Formulation and Evaluation of Aceclofenac-loaded Nanoparticles by Solvent

Evaporation Method

Abstract

Nanoparticles have applications in the formulation of poorly water soluble drugs to improve

their bioavailability. Preparation and evaluation aceclofenac-loaded nanoparticles by solvent

evaporation method to enhance solubility and bioavailability were the primary aim of the

present investigation. Nanoparticles of aceclofenac, a BCS class II drug were prepared by

solvent evaporation technique and characterized using Fourier transform infrared

spectroscopy, particle size & zeta potential, scanning electron microscopy and drug release

studies in vitro. Data from the Fourier-transform infrared spectroscopy showed no interaction

between drug and the polymers. Scanning electron microscopy images indicated that

nanoparticles were spherical in shape. Water solubility of drug-loaded nanoparticles was

increased as compared to the pure drug and showed improved dissolution profile, which

indicated that nanoprecipitation, was simple and precise. This laboratory scale method as well

as this approach could be employed for solubility and bioavailability improvement of

aceclofenac.

Keywords: Nanoparticles, Aceclofenac, Solvent evaporation method, Scanning electron

microscopy.

Introduction

Advanced drug delivery systems have numerous advantages over conventional multi dose

therapy. Much research effort in developing such drug delivery systems has been focused on

controlled release and sustained release dosage forms. Now a day effort is being made to

deliver the drug in such a manner so as to get optimum benefits [1, 2]. There are numerous

strategies in delivering therapeutic agent to the target site in a sustained release fashion. One

such strategy is using nanoparticles as drug carrier [3, 4]. The major nanoparticulate drug

delivery system is liposomes and polymeric nanoparticles have particular advantage for site-

specific drug delivery and to enhance the dissolution rate along with bioavailability of poorly

water soluble drugs [5]. Formation of drug-loaded nanoparticles is actually a very promising

approach. Particle size reduction to the nanometre range can be achieved using various

techniques and these techniques have been extensively described [6]. Poor solubility and low

dissolution rate of Biopharmaceutical Classification System (BCS) class II drugs in the

aqueous gastrointestinal fluids often causes insufficient bioavailability and this can only be

enhanced by increasing the solubility and dissolution rate by using various novel techniques

[7]. Some of the techniques employed to improve drug dissolution rate are solid dispersion,

inclusion complex formation, microparticles and nanoparticles. Nanoparticles are colloidal

particles ranging from 10 to 1000 nm, in which the active principles (drug or biologically

active material) are dissolved, entrapped [8]. And these are of different types include,

nanospheres, nanocapsules, dendrimers, solid-lipid nanoparticle, polymeric micelles and

liposomes. With the development in nanotechnology, it is now possible to produce drug

nanoparticles that can be utilized in a variety of innovative ways. New drug delivery

pathways can now be used to increase drug efficacy and reduce side effects [9]. Solid-lipid

nanoparticles are at the rapidly developing field of nanotechnology with several potential

applications in the clinical medicine and research. Nanoparticles are receiving considerable

attention for the delivery of therapeutic drugs. Depending on the physicochemical

characteristics of a drug, it is now possible to choose the best method of preparation with the

best polymer to achieve an efficient entrapment of the drug [10]. Different methods for the

preparation of nanoparticles are available, which include, solvent evaporation,

nanoprecipitation, emulsification/solvent diffusion, salting out, dialysis, supercritical fluid

technology and rapid expansion of supercritical solution, rapid expansion of supercritical

solution into liquid solvent. Aceclofenac, [2-[[2-[2- [(2, 6-dichloro phenyl) amino] phenyl]

acetyl] oxy] acetic acid], is a NSAID of the phenyl acetic acid group which is structurally

related to diclofenac. Aceclofenac acts with preferential selective cyclooxygenase-2 (COX-2)

inhibition after conversion into active metabolite [11-13]. Which could be extremely

beneficial in ocular inflammation? Aceclofenac possess its action by inhibiting the secretion

of tumor necrosis factor (TNF-α) and interleukin-1. Moreover, aceclofenac possesses good

anti-inflammatory and analgesic activities and have better gastric tolerance in comparison

with other NSAIDs such as indomethacin and diclofenac. Aceclofenac is a BCS class II drug,

which has low solubility and high permeability [14]. Aceclofenac is not stable and gets easily

hydrolyzed in aqueous environment. Present work deals with the preparation and evaluation

of aceclofenac-loaded nanoparticles by solvent evaporation technique.

Materials and Methods

Aceclofenac was received as gift from and Ranbaxy research laboratotries (Gurgaon, India).

Ethyl cellulose, Chitosan, HPMC K100 was procured from Qualikems fine chem. Pvt Ltd

Vadodhara. Ethanol, polyvinyl alcohol, dichloromethane was purchased from CDH chemical

Pvt. Ltd. New Delhi. Dialysis membrane of Mol Wt cutoff 1200 was purchased from

Himedia Laboratory, Mumbai. Double distilled water was prepared freshly and used

whenever required. All other ingredients and chemicals used were of analytical grade.

Preformulation study

Preformulation is the first step in rationale development of any pharmaceutical dosage form

of a new drug. Preformulation study focuses on those physicochemical properties of the new

compound that can affect drug performance and development of an efficacious dosage form.

These preformulation investigations confirm that there are no significant barriers to the

compounds development. Melting point of aceclofenac was determined by open capillary

tube method. FTIR spectra of pure drugs, polymers used and blends were recorded on KBr

disk method using Brukers Alpha Spectrophotometer with IR solution software to confirm

the compatibility between drug and excipients. Sample powder was thoroughly mixed by

triturating with potassium bromide in a glass mortar with pestle and compressed into disks in

a hydraulic press (Techno search Instruments, India). FTIR spectra of all the samples were

recorded over a spectral region from 4700 to 400 cm-1 using 20 scans with 4 cm-1 resolution.

Determination of absorption maxima

A solution of containing the concentration 20μg/ml was prepared in 0.1N HCl. UV spectrum

was taken using Double beam UV/VIS spectrophotometer (UV-1700 Shimadzu Corporation,

Japan). The solution was scanned in the range of 200-400nm.

Preparation calibration curve

Accurately weighed 10 mg of drug was dissolved in 10 ml of 0.1N HCl solution in 10 ml of

volumetric flask separately. The resulted solution 1000µg/ml and from this solution 1 ml

pipette out and transfer into 10 ml volumetric flask and volume make up with 0.1N HCl

solution. Prepare suitable dilution to make it to a concentration range of 5-35μg/ml. The

spectrum of this solution was run in 200-400 nm range in U.V. spectrophotometer (UV-1700

Shimadzu Corporation, Japan). The absorbance of these solutions was measured at 274 nm

0.1N HCL as a blank. Linearity of standard curve was assessed from the square of correlation

coefficient (r2) which determined by least-square linear regression analysis.

Method of preparation

Nanoparticles prepared by polymers like chitosan, ethyl cellulose, hydroxyl propyl methyl

cellulose and polyvinyl alcohol by solvent evaporation method. Disperse phase consisting of

aceclofenac (300mg) and requisite quantity of polymers dissolved in 20 ml solvent

(dichloromethane) was slowly added to a definite amount of PVA in 100ml of aqueous

continuous phase. The reaction mixture was stirred at 1000 rpm for two- three hours on a

magnetic stirrer. The nanoparticles formed were collected by filtration through whatman filter

paper and dried in oven at 500C for 2 hours. The dried nanoparticles were stored in vaccum

desicater to ensure the removal of residual solvent [15] Table 1.

Table 1 Formulation of aceclofenac nanoparticles

Formulation

Code

INGREDIENTSAceclof

enac (mg)

Ethyl cellulose

(mg)

Chitosan

(mg)

HPMC K100 (mg)

Polyvinyl alcohol (%w/v)

Dichlro Methane

(ml)

Distilled water (ml)

F1 300 300 0.2 20 100F2 200 600 0.2 20 100F3 300 900 0.2 20 100F4 300 1200 0.2 20 100F5 300 300 0.2 20 100F6 300 600 0.2 20 100F7 300 900 0.2 20 100F8 300 1200 0.2 20 100F9 300 300 0.2 20 100F10 300 600 0.2 20 100F11 300 900 0.2 20 100F12 300 1200 0.2 20 100

Characterization of nanoparticles

Organoleptic properties of the nanoparticles like colour, odour and physical appearance were

observed visually and recorded. Practical yield was calculated using the Eqn., PY (%) =

amount of product obtained/amount of total solid used (polymer+drug)×100.

Drug content

Sample containing 100 mg equivalent aceclofenac nanoparticles are dissolved and the

volume is made upto 100ml with 0.1 N HCl. From the above solution 10 ml is pipette out and

made upto 100 ml with 0.1 N HCl. The Absorbance of resulting solution is determining at

λmax (274 nm) using UV spectrophotometer (UV-1700 Shimadzu Corporation, Japan) and

the drug content is estimated using 0.1 N HCl blank.

Drug entrapment

The various formulations of the aceclofenac nanoparticles were subjected for drug content.

10 mg of nanoparticles from all batches were accurately weighed and crushed. The powder of

nanoparticles were dissolved in 10 ml 0.1 N HCl and centrifuge at 1000 rpm. This

supernatant solution is than filtered through whatmann filter paper No. 44. After filtration,

from this solution 0.1 ml was taken out and diluted up to 10 ml with 0.1 N HCl. The

percentage drug entrapment was calculated using calibration curve method.

Measurement of mean particle size

The mean size of the nanoparticles was determined by Photo Correlation Spectroscopy (PCS)

on a submicron particle size analyzer (Horiba Instruments) at a scattering angle of 90°. A

sample (0.5mg) of the nanoparticles suspended in 5 ml of distilled water was used for the

measurement.

Determination of zeta potential

The zeta potential of the drug-loaded nanoparticles was measured on a zeta sizer (Horiba

Instruments) by determining the electrophoretic mobility in a micro electrophoresis flow cell.

All the samples were measured in water at 25°C in triplicate.

Shape and surface characterization of nanoparticles by scanning electron microscopy

(SEM)

Morphological evaluation of the selected nanoparticles formulation is carried out in scanning

electron microscope (SEM) (Hitachi X650, Tokyo, Japan).All samples are examined on a

brass stub using carbon double-sided tape. Powder samples are glued and mounted on metal

sample plates. The samples are gold coated (thickness ≈15–20 nm) with a sputter coater

(Fison Instruments, UK) using an electrical potential of 2.0kV at 25 mA for 10 min. An

excitation voltage of 20 kV was used in the experiments [16-19].

In-vitro release studies

The drug release rate from nanoparticles was passed out using the USP type II (Electro Lab.)

dissolution paddle instrument. A weighed amount of nanoparticles equivalent to 100 mg drug

were dispersed in 900 ml of 0.1 N HCI maintained at 37 ± 0.5°C and stirred at 55rpm. One

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 analyzed spectrophotometrically at 274 nm to determine the

concentration of drug present in the dissolution medium [20-24].

Mathematical treatment of in-vitro release data: The quantitative analysis of the qualities

got in dissolution/release tests is simpler when mathematical formulas that express the

dissolution comes about as an element of a portion of the measurement frames attributes are

utilized.

1. Zero-order kinetics: The pharmaceutical dosage frames following this profile release a

similar measure of medication by unit of time and it is the ideal method of medication release

keeping in mind the end goal to accomplish a pharmacological prolonged action. The

following relation can, in a simple way, express this model:

Qt = Qo + Ko t

where Qt is the amount of drug dissolved in time t, Qo is the initial amount of drug in the

solution (most times, Qo=0) and Ko is the zero order release constant.

2. First-order kinetics: The following relation expresses this model:

where Qt is the amount of drug dissolved in time t, Qo is the initial amount of drug in the

solution and K1 is the zero order release constant.

Along these lines a graphic of the decimal logarithm of the released measure of drug versus

time will be linear. The pharmaceutical dosage shapes following this dissolution profile, for

example, those containing water-solvent drugs in permeable frameworks, discharge drug in a

way that is corresponding to the measure of drug staying in its inside, in such way, that the

measure of drug released by unit of time reduce.

3. Higuchi model: Higuchi built up a few theoretical models to ponder the arrival of water-

solvent and low dissolvable medications in semi-strong or potentially strong grids.

Mathematical expressions were acquired for sedate particles scattered in a uniform grid

acting as the diffusion media. The simplified Higuchi model is expressed as:

Where Q is the amount of drug released in time t and KH is the Higuchi dissolution constant.

Higuchi model describes drug release as a diffusion process based in the Fick’s law, square

root time dependent. This relation can be utilized to portray the drug dissolution from a few

kinds of modified release pharmaceutical dosage structures, for example, transdermal systems

and mucoadhesivetablets with water-dissolvable drugs.

4. Korsmeyer-Peppas model: Korsmeyer et al. used a simple empirical equation to describe

general solute release behaviour from controlled release polymer matrices:

Where Mt/M is fraction of drug released, a is kinetic constant, t is release time and n is the

diffusional exponent for drug release. ’n’ is the slope value of log Mt/M versus log time

curve. Peppas stated that the above equation could adequately describe the release of solutes

from slabs, spheres, cylinders and discs, regardless of the release mechanism. Peppas used

this n value in order to characterize different release mechanisms, concluding for values for a

slab, of n =0.5 for fickian diffusion and higher values of n, between 0.5 and 1.0, or n =1.0, for

mass transfer following a non-fickian model. In case of a cylinder n =0.45 instead of 0.5, and

0.89 instead of 1.0. This equation can only be used in systems with a drug diffusion

coefficient fairly concentration independent. To the determination of the exponent n the

portion of the release curve where Mt/M < 0.6 should only be used. To use this equation it is

also necessary that release occurs in a one-dimensional way and that the system width-

thickness or length-thickness relation be at least 10. A modified form of this equation was

developed to accommodate the lag time (l) in the beginning of the drug release from the

pharmaceutical dosage form:

When there is the possibility of a burst effect, b, this equation becomes:

In the absence of lag time or burst effect, l and b value would be zero and only atn is used.

This mathematical model, also known as Power Law, has been used very frequently to

describe release from several different pharmaceutical modified release dosage forms.

Stability studies

The nanoparticle formulation was subjected to stability studies according to ICH guidelines

by storing at 250C/60% RH and 400C/75% RH for 60 days. These samples were analyzed and

checked for changes in physical appearance, drug content and entrapment efficiency, invitro

drug release studies at regular intervals. The formulation subjected for stability study was

stored in borosilicate container to avoid any interaction between the formulation and glass of

container.

Results and Discussion

Solubility of aceclofenac was freely soluble in methanol, DMSO, acetone and ethanol,

soluble in 0.1N HCL and 6.8 pH phosphate buffers, insoluble in water. The melting point of

aceclofenac was 154-156ºC and λ max of aceclofenac was found to be 274 nm by using U.V.

spectrophotometer (UV-1700 Shimadzu Corporation, Japan) in linearity range 5-35 µg/ml

Figure1. Partition coefficient of aceclofenac was found to be 1.85.

Figure 1Determination of λmax of aceclofenac

From the spectra of aceclofenac physical mixture of drug and selected ingredients it was

observed that all characteristic peaks of aceclofenac were present in the combination

spectrum, thus indicating compatibility between drug and selected ingredients. FTIR Spectra

shown in Figure 2 and 3.

Figure 2 FTIR spectra of pure aceclofenac

Figure 3 FTIR Spectra of aceclofenac nanoparticlePractical yield, drug content and EE were given in Table 2. Practical yield of the prepared

nanoparticles was in the range of 24.43±1.37 to 64.51±0.97%. The yield of nanoparticles

decreased with increasing the concentration of drug and polymer ratio, which might be due to

generation of stickiness by polymer. It was found that with increasing the amount of polymer,

the actual drug loading and EE increased. The EE was found to be in the range from

55.36±0.83 to 91.88±1.38 %. The drug content of nanoparticles was found to be in the range

of 84.56±1.27 to 97.20±1.46 %. It was observed that the drug content and encapsulation

efficiency depends on the concentration of polymer, solvent ratio and stirring rate. On the

basis of high yield, actual drug content and encapsulation efficiency batch F2, 6, 10 was

observed as optimized batch for the preparation of nanoparticles.

Table 2 Practical yield, drug loading and entrapment efficiency of nanoparticles

S. No.

F. Code

(%)Practical yield

(%)Drug

content

(%)Entrapment

efficiency1. F1 62.09±0.93 91.22±1.37 68.56±1.032. F2 43.61±1.65 94.01±1.41 75.96±1.143. F3 29.71±0.45 88.57±1.33 64.53±0.974. F4 24.43±1.37 85.88±2.29 67.84±1.02

5. F5 64.51±0.97 84.56±1.27 68.66±2.036. F6 41.51±2.62 97.20±1.46 91.88±1.387. F7 32.42±0.49 91.17±0.37 74.93±1.128. F8 25.06±1.38 91.34±1.37 55.36±0.839. F9 62.11±0.93 91.03±1.37 68.85±3.0310. F10 44.79±1.67 95.03±2.43 75.57±1.1311. F11 31.07±0.47 91.46±1.37 61.33±1.9212. F12 25.87±2.39 87.33±1.31 59.15±0.89

The nanoparticles were evaluated for in vitro dissolution studies in 0.1N HCl for 12 hours.

The results of in-vitro drug release revealed that the aceclofenac was released in a controlled

manner from F2, 6, 10 the formulations where formulation F6 showed maximum drug release

i.e. 98.07±0.73 % at the end of 12th hour. The results of release studies of formulations F2, 6,

10 are shown in Table 3 and Figure 4. The in vitro drug release data of the optimized

formulation F6 was subjected to goodness of fit test by linear regression analysis according

to zero order, first order kinetic equation, Higuchi’s and Korsmeyer’s models in order to

determine the mechanism of drug release. When the regression coefficient values of were

compared, it was observed that ‘r’ values of Peppas model was maximum i.e0.9924hence

indicating drug release from formulations was found to follow zero order kinetics Table 4 &

Figure 5-8.

Table 3 In-vitro drug release study of nanoparticlesS. No. Time in

hoursCumulative % Release

F2 F6 F101. 1 2.84±0.35 2.77±0.25 2.08±0.062. 2 12.32±2.05 17.05±0.71 10.65±0.153. 3 21.81±0.23 20.91±0.68 22.47±2.024. 4 26.95±0.26 29.57±0.33 32.03±0.465. 5 32.96±1.48 35.95±0.91 37.09±0.926. 6 37.39±1.55 42.96±1.14 43.55±0.947. 7 44.87±0.65 49.73±0.81 50.22±0.858. 8 52.41±0.93 57.59±1.16 58.46±1.119. 9 58.28±0.68 67.51±1.03 65.99±0.8510. 10 64.38±1.14 77.28±0.47 72.55±1.2111. 11 80.49±1.84 88.37±1.81 80.48±1.0112. 12 87.07±1.07 98.07±0.73 90.02±0.77

Figure 4 In-vitro drug release study of nanoparticlesTable 4 Regression analysis data of aceclofenac nanoparticle

Batch Zero Order First Order Higuchi Korsmeyer-Peppas

r² r² r² r²F5 0.9924 0.9371 0.9710 0.9413

Figure 5 Zero order release Kinetics

Figure 6 First order release kinetics

Figure 7 Higuchi release Kinetics

Figure 8Korsmeyer-Peppas release KineticsThe results of measurement of mean particle size of optimized formulation F6 of aceclofenac

nanoparticle was found 195 nm Figure 9. Results of zeta potential of optimized formulation

F6 of aceclofenac nanoparticle was found -26.6mV Figure 10. The morphology of the

nanoparticles by solvent evaporation method was investigated by Scanning electron

microscopy (SEM). It was observed that the nanoparticles were uniformly spherical in shape

Figure 11.

Figure 9 Particle size data of optimized nanoparticle formulation F6

Figure 10 Zeta potential data of nanoparticle formulation F6

Figure 11 SEM image of optimized nanoparticle formulation F6Stability studies results indicated no significant changes in the parameter even when it was

subjected to testing for 2 months when F6 was studied for short term storage conditions, the

drug content in the formulation within the 95% confidence interval and hence slight decrease

in the drug content was statistically not significant. From the stability studies it was

confirmed that nanoparticle formulations of aceclofenac remained more stable at storage

conditions Table 5.

Table 5 Stability study of optimized formulation (F6) of aceclofenac nanoparticles

formulation

Storage Temperatur

e 25°C ±20C /65%RH 40°C ±20C /70%RH

Parameter

% Drug

content

% Entrapment efficiency

Cumulative % drug Release

% Drug content

% Entrapment efficiency

Cumulative % drug Release

Initial97.20±1.46

91.88±1.38

98.07±0.73

97.20±1.46

91.88±1.38

98.07±0.73

30 Days96.92±1.23

91.73±1.45

97.54±1.16

96.48±1.22

90.91±1.44

96.66±1.15

60 Days96.85±1.16

91.26±1.75

97.15±1.23

96.41±1.15

90.44±1.73

96.27±1.22

Conclusion

Aceclofenac loaded nanoparticles were prepared by solvent evaporation technique. The

obtained nanoparticles were characterized by Scanning electron microscopy. The images

clearly reveal that the particles were in nano range. The drug content was found to be

97.20±1.46 %. The entrapment efficiency of nanoparticles was observed as 91.88±1.38.

Thus, this study concluded that the aceclofenac nanoparticles are suitable candidates that

provide the best anti-inflammatory and analgesic activities prolong action of the drug

nanoparticles.

References

1. S Daisy Chella Kumari, CB Tharani, N Narayanan, C Senthil Kumar (2013) Formulation

and characterization of Methotrexate loaded sodium alginate chitosan Nanoparticles.

Indian Journal of Research in Pharmacy and Biotechnology 1(6): 915-921.

2. Sundar Lal Tripathi, Kapil Rana, Vaibhav Rathore, Abhinav Kumar (2013) Development

and Optimization of Ranitidine Hydrochloride Nanospheres by 3 2 Factorial Design.

International Journal of Pharma Professionals Research 4(4): 928-932.

3. Sanjay J Kshirsagar (2013) Nanoparticle for colon specific drug delivery system. Journal

of Nanomedicine & Nanotechnology 4(6).

4. Sarita Kumari Yadav, Shivani Mishra, Brahmeshwar Mishra (2012) Eudragit-Based

Nanosuspension of Poorly Water-Soluble Drug: Formulation and In Vitro–In Vivo

Evaluation. AAPS Pharm Sci Technology 13(4): 1031-1044.

5. Sharma R, Yasir M, Bhaskar S. Formulation and evaluation of paclitaxel loaded PSA-

PEG nanoparticles. J Appl Pharm Sci 2011; 01:96-98.

6. Hecqa J, Deleers M, Fanara D, Vranckx H, Amighi K. Preparation and Characterization

of nanocrystals for solubility and dissolution rate enhancement of nifedipine. Int J Pharm

2005; 299:167-77.

7. Savjani KT, Gajjar AK, Savjani JK. Drug solubility: importance and enhancement

techniques. ISRN Pharm 2012; 2012:195727.

8. Nair R, Arunkumar KS, Priya KV, Sevukarajan M. Recent advances in solid lipid

nanoparticle based drug delivery systems. J Biomed Sci Res 2011; 3:368-84.

9. Mohante S, Boga PK. Role of nanoparticles in drug delivery system. Int J Res Pharm

Biomed Sci 2010;1:41-66.

10. Soppimath KS, Aminabhavi TM, Kulkarni, AR, Rudzinski WE. Biodegradable Polymeric

nanoparticles as drug delivery devices. J Control Release 2001:1-20.

11. Grau M, Montero JL, Guasch J, Felipe A, Carrasco E, Julia S. 1991. The pharmacological

profile of aceclofenac, a new non steroidal anti-inflammatory and analgesic drug. Agents

Actions Suppl. 32, 125-129.

12. Hinz B, Auge D, Rau T, Rietbrock S, Brune K, Werner U. 2003. Simultaneous

determination of aceclofenac and three of its metabolites in human plasma by high

performance liquid chromatography. Biomed.Chromatogr.17,268-275.

13. Dooley M, Spencer CM, Dunn CJ. 2001. Aceclofenac: a reappraisal of its use in the

management of pain and rheumatic disease. Drugs. 61, 1351-78.

14. Kalpana M, Sistla R, Shastri NR. 2015. Modulating drug release profiles by lipid semi

solidmatrix formulations for BCS class II drug- an in vitro and in vivo stud. Drug Deliv.

22(3), 418-26.

15. Eliska Vaculikova, Veronika Grunwaldova, Vladimir Kral, Jiri Dohnal, Josef Jampilek.

Preparation of Candesartan and Atorvastatin Nanoparticles by Solvent Evaporation.

Molecules 2012, 17, 13221-13234.

16. Shendge RS, Sayyad FJ. Formulation development and evaluation of colonic drug

delivery system of Budesonide microspheres by using spray drying technique. J Pharm

Res 2013;6:456-61.

17. Bathool A, Vishakante GD, Khan MS, Shivakumar HG. Development and

characterization of atorvastatin calcium loaded chitosan nanoparticles for sustain drug

delivery. Adv Mater Lett 2012;3:466-70.

18. Nesalin JA, Smith AA. Preparation and evaluation of chitosan nanoparticles containing

zidovudine. Asian J Pharm Sci 2012;7:80-4.

19. Singh A, Nainwal P, Nanda D, Jain DA. Solubility enhancement study of pioglitazone

using solid dispersion as solubilization technique. IJSID 2011;1:95-100.

20. Dattatraya Manohar Shinkar, Avinash Sridhar Dhake and Chitral Mallikarjuna Setty.

Drug Delivery from the Oral Cavity: A Focus on Mucoadhesive Buccal Drug Delivery

Systems. PDA J Pharm Sci and Tech 2012, 66 466-500.

21. Deelip Derle , Omkarjoshi, Ashish Pawar,Jatin Patel, Amol Jagadale. Formulation and

evaluation of buccoadhesive bi-layer tablet of propranolol hydrochloride. International

Journal of Pharmacy and Pharmaceutical Sciences, Vol. 1, Issue 1, July-Sep. 2009

22. Brahmankar D M and Jaiswal S B. Biopharmaceutis and Pharmacokinetics: A Tretise,

Vallabh Prakashan, New Delhi, 1st edition, 2006, 335-357.

23. PauloCosta, José ManuelSousa LoboModeling and comparison of dissolution profiles.

European Journal of Pharmaceutical Sciences. Volume 13, Issue 2, May 2001, Pages 123-

133

24. KORSEMEYER, R.W.; GURNY, R.; DOELKER, E. M.; BURI, P.; PEPPAS, N. A.

Mechanism of solute release from porous hydrophilic polymers. Int. J. Pharm., v.15,

p.25-35, 1983.