pelletization technology, 

I. Ed.; Marcel Dakker, Inc.: Newyork, 1989; 37, 39- 

69. 

8.Ghebre-Shllassie, Johns, D.M. I. Ed ; Marcel 

Dakker, Solution and suspension layering. In 

pharmaceutical Pelletization technology; Newyork, 

1989; 37, 39-69. 

9.F. Norring Christensen, P. Bertelsen, Qualification 

and description of the Wurster – based fluid bed 

coating process Drug Development and industrial 

pharmacy, issue 5 April 1997, 23, 451- 463. 

10.Ozturk AG et al, Mechanism release from pellets 

coated with ethyl cellulose based films, Journal of 

control release 1990, 203- 213. 

11.Kesarin Busaranon et al, Comparison of UV 

spectrophotometric method and high performance 

liquid chromatography for the analysis of 

Flunarizine and its application for the dissolution 

test, Journal of Pharmaceutical and Biomedical 

Analysis 41 (2006) 158–164. 

12.Lachman L, Liberman HA The Theory and 

Practice of Industrial Pharmacy, 3 rd edition, 

Varghese Publishing House, Bombay, 1987, 430- 

456.

international journal of advances in pharmaceutical research

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?