issn: 0975-766x coden: ijptfi available online through ... · imatinib mesylate α-form2, 3 is a...

Senthil Periasamy Sengodan* et al. /International Journal Of Pharmacy&Technology

IJPT | Oct-2012 | Vol. 4 | Issue No.3 | 4749-4758 Page 4749

ISSN: 0975-766X CODEN: IJPTFI

Available Online through Research Article www.ijptonline.com

DESIGN AND EVALUATION OF IMATINIB MESYLATE MICROSPH ERES USING CHITOSAN AND HPMC K100

Nagesh.R.Sandhu1, Senthilkumar. K. Loganathan1, Senthil Periasamy Sengodan*2

1Padmavathi College of Pharmacy, Dharmapuri, Tamilnadu, India 2The Erode College of Pharmacy and Research,

Veppampalayam, Erode, Tamilnadu, India. Email: [email protected]

Received on 08-09-2012 Accepted on 22-09-2012

Abstract

Microencapsulation is one of the novel methods for retarding drug release from dosage forms and minimizing the

adverse effects thereby increasing the patient compliance. Microspheres form homogeneous, monolithic particles which

improve the treatment by providing localization of the drug at the site of action and by prolonging the drug release. The

objective of the present study was to formulate sustained release microspheres of Imatinib mesylate using Chitosan and

HPMC K100 as release retarding agent. The results of FTIR spectral and DSC studies showed that there was no

significant interaction between the drug and polymer. The maximum yield of the microspheres was found to be 86.58%

and the encapsulation efficiency was found to be 96.85%. The prepared microspheres released the drug completely

within 24 hours at lower drug to polymer ratio. At ratio of more than 1:4, the drug release was sustained over a period

of 24 hours. The microspheres were discrete, spherical and uniform in shape. The particle size was of the microspheres

was found to be 102.53µm. The prepared microspheres showed minor changes in particle size only under long term

stability study with no appreciable change in drug content proving good stability of the product conducted both in 0⁰C,

ambient and accelerated temperatures. The present study signifies the utility of microspheres in retarding the drug

release. This may in turn reduces the frequency of dosing, thereby improving the patient compliance.

Keywords: Chitosan, HPMC K100, Imatinib mesylate, Release Kinetics, Solvent Evaporation.



Introduction

Research and development, of drug-delivery systems are increasing at a rapid pace throughout the world. This global

trend will increase in the next decade as cuts in public health expenses require lower costs and higher effectiveness. To

meet this demand, many efficient drugs currently in use will be reformulated within release systems that can be value-

added for best possible molecular activity. Currently, microencapsulation techniques are most widely used in the

development and production of improved drug-delivery systems. These techniques frequently result in products

containing several variably coated particles1.

Imatinib mesylate (α form) is used to treat cancers and act by specifically inhibiting a certain enzymes of a

receptor tyrosine kinase and its characteristics of a particular cancer cell, rather than non specifically inhibiting and

killing all rapidly dividing cells.

1.1 Materials and Method

Imatinib mesylate α-form2, 3 is a gift from Natco Pharma Limited. HPMC K 100 was obtained a gift sample

from micro labs Bangalore, Chitosan was obtained from Ajantha Pharma Mumbai as a gift sample. Dichloromethane,

methanol, is the analytical range from SD fine Chemicals Mumbai.

1.2 Method of preparation

Imatinib mesylate (α form) were prepared by solvent evaporation techniques4, 5. A typical procedure was as

follows: Different amounts of Chitosan, HPMC K100 were dissolved in 8.5 ml of acetone separately by using a

magnetic stirrer. The core material Imatinib mesylate was added to the polymer solution and mixed for 15 minutes. The

resulting dispersion was added in a thin stream to a mixture of 90ml light liquid paraffin and 10ml n-Hexane contained

in a 250 ml beaker, while stirring at 900 rpm using a mechanical stirrer. Stirring was continued for 3 hrs until the

acetone evaporated completely. The microspheres formed were filtered using Whattman no.1 filter paper. The residue

was washed 4-5 times with 50 ml portions of n-Hexane. The product was then dried at room temperature for 24 hrs and

subsequently stored in vaccum desiccators over fused calcium chloride. All the batches were prepared in the same

method[Table1].



Table-1: Formula for Microspheres Preparation.

Formulation code Drug(mg) Chitosan(mg) HPMC K100(mg)

SVF1 400 200 --

SVF2 400 400 --

SVF3 400 600 --

SVF4 400 800 --

SVF5 400 1000 --

SVF6 400 -- 200

SVF7 400 -- 400

SVF8 400 -- 600

SVF9 400 -- 800

SVF10 400 -- 1000

2. Evaluation of Microspheres:

2.1 Particle size determination6, 7, 8

Particle size was determined by using an optical microscope under regular polarized light, and the mean particle

size was calculated by measuring 50-100 particles with a help of a calibrated ocular microscope.

2.2 Tapped density

The sample of specified quantity of granules was carefully introduced into a 20 ml graduated cylinder. The

cylinder was dropped at a two second intervals onto a wood surface 100 times from a height of 1 inch. It was calculated

by using an equation below.

Df = M/Vp

Df = Bulk density

M = Weight of samples in grams

Vp = Final tapped volumes of granules in cm3


IJPT | Oct-2012 | Vol. 4 | Issue No.3 | 4749-4758 752

2.3 Angle of repose

The angle of repose (θ) i.e., flow property of the microspheres which measures the resistance to particle flow

was calculated as

tan(θ)=2H/D

where,

2H/D is the surface area of the free standing height of the microspheres heap that is formed after making the

microspheres flow from the glass funnel.

2.4 Carr’s index

The percentage compressibility of microspheres was calculated according to equation given below,

% Compressibility= DO-Df/DO × 100

DO = Tapped Density

Df = Bulk Density

2.5 Hausuers ratio

The percentage compressibility of microspheres was calculate according to equation given below,

% Compressibility= DO/ Df

DO = Tapped Density

Df = Bulk Density

2.6 Drug loading %9

50 mg of microspheres were treated with 50 ml of phosphate buffer (pH 7.4), in 100 ml amber colored vial with

stirring at 250 rpm. The temperature was maintained at 37 ± 0.2º C. At the end of two hours it was filtered, and the

filtrate was analyzed photometrically at 230 nm using U.V. Visible spectrophotometer (Shimadzu, Japan). Drug

loading efficiency was calculated as:

Drug encapsulation (%) = (Actual drug concentration / Theoretical drug concentration) × 100

Drug loading (%) = (Weight of drug / Weight of microspheres) × 100

2.7 Percentage yield10

The prepared microspheres with a size range of were collected and weighed from different formulations. The

measured weight was divided by the total amount of all non-volatile components which were used for the preparation

of the microspheres.



% Yield = (Actual weight of product / Total Weight of excipients and drug) × 100

2.8 Differential scanning colorimetry (DSC)11

Thermograms were obtained by using a TGA Q200 V24.4 analyzer at a heating rate 50ºC /min over a

temperature range of 0 to 250°C. The sample was hermetically sealed in an aluminum crucible. Nitrogen gas was

purged at the rate of 100 ml/min for maintaining inert atmospheres.

2.9 In vitro dissolution studies12, 13

The drug release rate from prepared microspheres was carried out using the USP type II (Electro Lab.)

dissolution paddle assembly. A weighed amount of microspheres equivalent to 100 mg drug were dispersed in 900 ml

of 0.1N HCl for the first 2 hrs and the remaining pH 7.4 maintained at 32 ± 0.5°C and stirred at 100 rpm. 5 ml sample

was withdrawn at predetermined intervals and filtered and equal volume of dissolution medium was replaced in the

vessel after each withdrawal to maintain sink condition. The collected samples were suitably diluted with pH 7.4 and

analyzed spectrophotometrically at 230 nm to determine the concentration of drug present in the dissolution medium.

2.10 In vitro drug release kinetic studies14, 15

Kinetic model had described drug dissolution from solid dosage form where the dissolved amount of drug is a

function of test time. The exact mechanism of Imatinib Mesylate release from the microsphere was further studied by

kinetic models. The drug release data was analyzed by zero order, first order, Higuchi, Korsmeyer Peppa’s models. The

criteria for selecting the most appropriate model were chosen on the basis of goodness of fit test.

2.11 Stability study16, 17

The stability protocol was designed based on the ICH guidelines. The microspheres formulations chosen were

stored at 30⁰C ± 2°C and 65 ± 5%RH for a period of 3 months and at 40⁰C ± 2°C and 75 ± 5% RH for a period of 3

months. The stored samples were tested for their drug content and for any physical change. The testing was carried out

at 0, 1, 2, 3 months for accelerated storage condition and for long-term storage condition.

3. Result

3.1 Particle Shape

The shape and surface morphology of imatinib mesylate microspheres were observed by SEM photograph and

Optical Microscopic photograph shows in. Fig 2 and Fig 5. The obtained microcapsules are round to sphere in shape.

Senthil Periasamy Sengodan

IJPT | Oct-2012 | Vol. 4 | Issue No.3 | 4749-

Fig: 2 Scanning electron microscope of optimized formulation

Fig: 5 Optical microscopic Photo of optimized formulation

3.2 Drug polymer interaction studies

Drug-polymer interactions were studied by FT

mesylate, chitosan and HPMC K100 and physical mixture of drug and polymers (1:1). Samples were prepared in KBr

disks (2 mg sample in 200 mg KBr) with a hydrostatic press at a force of 5.2

was 400–4000 cm-1 and the resolution was 4


-4758

Scanning electron microscope of optimized formulation

microscopic Photo of optimized formulation.

polymer interactions were studied by FT-IR spectroscopy. The spectra were recorded for Imatinib

and HPMC K100 and physical mixture of drug and polymers (1:1). Samples were prepared in KBr

disks (2 mg sample in 200 mg KBr) with a hydrostatic press at a force of 5.2 τ cm-2 for 3 minutes.

and the resolution was 4 cm-1.

et al. /International Journal Of Pharmacy&Technology

Page 4754

Scanning electron microscope of optimized formulation.

IR spectroscopy. The spectra were recorded for Imatinib

and HPMC K100 and physical mixture of drug and polymers (1:1). Samples were prepared in KBr

2 for 3 minutes. The scanning range



3.3 Micromeritic properties

The average particle size of the microspheres was determined by using optical microscope. The flow properties

and packing properties were investigated by measuring the angle of repose, tapped density and bulk density [table: 2].

Table-2: Physical Evaluation of Microspheres.

Formulation

code

Particle

Size(µm)

Angle of

Repose(θ)

Bulk Density

(gm/cm)

Tapped Density

(gm/cm)

Carr's

Index

Hausner’s

Ratio

SVF1 93.68+2.56 22.12 ± 0.639 0.800 ± 0.10 0.974+0.041 17.75±3.972 1.22±0.065

SVF2 99.97+1.16 23.42 ± 0.08 0.785 ± 0.02 0.988+0.01 19.88±2.763 1.26±0.055

SVF3 96.48+3.26 22.05 ±0.509 0.828 ± 0.02 1.00+0.030 17.99±0.935 1.22±0.01

SVF4 102.53+0.86 22.310 ± 1.20 0.813 ± 0.02 1.01+0.008 20.20±3.252 1.25±0.051

SVF5 97.87+1.92 24.05 ± 0.39 0.800 ± 0.05 0.991+0.002 19.29±0.473 1.24±0.005

SVF6 99.30+0.45 23.48 ± 1.44 0.804 ± 0.03 0.983+0.006 18.20±3.491 1.22±0.051

SVF7 102.01+0.77 22.88 ± 1.55 0.820 ± 0.08 0.992+0.002 17.34±0.734 1.21±0.01

SVF8 97.96+1.59 25.15 ± 0.46 0.818 ± 0.08 1.026+0.004 20.27±0.470 1.25±0.005

SVF9 97.91+0.38 24.19⁰±0.60 0.822 ± 0.08 1.02+0.007 19.41±1.341 1.24±0.02

SVF10 98.17+1.22 23.41⁰±0.12 0.819 ± 0.01 1.032+0.008 20.60±1.981 1.26±0.03

All the values are mean (n =3) ±SEM

3.4 Drug entrapment

Accurately weighed microspheres equivalent to 100mg of drug was suspended in 25 ml of methanol and

sonicated for 3 minutes. The solution was then filtered, diluted suitably and analyzed for drug content

spectrophotometrically at 230 nm. The percentage drug entrapment was calculated as follows and shown in table: 3.

% Drug Entrapment = Practical drug loading/ Theoretical drug loading X 100



Table-3: Evaluation of Microspheres.

Formulation code % Yield (%) Drug Content

(in25mg)

SVF1 81.99+0.635 22.33+0.854

SVF2 85.28+0.393 22.05+0.684

SVF3 83.35+1.606 22.47+1.070

SVF4 86.58+1.056 21.65+0.219

SVF5 84.56+1.650 22.62+0.262

SVF6 84.41+1.123 22.72+0.341

SVF7 85.29+1.012 21.94+0.332

SVF8 86.12+0.624 21.49+0.162

SVF9 85.13+1.572 21.68+0.121

SVF10 85.79+0.752 21.71+0.287

All the values are mean (n =3) ±SEM

3.5 Dissolution studies

Dissolution test was performed in USP XXIII dissolution test apparatus by paddle method.The dissolution

media used was 900 ml of 0.1N HCl for first 2hrs and remaining time 900

32 ± 0.5°C and rotated at 100 rpm. Aliquots samples were withdrawn at specified time intervals and replaced with

same volume of fresh media filtered and analyzed spectrophotometrically (Shimadzu

drug release [table: 3] [Fig:1].

Fig: 1


-4758

Drug Content

(in25mg)

Entrapment Efficiency

(%w/w)

Cum.%

Release

22.33+0.854 82.79+0.525 98.70+0.477

22.05+0.684 84.77+0.349 99.48+0.352

22.47+1.070 86.01+1.190 99.10+0.264

21.65+0.219 96.85+0.064 99.26+0.308

22.62+0.262 88.09+1.290 98.76+0.201

22.72+0.341 83.47+1.020 98.16+0.438

21.94+0.332 83.01+0.696 98.72+0.338

21.49+0.162 83.93+0.544 98.55+0.443

21.68+0.121 87.51+0.876 99.22+0.189

21.71+0.287 82.62+0.640 98.89+0.411


ml of 0.1N HCl for first 2hrs and remaining time 900 ml of phosphate buffer pH 7.4 maintained at

otated at 100 rpm. Aliquots samples were withdrawn at specified time intervals and replaced with

filtered and analyzed spectrophotometrically (Shimadzu Japan

Fig: 1 Cumulative % Drug Release.


Page 4756

R² Value ‘n’ value

98.70+0.477 0.992 0.69

99.48+0.352 0.994 0.689

99.10+0.264 0.991 0.705

99.26+0.308 0.994 0.699

98.76+0.201 0.994 0.658

98.16+0.438 0.992 0.716

98.72+0.338 0.992 0.685

98.55+0.443 0.992 0.648

99.22+0.189 0.991 0.662

98.89+0.411 0.995 0.666


ml of phosphate buffer pH 7.4 maintained at

otated at 100 rpm. Aliquots samples were withdrawn at specified time intervals and replaced with

Japan) at 230 nm for cumulative



3.6 Stability Studies Stability study was carried out for the SVF4 formulation by exposing it to different temperature

temperature and 40°C for 3 months. The sample was analyzed for drug content at the regular intervals. It was found

that no remarkable change in the drug content of SVF4 formulation. This indicates that SVF4 was stable at the above

temperature. SEM Analysis was also done for the opti

Fig-:3 scanning electron microscope of optimized

Formulation [Stored at 40oC].

Conclusion

An emulsion solvent evaporation technique has been successfully employed to produce Imatinib Meyslate

loaded Chitosan and HPMC K100 microspheres with maximum drug encapsulation and desirable release profile. The

formulation variable drug-polymer ratio exerted a significant influence on the drug encapsulation. The present study

signifies the utility of microspheres in retarding the drug release. This may in turn reduces the frequency of dosing,

thereby improving the patient compliance.

Reference

1. K.Shekhar et.al., A review on microencapsulation

2. www.drugs.com

3. www.drugbank.com

4. K.P.R.Chowdary, et al.,”Preparation and evaluation of mucoadhesive

olibanum resin for controlled release, J


-4758

Stability study was carried out for the SVF4 formulation by exposing it to different temperature

months. The sample was analyzed for drug content at the regular intervals. It was found


temperature. SEM Analysis was also done for the optimised (SVF4) formulation [Fig: 3 and Fig:

3 scanning electron microscope of optimized Fig-4: Scanning electron microscope of optimized

Formulation [stored at 0


and HPMC K100 microspheres with maximum drug encapsulation and desirable release profile. The

polymer ratio exerted a significant influence on the drug encapsulation. The present study

arding the drug release. This may in turn reduces the frequency of dosing,

A review on microencapsulation, Int J Pharm Sci Rev Res. 2010; 5: 58

Preparation and evaluation of mucoadhesive microcapsules

J Pharm. Res. 2011, 4: 3859-3861.


Page 4757

Stability study was carried out for the SVF4 formulation by exposing it to different temperature 0°C, Ambient

months. The sample was analyzed for drug content at the regular intervals. It was found


and Fig: 4].

Scanning electron microscope of optimized

[stored at 0oC].


and HPMC K100 microspheres with maximum drug encapsulation and desirable release profile. The

polymer ratio exerted a significant influence on the drug encapsulation. The present study

arding the drug release. This may in turn reduces the frequency of dosing,

58-62.

microcapsules of diclofenac employing



5. JC Price, et.al., Evaluation of enteric matrix microspheres prepared by emulsion solvent evaporation using

scanning electron microscopy. J Microencap. 2004, 2: 47 - 57.

6. Alferd Martin, Micromeritics, in “Physical Pharmacy”, 4th Edition, Lippincott Williams & Wilkins; 2001, 427-

429.

7. VS Subramanyam, Micromeritics in “Physical Pharmaceutics”, 2nd Edition,; Vallabh Prakashan - Delhi; 2000,

180-210.

8. S.P.Senthil, et.al., “Preparation and In-Vitro evaluation of Abacavir Sulphate loaded microspheres cross-linked by

different concentrations of glutaraldehyde”, Res J Pharm Technol. 2010, 3: 1-4.

9. S. S. Bansode, et.al., Microencapsulation: A review, Int J Pharm Sci Rev Res. 2010 1, 38-43

10. Manish P Patel, et.al., Designing and evaluation of microspheres of verapamil hydrochloride effect of methocel.

Res J Pharm Dos Form Tech. 2009; 1: 22-28.

11. Harsh Bansal, et.al., Microsphere: methods of preparation and applications; a comperative study. Int J Pharm Sci

Rev Res. 2011; 10: 69-78.

12. GD Gupta, et.al., Gastroretentive Floating Microspheres of Silymarin: Preparation and in-vitro Evaluation. Trop J

Pharm Res. 2010; 9: 59-66.

13. SY Vohra,et.al., Development and characterization of Stavudine microspheres prepared using different polymers.

J Pharm Res.2009; 2: 953-7.

14. Higuchi T. Mechanism of rate of sustained action medication, J Pharm Sci. 1963; 52: 1145-1149.

15. Peppas NA, et.al., A simple equation for the description of solute release III, Coupling of diffusion and relaxation,

Int J Pharm. 1989; 57:169–172.

16. Atul Kumar Gupta,et.al., Microsphere: methods of preparation and applications; a comperative study, Int J

Pharm Sci Rev Res 2011; 10: 69-78.

17. www.ich.org

Corresponding Author:

S.P.Senthil*,

Email: [email protected]

issn: 0975-766x coden: ijptfi available online through ... · imatinib mesylate α-form2, 3 is a...

Documents