FORMULATION DEVELOPMENT AND IN VITRO EVALUATION OF RAMIPRIL MICROPELLETS

www.wjpr.net ₇₆

FORMULATION DEVELOPMENT AND IN-VITRO EVALUATION OF

RAMIPRIL MICROPELLETS

*

Raju Nuka1, Appa Rao Potu2, Raghu Nandan. N3

Department of Pharmaceutics, Balaji Institute of Pharmaceutical Sciences, Warangal, India

ABSTRACT

The present study was undertaken with an aim to develop immediate

release micro pellets of Ramipril by powder layering technique by

using various supper disintegrating agents sodium starch

clycolate(SSG), cross carmellose sodium(CCS) and cross povidone

(CP). Ramipril which is a antihypertensive drug and is one of the

most widely used drugs for treating mild and moderate hypertension

and congestive heart failure .Ramipril has a long biological half life

(3-16 hrs), and along with elimination half –life ( 9-18 hours )

suggests its immediate action for treating hypertension . More

particularly, the present investigation was directed for stabilizing the

Ramipril against decomposition into degradation products, namely,

Ramipril-DKP(diketopiperzine) and Ramipril-diacid during

formulation and storage conditions. The prepared micropellets were

charecterized for their bulk density ,tapped density , carr’s index and Hausner ratio and

in-vitro drug release studies. The particle size and moRamiprilhology of the pellet were

evaluated by using sieve analysis and Scanning electron microscopy (SEM). Drug –

excipient compatability studies were investigated by Fourier –transform infrared

spectroscopy(FTIR). In-vitro drug release studies of the micro pellets revealed immediate

drug release behaviour. Nine formulations were prepared of which pellets containing SSG (

FR 8) (4 % ) exhibited maximum drug release in 15 minutes i.e 98.81 % compared to other

formulations.

Keywords: Ramipril, micropellet, diketopiperzines, immediate release.

Volume 2, Issue 1, 76-87. Research Article ISSN 2277 – 7105

Article Received on 01 November 2012,

Revised on 18 November 2012, Accepted on 03 December 2012

*Correspondence for Author:

* Raju Nuka

Department of Pharmaceutics,

Balaji Institute of

Pharmaceutical Sciences,

Warangal, A.P., India

www.wjpr.net ₇₇ INTRODUCTION

Hypertension, commonly referred to as “high blood pressure”, is a medical condition and is

one of the common disorder affecting people worldwide. ACE inhibitors are commonly

prescribed drugs for treating hypertension either alone or in combination with diuretics.

Conventional immediate release drug delivery system are based on single or multiple-unit

reservoir or matrix system, which are designed to provide immediate drug levels in short

period of time. Immediate release drug delivery is desirable for drugs having long biological

half life, high bioavailability, lower clearance and lower elimination half life(ref).

RAMIPRIL is a prodrug and is converted to the active metabolite by liver esterase enzymes

and is an angiotensin converting enzyme (ACE) inhibitor, used to treat hypertension and

congestive heart failure. Its long biological Half life (3-16hours) and its dose (10 mg / day)

and long elimination phase (9-18hours) suggest it’s immediate action. The maintenance of a

constant plasma level of a cardiovascular drug is important in ensuring the desired

therapeutic response.1

As RAMIPRIL needs special care during manufacturing stage as it it has a tendency for

decomposition due to the physical stress associated with various oprations stages involved in

manufacturing processes leading to increase in the rate the decomposition. The factors that

influence the stability of ramipril formulations are mechanical stress, compression,

manufacturing processes, excipients, storage conditions, heat and moisture2,3,4. Micropellets,

gives more stability from compression and other stress conditions during formulation and

storage conditions. Moreover, pellets being multi-unit particulate dosage forms, can offer

some additional advantages such as easy dispersion in GI tract, increased drug

absoRamipriltion, and minimum poptential for local irritation of the drug5,6. The

micropellets can be filled into hard gelatin capsules or be compressed into tablets. The

compression of multiparticulates into tablets is becoming more popular, because of no

problems of tampering7,8,9. So, this study focused on the development of immediate release

tablets containing pellets.

MATERIALS & METHODS

Ramipril was a gift sample from Hetero labs, India, .SSG was gift sample from sigma

chemicals, India, CCS and CP were procured from Unique labs, India. HPMC -5 was

www.wjpr.net ₇₈ Preparation of Micro Pellets

The RAMIPRIL micro pellets were prepared by powder layering technique. Non-pareil seeds

were taken into the coating pan and coated with drug and binder solution along with supper

disintegrating agents with a spray rate of 4.32 gm/min /kg. The prepared pellets were dried at

45 0 c for 8 hrs in a stainless steel tray drier. After completion of drying process, the

micro-pellets were passed through sifter to remove the lumped micro-pellets and subsequently were coated

with sub-coating solution (HPMC -5).The sub-coating solution was sprayed through nozzle

on pellets along with continuous flow of warm air to dry the coat as soon as it forms for

uniform coating. This process was continued till minimum weight gain of pellets was

achieved.

EVALUATION OF PELLETS Bulk Density

The bulk density of each formulation was then obtained by dividing the weight of sample in

grams by the final volume in cm3 of the sample contained in the cylinder. It was calculated by

using equation given below:

Df = M /Vp Where, Df = bulk density

M = weight of sample in grams

Vp = final volume of powder in cm3

Tapped Density

Tapped density is determined by placing a graduated cylinder containing known mass of

blends on a mechanical tapped apparatus, which is operated for a fixed number of taps until

the powder bed volume has reached a minimum volume. Using the weight of the drug in the

cylinder and this minimum volume, the tapped density may be computed.

Tapped Density = Weight of Blends /Tapped Volume of Blends

Carr’s Index

Carr’s Index is calculated using the values of the bulk density and tapped density with th

help of the following equation.

www.wjpr.net ₇₉ Table no.1:Compressibility Index and flow property

Compressibility

index

Type of flow

≤10 Excellent

11-15 Good

16-20 Fair

21-25 Passable

26-31 Poor

32-37 Very poor

>38 very very poor

Angle of Repose

The manner in which stresses are transmitted through a bed and beds response to applied

stress reflected in the various angles of friction and response. The most commonly used of

these is angles of response. The method used to find the angles of response is to pour the

powder in a conical heap on a level flat surface and measure the inclined angle with the

horizontal pile.

Tan θ =

Where h = Height of the heap.

R = Radius of the heap.

Table No.2: Angle of repose and flow property

Hausner’s Ratio

Haussner’s ratio was determined as the ratio between the tapped density to that of the bulk

density.

Hausner’s ratio =Tapped density / Bulk Density

Angle of repose Type of flow

<20 Excellent

20-30 Good

30-34 Passable

www.wjpr.net ₈₀ Table No.3: Hausner’s Ratio and flow property

Hausner’s ratio Type of flow

1.00-1.11 Excellent

1.12-1.18 Good

1.19-1.25 Fair

1.26-1.34 Passable

1.35-1.45 Poor

1.46-1.59 Very poor

>1.60 Very very poor

The formulated micro-pellets were evaluated for compatibility, particle size and shape

analysis using scanning electron microscopy,bulk density ,tapped density angle of repose and

carr’s index.

In-vitro dissolution Studies: The release of the drug from the developed formulations was

determined using the USP -1 dissolution apparatus–1(Basket).Capsules containing

micropellets equivalent to 10 mg of RAMIPRIL in beaker containing 900 ml of 0.1 HCL

maintained at 37+ 0.5 and 100 Ramiprilm. 2ml of aliquot were withdrawn at specified

intervals and after suitable , assayed by Shimadzu Uv-Vis Spectrophoto meter at 208 nm .

The FR8 (RAMIPRIL + SSG) showed maximum drug release of 98.84 % in 15 minutes.

FT-IR study

The Fourier transform –infrared spectra of Ramipril, mixures Ramipril and SSG, Ramipril

and CP , Ramipril and CCS, They showed the characteristic peaks of individual Ramipril ,

excipients and their mixtures. The spectra showed no extra peakes indicating that there is no

interaction between RAMIPRIL, excipients and their mixture.

Scanning electron microscope: The shape and surface characteristics were determined by scanning electron microscopy. SEM was performed using Hitachi (MODEL :S-3400 N,

www.wjpr.net ₈₁ Accelerated Stability study of the optimized formulation

Formulation were stored at various temperature viz.250C/60% RH,30oC/65%RH and

40oC/75 %RH as per ICH guidlines and various physicochemical parameter (apperence ,

percentage drug content and release profile ) were monitored periodically for 3 months10 .

RESULTS AND DISCUSSIONS

The present study was undertaken to formulate Ramipril immediate release(IR) micro pellets

.The study involved,formulation development along with evaluation of pellets for the

optimized one . Finally immediate release pellets were evaluated by in-vitro methods for drug

release, and its mechanism, size and surface moRamiprilhology and stability assessment.

Calibration Curve of Ramipril

The study started with the construction of standard calibration curve of Ramipril. The

scanning of the volumetric solution of Ramipril in the ultraviolet range against 0.1 N HCl

determined the max of absorbance is 208 nm.

Table No.4:Calibration curve of Ramipril Concentration Abs

2 0.199

4 0.34

6 0.486

8 0.626

10 0.769

12 0.89

The standard graph of Ramipril in 0.1N HCl was plotted by taking concentration ranging

from 2 to 12 µg/ml and showed good linearity with R2 value of 0.9993, which suggests that it

obeys the Beer-Lamberts law.

www.wjpr.net ₈₂ FORMULATION STUDIES

The contents showed in the table are weighed accurately sieved thoroughly through sieve 100.non pareil seeds were taken into the coating pan and coated with drug and binder solution

along with super disintegrating agents (CCS,CP,SSG) with a spray rate of 4.32

gm/min/kg.The second stage in the preparation of pellets includes drying. The stage 1 pellets

were dried at 45º C for 8 hrs in a SS Tray drier. After completion of drying process moisture

content were checked for moisture content and found to be below 1%. The dried pellets

were passed through sifter to remove the lumped pellets.This stage 3 process includes seal

coating. In this, in a clean and dry vessel HPMC E5 was taken and iso propyl alcohol was

added and stirred the solution to form a clear colloidal sub coating solution. The coating pan

was charged in with dried pellets. The above coating solution was sprayed through nozzle on

pellets along with continuous flow of warm air to dry the coat as soon as it forms for uniform

coating. The coating process was continued till minimum weight gain of coated pellets is

achieved.

Table No.5: Composition of Ramipril Micro Pellets

Ingredients F1 (2%) F2 (4%) F3 (6%) F4 (2%) F5 (4%) F6 (6) F7 (2%) F8 (4%) F9 (6%)

Ramipril 10 10 10 10 10 10 10 10 10

Micro pellets (non-pearl seeds)

82 80 78 82 80 78 82 80 78

PVPK 30

(4%)

4 4 4 4 4 4 4 4 4

Talc (1%) 1 1 1 1 1 1 1 1 1

Cp 2 4 6 - - - -

CCS - - - 2 4 6 - - -

SSG - - - 2 4 6

HPMC E15 1 1 1 1 1 1 1 1 1

Total capsule weight

100 100 100 100 100 100 100 100 100

Table No.6: characteristics of Pellets

Name of

Formulation

www.wjpr.net ₈₃

CCS3% 18.82º 0.66 0.673 1.93 1.01

CP1% CP2% CP3% 17.9o 18.8º 18º 0.631 0.592 0.648 0.652 0.604 0.661 3.22 1.98 1.966 1.033 1.02 1.02 SSG1% SSG2% SSG3% 20.8o 19.3º 21º 0.368 0.226 0.656 0.375 0.230 0.670 1.866 1.7391 2.81 1.019 1.017 1.028 Dissolution profile:

Table No.7: Cumulative percent drug release from pellets:

0.1N HCL %Drug Release

5min 10min 15min

FR1 56.41% 95.79% 97.06%

FR2 82.34% 97.29 97.52%

FR3 78.95% 96.24% 96.82

FR4 71.48% 88.53% 95.66%

FR5 76.27% 95.19% 96.47%

FR6 53.72% 97.76% 97.87%

FR7 49.40% 96.01 96.12

FR8 45.66 98.69 98.81

FR9 41.58 81.99 98.34

www.wjpr.net ₈₄ Fig :3 Cumulative percent drug release from immediate release micropellets

Accelerated Stability study of the optimized batch

The selected formulations were subjected for accelerated stability studies as per ICH

guidelines .There were no changes in appearance and percentage drug content of pellets

stored at different temperatures for drug remaining vs. Time at 250C/60% RH , 30oC/65%RH

and 40oC/75 %RH. All the parameters were within the limit after 90 days.

RAMIPRIL PURE DRUG

www.wjpr.net ₈₅ Fig: 5 RAMIPRIL + CROSS POVIDONE :

Fig : 6 RAMIPRIL+CROSSCARMELLOSE SODIUM:

www.wjpr.net ₈₆ SCANNING ELECTRON MICROSCOPY

Fig : 8 scanning electron micrograph of developed pellets .

Fig: 9 SEM photomicrograph of Ramipril micropellets in spherical shape.

www.wjpr.net ₈₇ CONCLUSION

From the present study,it was concluded that immediate release Ramipril micro pellets were

prepared by using various supper disintegrating agents in order to improve dissolution of the

drug and hence improve patient compliance and effective therapy. Therefore, it can

concluded that from our results,SSG showed better dissolution properties then that of CP and

CCS .

REFERENCES

1. Rang HP, Dale MM, Pharmacology, 4th edition, Churchill living stone, NY, 1999, 375.

2. Koytchchev R, Ozalp Y , Erenmemisoglu A, vander Meer MJ , alphan RS ,effect of the

combination of lisonopril and hydrochlorothiazide on the bioequivalence of tablet

formulations , Arzneimittelforschung. Asian jps, 2004: 54(9a); 605-10

3.Stabilized indivudially coated Ramipril particles, compostions and methods,

Wo2006050533, 2006, 11-16.

4. St1abilized Ramipril compositions and methods of making ,wo2006052968, 2006 11-16 .

5.M.jalal ,H.J .malinowski ,and W.E .smith , tablet granulations composed of spherical

shaped particals , j.pharm .sci.,1972,61;1466-790

6.Parikh ,B,M .alternatives for processing spherical granules ,paper presented at

inteRamiprilhex usa ,newyork ,ny ,usa,1990

7. Bodmeier R. Tableting of coated pellets. Eur. J. Pharm. Biopharm. 1997; 43:1,8.

8. Celik M. Compaction of multiparticulate oral dosage forms. In I. Ghebre-Sellasie (ed.),

Multiparticulate oral drug delivery. Marcel Dekker, New York, 1994.

9. Juslin M, Turakka L, Puumalainen P. Controlled release tablets. Pharm. Ind. 1980;

42:829,832

10. paulo costa . and jose manuel sausalobe .,modelling and compression of dissolution