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Available online at ajdhs.com 

Asian Journal of Dental and Health Sciences 
Open Access to Pharmaceutical and Medical Research 

Copyright  © 2022 The  Author(s): This is an open-access article distributed under the terms of the CC BY-NC 4.0 
which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use provided the 

original author and source are credited 
 

 

 

Formulation and Evaluation of Sustained Release Solid Dispersed 
Nifedipine Microcapsules 

Ayushi Patel, Rupesh Kumar Jain, Vivek Jain, Pushpendra Kumar Khangar* 

Adina Institute of Pharmaceutical Sciences, NH86A, Lahdara, Sagar, MP, 470001 

Article Info: 
_______________________________________ 
Article History: 
Received 03 Sep 2022      
Reviewed 24 Oct 2022 
Accepted 08 Nov 2022 
Published 23 Nov 2022 

_______________________________________ 
Cite this article as:  

Patel A, Jain RK, Jain V, Khangar PK, 
Formulation and Evaluation of Sustained 
Release Solid Dispersed Nifedipine 
Microcapsules, Asian Journal of Dental and 
Health Sciences. 2022; 2(3):12-18 

DOI: http://dx.doi.org/10.22270/ajdhs.v2i3.21                                      

_______________________________________

*Address for Correspondence:   

Pushpendra Kumar Khangar, Adina Institute of 
Pharmaceutical Sciences, NH86A, Lahdara, 
Sagar, MP, 470001 

Abstract 
___________________________________________________________________________________________________________________ 

Conventional drug delivery system for treating the angina and hypertension are not much effective as 

the drug do not reach the site of action in appropriate amounts. Thus potent and guarded therapy of this 

angina and hypertension disorder using specific drug delivery system is a challenging task to the 

pharmaceutical professionals. The study was aimed at increase the solubility of poorly soluble drug 

nifedipine and formulating it in sustained release dosage form. Solid dispersion of drug was prepared 

using Poly vinyl pyrrolidone (PVP) as inert hydrophilic carriers by solvent evaporation technique. A 

17-fold increase in dissolution rate of nifedipine was observed with solid dispersion prepared with PVP 

(K30). Sustained release microcapsules of nifedipine were formulated using Eudragit RS 100 as a 

polymer, acetone as polymer solvent for Eudragit RS100, N-hexane as a non-solvent, liquid paraffin 

vehicle, with solid dispersion of nifedipine as core by emulsion solvent evaporation method and 

modified emulsion solvent evaporation method. Microcapsules from all the batches were found to 

discrete, spherical and free flowing and % entrapment efficiency was found to be in range of 96.01% to 

97.87%. All the batches of microcapsules showed sustained release curve in pH 7.4 phosphate buffer up 

to 12hours with maximum release up to 97.22% after 12hrs was found to be in B2. SEM studies of the 

microcapsules showed the surface topography states that prepared microspheres were spherical in 

shape. Shiny and uniform covered surface with polymer. 

Keywords: Nifedipine, Poly vinyl pyrrolidone, Solid dispersion, Microcapsules, Emulsion solvent 
evaporation method 

 

Introduction 

Hypertension is one of the most common cardiovascular 
diseases, which have become the leading cause of death for 
human1, 2. Successful treatment of hypertension in clinical 
practice means maintenance of blood pressure at a normal 
physiological level. In long-term therapy for the treatment of 
hypertension, the antihypertensive drugs have to be taken for 
life. In general, conventional formulations of the 
antihypertensive drugs need to be administered twice or three 
times a day to achieve effective therapeutic concentration, 
which results in marked blood pressure fluctuations and poor 
patient compliance. However, the formulations of drug 
sustained (controlled) release delivery systems have many 
advantages including reduced frequency of administration and 
fluctuation in plasma drug concentration, maintained stable 
blood pressure and improved patient compliance3,4. Therefore, 
the oral drug sustained (controlled) release delivery systems 
for the treatment of hypertension are an ideal solution. 
Nifedipine is a calcium channel blocker of the dihydropyridine 
type which is mainly used for the treatment of hypertension 
and angina pectoris. Nifedipine is a suitable candidate for CR 
administration due to its short elimination half-life of 2-4 hrs, 
its rapid and complete drug absorption over the entire 
gastrointestinal tract, despite its low water solubility and the 
relationship between drug plasma concentrations and blood 
pressure reduction. The importance of reduced peak plasma 

levels in order to avoid adverse effects such as reflex 
tachycardia has also been demonstrated5. Numerous attempts 
have been made to modify the dissolution characteristic of 
drug to attain more rapid and complete absorption6-8. Solid 
dispersion is one of the techniques which are originally used 
to enhance the dissolution rate of poorly water-soluble drugs 
using inert hydrophilic carriers9. The enhancement in the 
dissolution rate is obtained by one or a combination of the 
following mechanism: eutectic formation, increased surface 
area of the drug due to precipitation in the carrier, formation 
of true solid solution, improved wettability due to close 
contact with a hydrophilic carrier, precipitation as a 
metastable crystalline form or a decrease in substance 
crystallinity. The type of solid dispersion formed depends on 
both the carrier-drug combination and the method of 
manufacture10. Hydrophilic polymers like polyethylene glycols 
(PEG) 11-13. Polyvinyl pyrrolidone (PVP) 14,15 and hydroxyl 
propyl methyl cellulose (HPMC) 16 are among the popular 
carriers commonly used to prepare solid dispersions. Being 
freely soluble in water, these polymers are mainly used as 
excipients, to enhance the dissolution rate of drugs17, 18. 
Pluronic F-68 is being used as a newer material for 
preparation of solid dispersion to enhance the dissolution rate 
of poorly water soluble nifedipine19. The aim of this study is to 
improve the solubility of the poorly water soluble drug 
nifedipine by preparing solid dispersions using various 
hydrophilic carriers and using optimized solid dispersion to 

                       Open Access                                                                                                                                                                                                       Research Article                                                                           

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fabricate microcapsules for sustained release delivery of the 
drug with better bioavailability. 

Materials and methods  

Materials  

Nifedipine was obtained from Cipla Ltd. Mumbai, India. 
Polyvinyl pyrrolidone K30 was obtained as a gift from 
Blessings Pharmaceuticals Nagpur, India. Eudragit RS 100 was 
obtained as a gift from Rohm Pharma GMBH, Germany. Liquid 
paraffin was obtained from Shaw Wallace, India. Methanol, 
acetone was purchased from Loba Chemicals, India. Other 
reagents/chemicals were of AR/GR grade and purchased 
locally.  

Method 

Preformulation study20-22  

Solubility 

Solubility study was conducted to determine the effect of 
different buffers on the drug. An excess amount of drug was 
dispersed in 5 ml of distilled water, methanol, acetone, 
phosphate buffer solution (pH 6.8 and 7.4), 0.1N HCl, in glass 
stoppered tubes respectively, all the glass tubes were closed 
with stopper and covered with cellophane membrane to avoid 
solvent loss. Tubes were kept in water bath shaker at 37°C for 
24 hrs. As the samples attain equilibrium, they were subjected 
for centrifugation at 3000 RPM for about 5 minutes. After 
completion of centrifugation the samples get separated, then 
supernatant liquid is filtered through membrane filter and 
then analyzed by UV spectrophotometer at 238nm 
respectively. 

Melting point determination 

Melting point of nifedipine was determined by open capillary 
method.  

Determination of partition coefficient 

25 mg of nifedipine with aqueous phase and n-octanol was 
taken in three separating funnels. The separating funnels were 
shaken for 2 hrs in a wrist action shaker for equilibration. Two 
phases were separated and the amount of the drug in aqueous 
phase was analyzed spectrophotometrically. The partition 
coefficient of the drug in phases was calculated. 

Determination of λmax 

A solution of nifedipine containing the concentration 10µg/ml 
was prepared in phosphate buffer 7.4 pH and UV spectrum 
was taken using Shimadzu (UV-1800) double beam 
spectrophotometer. The solution was scanned in the range of 
200- 400 nm. 

Preparation of standard calibration curve of nifedipine 

100mg of drug was accurately weighed and dissolved in 
100ml phosphate buffer 7.4 pH in 100 ml volumetric flask, to 
make (1000μg/ml) standard stock solution (1). Then 10 ml 
stock solution (1) was taken in another 100 ml volumetric 
flask to make (100μg/ml) standard stock solution (2), then 
again 0.5, 1, 1.5, 2, 2.5 and 3.0 ml of stock solution (2) was 
taken in another 10 ml volumetric flask and then final 
concentrations were prepared 5, 10, 15, 20, 25 and 30μg/ml 
with distilled water. The absorbance of standard solution was 
determined using UV/VIS spectrophotometer (Shimadzu UV-
1800) at 238nm. Linearity of standard curve was assessed 
from the square of correlation coefficient (r2) which 
determined by least-square linear regression analysis. 

FTIR spectroscopy 

The concentration of the sample in KBr should be in the range 
of 0.2% to 1 %. The pellet is a lot thicker than a liquid film, 
consequently a decrease concentration in the sample is 
required (Beer's Law). For the die set that you'll be the usage 
of, about 80 mg of the mixture is wanted. Too excessive of an 
attention causes typically difficulties to obtain clean pellets. 
FTIR spectra of the samples were recorded over a spectral 
region from 4700 to 400 cm-1 using 20 scans with 4 cm-1 
resolution. 

Preparation of solid dispersions  

All procedures of experiments were performed in darken 
conditions for avoidance nifedipine light deprivation 

Physical mixtures procedure 

Nifedipine and polymer PVP-K30 taken in various 
concentrations like (1:2, 1:4, 1:6, and 1:8) 23. 

Solid dispersions procedure 

Using solvent evaporation technique, nifedipine as well as PVP 
K-30 uniformly dissolved in methanol taking various 
concentrations like (1:2, 1:4, 1:6, 1:8 and 1:10) after wards at 
400C the solvent evaporated. Resultant solid dispersed 
material passed through 100 meshes sieve. 

Solid dispersion evaluation  

Estimation solubility procedure 

The solubility study carried out for pure nifedipine, prepared 
physical mixtures and solid dispersions using thermostatic 
shaker water bath. Concentrated saturated solutions in 0.1 N 
HCl shake for 96 hrs at 370C. At end solutions were removed 
filtered diluted drug concentration was found by 
spectrophotometrically at 238 nm23, 24.  

Estimation of nifedipine  

Precisely weighted nifedipine samples were hauling out into 
methanol then extracts diluted using buffer solution (pH–7.4). 
Resultant extract analysed for nifedipine 
spectrophotometrically at 238 nm against buffer solution (pH 
7.4) used blank solution. The method followed beers lamberts 
law in concentration range of 1-10μg/ml23, 24.   

Solid dispersions in vitro dissolution 

Studies performed using (type II) USP XXIV dissolution test 
apparatus using the media 0.1 N HCl 900ml Dissolution 
medium for 1 hr, at 50 rpm and 370C- 10C temperatures. 5ml 
of samples taken at different time intervals and 5ml of same 
dissolution medium added to maintain sink condition. 
Withdrawn aliquots suitably diluted and analysed at 238 nm 
using U.V. Spectrophotometer. The percent release of 
nifedipine calculated and graph plotted against time23, 24. 

Formulation of microcapsules  

Two techniques used to prepare microcapsules. Emulsion 
solvent evaporation (ESE) and modified emulsion solvent 
evaporation (MESE). In each case of this techniques, Eudragit 
RS 100 as a polymer, acetone as polymer solvent for Eudragit 
RS100, N-hexane as a non- solvent, liquid paraffin vehicle, in 
following A1, A2 and B1, B2 batches using 1:2 and 1:4 Core to 
coat ratios for each25.  

Emulsion solvent evaporation method (ESE) 

Polymer dissolved in 15ml acetone. Solid dispersed nifedipine 
added into polymeric solution with agitation. Then obtained 
mixture transpired drop wise by syringe having needle size 
(15guage,2.5 inch) to the dispersion media containing liquid 
paraffin 100ml, containing Polysorbate ( Tween 80) (1%) w/w 
contained beaker study stirring at 600 rpm. at 250C- 200C 



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(room temperature) until solvent acetone completely 
evaporated. Lastly liquid paraffin separated by decantation 
and filtration procedure. Collected microcapsules washed 
using N-hexane for removal of traces of vehicle. The prepared 
microcapsules then dried at room temperature25, 26. 

Modified emulsion solvent evaporation method (MESE)  

This technique was same as ESE method. Difference is that 
when addition of polymeric solution in over after 10-15min n-
hexane was poured to vehicle phase. Acetone to hexane ratio 
3:2. Produced microcapsules processed like a process given 
for ESE method25,26. 

Evaluation of microcapsules27-30  

Drug content determination 

From precisely weighted sample nifedipine haul out inside 
methanol, and then aliquots marked up using buffer solution 
(pH-7.4). Resultant extract analysed for nifedipine 
spectrophotometrically at 238nm against buffer solution (pH 
7.4) used blank solution. Technique pursued beers lamberts 
law within 1-10μg/ml concentration range.  

Encapsulation efficiency 

Sieved microcapsules (50 mg) were grounded in a mortar and 
the drug content was extracted in pH 7.4 phosphates buffer. 
After suitable dilution of the sample, the drug content was 
analyzed spectrophotometrically at a wavelength of 238nm. 
Every batch of microcapsule was analyzed in a triplicate.  

Particle size 

Particle size determined using Sieve shaker, using different 
range of standard sieve and the quantity failed on different 
sieves were noted measured and standard (Avg) diameter of 
the particle was calculated. 

Invitro dissolution 

The dissolution studies performed using (type II) USP XXIV 
dissolution rate test apparatus in 0.1 N HCl for 2 hrs followed 
by pH 7.4 900ml dissolution medium containing 20% 
methanol at 50 rpm and 370C, temperature up to 12 hrs. 5ml 
of samples taken at different time intervals and 5ml of same 
dissolution medium added to maintain sink condition. 
Withdrawn aliquots diluted and analysed 
spectrophotometrically on 238 nm using U.V. 
Spectrophotometer. Nifedipine percent release calculated and 
graph plotted against time. 

Accelerated stability study  

The microcapsules from the selected and optimized batch 
were studied for stability and kept under the accelerated 
conditions of temperature and moisture (humidity) for the 
period of six months. These microspheres stability was 
studied at temperature 40°C and Humidity 75% RH 
conditions. Every sample separately weighed and enclosed by 
aluminium foils and sealed in black PVC bottle and kept in 
specified conditions at humidity chamber for six months. The 
formulations were checked for physical changes also analysed 
for dissolution study.  

Scanning electron microscopy (SEM) study  

Microcapsules mounted directly on scotch double adhesive 
tape analysed under scanning electron microscope SEM 
model, S-410 operated at 15K SEM thickness of 100% using 
Hitachi vacuum at 15 kv.  

Results and Discussion 

The nifedipine is found to be soluble in methanol, chloroform, 
freely soluble in phosphate buffer (pH 7.4) and practically 
insoluble in ethanol and distilled water. The melting point of 
nifedipine was 170 ºC -174ºC and λ max of nifedipine was found 
to be 238nm by using U.V. spectrophotometer (Shimadzu UV-
1800). The calibration curve of nifedipine was found to be 
linear in the concentration range of 5-30µg/ml at 238nm 
Figure 1. The partition coefficient of nifedipine was found to 
0.562 in octanol: water. Identification of nifedipine was done 
by FTIR spectroscopy with respect to marker compound. It 
was identified from the result of IR spectrum as per 
specification Figure 2. As concerned with solubility of the solid 
dispersions, it was found that drug, polymer ratios (1:8) 
shown enhanced solubility than other batches. Prepared 
whole batches of physical-mixture represented reduced 
solubility of drug and discharge than solid dispersions. Batch 
of solid dispersions composed 1:8 shown more discharge of 
drug. The pure nifedipine was shown 9.2% released within 
one hr. The enhanced drug dissolution is because of wetting 
ability enhanced also solubilization effect of polymer near 
diffusion level, another parameter is expansion of nifedipine 
solubilization through solid dispersion is due to the 
amorphous structure of nifedipine, no aggregation, particle 
size reduction in solid dispersions. Nifedipine solubility from 
dispersion was enhanced as extent of PVP K-30 increased up 
to 1:8, after increase in concentration of PVP decreased the 
dissolution. Reason might be that high polymer proportions 
cause’s difficulty in leaching to drug during dissolution Table 1 
& 2. The drug content of all physical mixture lies between 8.50 
to 32.49 % and for solid dispersions it was 8.20 to 31.69 % 
Table 3 & 4. Dissolution profile of physical mixture and solid 
dispersions was given in Table 5 & 6. The microencapsulating 
efficiency determined by using drug content of microcapsules 
and formula. Nifedipine amount for total batches perceived in 
uniform quantity. The higher percentage of 97.87% 
entrapment efficiency was found in batch B2 when compare to 
other formulation Table 7. An in vitro dissolution rate study 
was done for whole batches of microcapsules. Batch A1 shown 
78% drug release up to 12 hrs, Batch A2 (94.012%) and batch 
B1 shown 82.32 % drug release and batch B2 (98.22%) 
showed highest percentage of drug release up to 12 hrs. This 
study reveals as the polymer amount raised the drug release 
retarded. The drug released by erosion of coating material. In 
MESE methodology, hexane added which is miscible in 
acetone as well as liquid paraffin. Little bit amount of Hexane 
get miscible with liquid paraffin increases attraction of liquid 
paraffin to acetone leads in an enhanced extent of solvent 
evaporation Figure 3. The microcapsules from the selected 
and optimized batch (B2) were studied for stability and kept 
under the accelerated conditions like raised temperature and 
moisture up to period of six months. The results revealed no 
marked alterations in physical appearance and drug releasing 
properties Figure 4. The surface topography states that 
prepared microspheres were spherical in shape. Shiny and 
uniform covered surface with polymer Figure 5. 

 



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Figure 1: Wavelength maxima of nifedipine  

 

Figure 2: FT-IR spectrum of pure drug (nifedipine) 

Table 1: Solubility study of physical mixture 

Carrier Concentration of nifedipine in physical mixture (µg/ml) 

1:2 1:4 1:6 1:8 1:10 

PVP(K30) 7.483 7.882 9.905 9.563 8.963 

 

Table 2: Solubility study of solid dispersion 

Polymer Concentration of nifedipine in solid dispersion (µg/ml) 

1:2 1:4 1:6 1:8 1:10 

PVP (K30) 12.321 14.516 15.65 17.898 15.762 

Pure nifedipine: Solubility found to be 8.94 µg per ml 

Table 3: Nifedipine %yield physical mixture 

Sr. No. Nifedipine: povidone Theoretical yield mg 

% 

Physical mixture 

practical yield  

% 

1. 1:2 33.33 32.49 

2. 1:4 20 19.53 

3. 1:6 14.28 13.03 

4. 1:8 11.11 10.24 

5. 1:10 9.09 8.50 

 



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Table 4: Nifedipine %yield solid dispersions 

Sr. No. Nifedipine: povidone Theoretical Solid dispersions practical 

1. 1:2 33.33 31.69 

2. 1:4 20 19.23 

3. 1:6 14.28 12.56 

4. 1:8 11.11 10.04 

5. 1:10 9.09 8.20 

 

 

Table 5: Dissolution profile of physical mixture 

Time Min Nifedipine Povidone (1:2) Povidone (1:4) Povidone (1:6) Povidone (1:8) Povidone (1:10) 

0 0 0 0 0 0 0 

10 0.89 1.53 2.62 3.92 5.03 5.5 

20 1.92 3.89 5.01 6.03 7.12 8.12 

30 2.85 4.56 8.05 8.12 10.9 9.98 

40 5.06 8.21 11.12 12.52 15.56 15.78 

50 7.36 10.72 14.31 15.62 18.52 18.21 

60 9.29 13.91 17.17 19.06 22.06 22.56 

 

 

Table 6: Solid dispersions dissolution profiles 

Time Min Nifedipine Povidone (1:2) Povidone (1:4) Povidone (1:6) Povidone (1:8) Povidone (1:10) 

0 0 0 0 0 0 0 

10 0.65 7.53 9.52 13.87 15.72 12.56 

20 1.82 13.9 19.25 26.52 32.52 28.57 

30 2.2 19.8 28.82 35.21 48.25 43.56 

40 5.06 28.06 39.56 49.72 63.21 59.15 

50 7.3 35.72 49.25 61.82 78.92 72.76 

60 9.2 43.57 59.52 75.21 96.31 87.65 

 

 

Table 7: Drug content and entrapment efficiency 

Sample % Drug content % of Entrapped 

Pure drug 99.97 ------- 

A1 10.89 96.01 

A2 8.79 96.69 

B1 10.76 96.84 

B2 8.89 97.87 



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Figure 3: Cumulative % drug release of all batches 

 

Figure 4: Cumulative % Drug release study of optimized formulation at accelerated conditions 

 

Figure 5: Microcapsules batch B2 at 15kV 50x 

Conclusion  

Extended release dosage forms of nifedipine are difficult to 
formulate due to its poor solubility. Approach of solid 
dispersion was employed in which hydrophilic carriers like 
PVP were used. PVP markedly enhanced the dissolution rate of 
nifedipine. IR studies also indicated no chemical interaction 
between nifedipine and excipient. Thus, solid dispersion was 
then microencapsulated using different material using 
emulsion solvent evaporation method and modified emulsion 
solvent evaporation method. Microcapsules formulated were 
found to be spherical and discrete as seen in SEM 

photomicrographs and were also having good encapsulating 
efficiency. Nifedipine release up to 97.22% after 12hrs was 
observed.  

References 

1. Akinboboye O, Idris O, Akinkugbe O. Trends in coronary artery 
disease and associated risk factors in sub-Saharan Africans. J Hum 
Hypertens. 2003; 17(6):381-7. 
https://doi.org/10.1038/sj.jhh.1001562 

2. Okpechi IG, Rayner BL. Impact of recent landmark clinical trials on 
hypertension treatment. Clin Investig. 2011; 1(8):1141-54. 
https://doi.org/10.4155/cli.11.97 

https://doi.org/10.1038/sj.jhh.1001562
https://doi.org/10.4155/cli.11.97


Patel et al                                                                                                                                      Asian Journal of Dental and Health Sciences. 2022; 2(3):12-18 

[18]                                                                                                                                                                                                                                                 AJDHS.COM 

3. Barakat NS, Almurshedi AS. Design and development of gliclazide-
loaded chitosan microparticles for oral sustained drug delivery: 
in-vitro/in-vivo evaluation. J Pharm Pharmacol. 2011; 63(2):169-
78. https://doi.org/10.1111/j.2042-7158.2010.01214.x 

4. Sousa e Silva JP, Lobo JS, Bonifácio MJ, Machado R, Falcão A, Soares-
da-Silva P. In-vivo evaluation of prolonged release bilayer tablets 
of anti-Parkinson drugs in Göttingen minipigs. J Pharm Pharmacol. 
2011; 63(6):780-5. https://doi.org/10.1111/j.2042-
7158.2011.01278.x 

5. Derakhshandeh K, Soleymani M. Formulation and in vitro 
evaluation of nifedipine-controlled release tablet: Influence of 
combination of hydrophylic and hydrophobic matrix forms. Asian 
J Pharm. 2010; 4(4):185-193. https://doi.org/10.4103/0973-
8398.76739 

6. Lin SL, Menig J, Lachman L. Interdependence of physiological 
surfactant and drug particle size on the dissolution behavior of 
water-insoluble drugs. J Pharm Sci. 1968; 57(12):2143-8. 
https://doi.org/10.1002/jps.2600571225 

7. Kornblum SS, Hirschaorn JO. Dissolution of poorly water-soluble 
drugs. J Pharm Sci. 1970; 56:606-614. 
https://doi.org/10.1002/jps.2600590506 

8. Parrot EL. Milling of pharmaceutical solids. J Pharma Sci. 1974; 
63:813-820. https://doi.org/10.1002/jps.2600630603 

9. Chiou WL, Riegelman S. Pharmaceutical application of solid 
dispersion systems. J Pharma Sci.1971; 60:1281-1302. 
https://doi.org/10.1002/jps.2600600902 

10. Serajuddin ATM. Solid dispersion of poorly water-soluble drugs: 
early promises, subsequent problems and recent breakthroughs. J 
Pharm Sci. 1999; 88:1058-1066. 
https://doi.org/10.1021/js980403l 

11. Sheen P, Khetarpal VK, Cariola CM, Rowlings CE. Formulation 
studies of poorly water soluble drug in solid dispersion to 
improve bioavaibility. Int J Pharm. 1995; 118:221-227. 
https://doi.org/10.1016/0378-5173(94)00366-D 

12. Sahu V, Jadon AS, Jain N, Yadav R, Jain PK, Khare B, Jain A, Review 
on Microspheres as Drug Carriers for Controlled Drug Delivery. 
International Journal of Medical Sciences and Pharma Research, 
2021; 7(2):1-9 https://doi.org/10.22270/ijmspr.v7i2.53 

13. Mooter VG, Augustijns P, Blaton N, Kinget R. Physico-chemical 
characterization of solid dispersion of temazepam with 
polyethylene glycol 6000 and PVP K30. Int J Pharm. 1998; 164:67-
80. https://doi.org/10.1016/S0378-5173(97)00401-8 

14. Tantishaiyakul V, Kaewnopparat N, Ingkataworn WS. Properties of 
solid dispersion of piroxicam in polyvinylpyrrolidone K-30. Int J 
Pharm. 1996; 143:59-66. 11. https://doi.org/10.1016/S0378-
5173(96)04687-X 

15. Torrado S, Torrado JJ, Cadorniga R. Preparation dissolution and 
characterization of albendazole solid dispersion. Int J Pharm. 
1996; 140:247-250. https://doi.org/10.1016/0378-
5173(96)04586-3 

16. Ho H, Su H, Tsai T, Sheu M. The preparation and characterization of 
solid dispersion on pellets using a fluidized bed system. Int J 

Pharm. 19996; 139:223- 229. https://doi.org/10.1016/0378-
5173(96)04594-2 

17. Perng CY, Kearney AS, Patel K, Palepu NR, Zuber G, et al. 
Investigation of formulation approaches to improve the 
dissolution of SB-210661, a poorly water soluble 5-lipoxygenase 
inhibitor. Int J Pharm. 1998; 176:31-38. 
https://doi.org/10.1016/S0378-5173(98)00296-8 

18. Nair R, Gonen S, Hoag SW. Influence of polyethylene glycol and 
povidone and the polymorphic transformation and solubility of 
carbamazepine. Int J Pharm. 2002; 240:11-16. 
https://doi.org/10.1016/S0378-5173(02)00083-2 

19. Mehta KA, Kislalioghu MS, Phuapradit W, Malick W, Shah NH. Multi 
unit controlled release systems of nifedipine and nifedipine: 
Pluronic F68 solid dispersions: Characterization of release 
mechanism. Drug Dev Ind Pharm. 2002; 28:275-286. 
https://doi.org/10.1081/DDC-120002843 

20. Nagarajan K, Rao MG. Formulation and dissolution studies of solid 
dispersions of nifedipine. Indian Journal of Novel Drug Delivery 
2010; 2:96-98. 

21. More CG, Dabhade PS, Jain NP, Aher BO. Solubility and dissolution 
enhancement of gliclazide by solid dispersion technique. Int J 
Pharm Chem Anal. 2015; 2(2):51-8.. 

22. Vo CL, Park C, Lee BJ. Current trends and future perspectives of 
solid dispersions containing poorly water-soluble drugs. Eur J 
Pharm Biopharm. 2013; 85(3):799-813. 
https://doi.org/10.1016/j.ejpb.2013.09.007 

23. Chowdary KPR, Ramesh S. Microencapsulation of solid dispersed 
Nifedipine-PVP system. Indian Drugs. 1995; 32 (10):477- 483. 

24. Arias MJ, Gines JM, Moyano JR, Rabasco AM. Dissolution properties 
and in vivo behaviour of triamterene in solid dispersions with 
polyethylene glycols. Pharmaceutica Acta Helvetiae. 1996; 
71(4):229-35. https://doi.org/10.1016/S0031-6865(96)00017-9 

25. Nokhodchi A, Farid D. Microencapsulation of paracetamol: By 
various emulsion techniques using cellulose acetate phthalate. 
Pharm Tech North America. 2002; 26(6):54-60. 

26. Wu PC, Huang YB, Chang JS, Tsai MJ, Tsai YH. Design and 
evaluation of sustained release microspheres of potassium 
chloride prepared by Eudragit®. Eur J Pharm Sci. 2003; 19(2-
3):115-22. https://doi.org/10.1016/S0928-0987(03)00069-1 

27. Gautam SP, Rai JP, Billshaiya U, Jain N, Vikram P, Jain DK. 
Formulation and evaluation of mouth dissolving tablet of 
loperamide. Int J Pharm Sci Res. 2013; 4(5):1782. 

28. Patel AN, Rai JP, Jain DK, Banweer JI. Formulation, development 
and evaluation of cefaclor extended release matrix tablet. Int J 
Pharm Pharm Sci. 2012; 4(4):355-7. 

29. Pandey SP, Khan MA, Dhote V, Dhote K, Jain DK. Formulation 
development of sustained release matrix tablet containing 
metformin hydrochloride and study of various factors affecting 
dissolution rate. Sch Acad J Pharm. 2019; 8(3):57-73. 

30. Jain P, Nair S, Jain N, Jain DK, Jain S. Formulation and evaluation of 
solid dispersion of lomefloxacin hydrochloride. Int J Res Pharm Sci 
2012; 3(4):604-608. 

 

https://doi.org/10.1111/j.2042-7158.2010.01214.x
https://doi.org/10.1111/j.2042-7158.2011.01278.x
https://doi.org/10.1111/j.2042-7158.2011.01278.x
https://doi.org/10.4103/0973-8398.76739
https://doi.org/10.4103/0973-8398.76739
https://doi.org/10.1002/jps.2600571225
https://doi.org/10.1002/jps.2600590506
https://doi.org/10.1002/jps.2600630603
https://doi.org/10.1002/jps.2600600902
https://doi.org/10.1021/js980403l
https://doi.org/10.1016/0378-5173(94)00366-D
https://doi.org/10.22270/ijmspr.v7i2.53
https://doi.org/10.1016/S0378-5173(97)00401-8
https://doi.org/10.1016/S0378-5173(96)04687-X
https://doi.org/10.1016/S0378-5173(96)04687-X
https://doi.org/10.1016/0378-5173(96)04586-3
https://doi.org/10.1016/0378-5173(96)04586-3
https://doi.org/10.1016/0378-5173(96)04594-2
https://doi.org/10.1016/0378-5173(96)04594-2
https://doi.org/10.1016/S0378-5173(98)00296-8
https://doi.org/10.1016/S0378-5173(02)00083-2
https://doi.org/10.1081/DDC-120002843
https://doi.org/10.1016/j.ejpb.2013.09.007
https://doi.org/10.1016/S0031-6865(96)00017-9
https://doi.org/10.1016/S0928-0987(03)00069-1

