“FORMULATION AND IN VITRO EVALUATION OF SOLID DISPERSION OF AZATHIOPRINE”

SYNOPSIS FOR

M.PHARM DISSERTATION

SUBMITTED TO

RAJIVGANDHIUNIVERSITY OF HEALTH SCIENCES

KARNATAKA.

BY

ALEKHYA NUVVULA

DEPARTMENT OF PHARMACEUTICAL TECHNOLOGY

P.E.SCOLLEGE OF PHARMACY

BANGALORE

(2011-12)

RAJIVGANDHIUNIVERSITY OF HEALTH SCIENCES,

KARNATAKA, BANGALORE.

ANNEXURE-II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

1 /

Name of the candidate and address

/ PRESENT ADDRESS
ALEKHYA NUVVULA
1st M. PHARM (PHARMACEUTICAL TECHNOLOGY)
PESCOLLEGE OF PHARMACY
HANUMANTH NAGAR
BANGALORE-560 050

PERMANENT ADDRESS
ALEKHYA NUVVULA
D/O N.V.RAMA RAO
ASWANI CHILDREN HOSPITAL
D.NO:4-292(1), DIBBALA ROAD
S.N PURAM, ONGOLE – A.P
PRAKASAM DT, PIN: 523002
2 / Name of the institution /

P.E.S.COLLEGE OF PHARMACY

50 FEET ROAD,
HANUMANTH NAGAR,
BANGALORE-560050.
3 / Course of study and subject /

MASTER OF PHARMACY IN PHARMACEUTICAL TECHNOLOGY

4 / Date of the admission / 9th SEPTEMBER 2011
5 /

Title of the topic:

“FORMULATION AND IN VITRO EVALUATION OF SOLID DISPERSION OF AZATHIOPRINE”
6. / Brief resume of the intended work:
6.1 Need for the study:
  • Solid dispersion is one of the most promising approach for solubility enhancement. The term solid dispersion refers to a group of solid products consisting of at least two different components, generally a hydrophilic matrix and a hydrophobic drug. The matrix can be either crystalline or amorphous.
  • The enhancement of oral bioavailability of such poorly water soluble drugs remains one of the most challenging aspects of drug development. The development of solid dispersions as a practically viable method to enhance bioavailability of poorly water-soluble drugs overcame the limitations of previous approaches such as salt formation, solubilization by cosolvents, and particle size reduction.Studies revealed that drugs in solid dispersion need not necessarily exist in the micronized state. A fraction of the drug might molecularly disperse in the matrix, thereby forming a solid dispersion. when the solid dispersion is exposed to aqueous media, the carrier dissolves and the drug releases as fine colloidal particles. The resulting enhanced surface area produces higherdissolutionrate and bioavailability of poorly water-soluble drugs. In addition, in solid dispersions, a portion of drug dissolves immediately to saturate the gastrointestinal tract fluid, and excess drug precipitates as fine colloidal particles or oily globules of submicron size.
  • Immunosuppressants are the class of drugs that perform immunosuppression of the immune system. They may be either exogenous, as immunosuppressive drugs, or endogenous. Azathioprine is a purine analogue immunosuppressive drug. It is insoluble in water. The present work is aimed at the development and evaluation of solid dispersion of azathioprine to enhance its solubility and bioavailability.
  • The design of effective formulations for drugs has long been a major challenge, because drug efficacy can be severely limited by poor solubility. One of the most promising technologies is the solid dispersion drug delivery system, which is being applied to enhance the solubility and bioavailability of poorly water soluble drugs.

Review of the literature:
  1. Patil SR et al carried out formulation of solid dispersion of aceclofenac using lactose, mannitol and urea 9:1, 7:3 and 4:1 ratios of the drug to polymer (by weight). In vitrorelease profiles of all solid dispersions were comparatively evaluated and also studied against pure aceclofenac. Faster dissolution was exhibited by SD containing 9:1 ratio of drug: lactose. The increase in dissolution rate of the drug may be due to increase in wettability, hydrophilic nature of the carrier and also due to reduction in drug crystallinity. The prepared Solid Dispersions was subjected for percent practical yield, drug content and infrared (I.R) spectroscopic studies. Absence of significant drugcarrier interaction was confirmed by I.R data.1
  2. Torrado S et al carried out solid dispersion systems of sparingly water soluble drug albendazole by mixing with varying concentration of polyvinylpyrrolidone (PVP K12) by co-precipitation method in order to improve the solubility and dissolution rate of albendazole. They carried out physical characterization by x-ray diffraction. They found that the dissolution and solubility rate of albendazole were increased when mixed with polyvinylpyrrolidone. An increase in concentration of polymer in solid dispersion resulted in both parameters by co-precipitation method.2
  3. Milani PZ et al carried out studies on dissolution enhancement of Prednisolone, a poorly water-soluble drug by solid dispersion technique. Solid dispersion of prednisolone was prepared with PEG 6000 or different carbohydrates such as lactose and dextrin with various ratios of the drug to carrier i.e., 1:10, 1:20 and 1:40 by coevaporation method. The evaluation of the properties of the dispersions was performed using dissolution studies, Fourier-transform infrared spectroscopy and x-ray powder diffractometery. The results indicated that lactose is suitable carriers to enhance the in vitro dissolution rate of prednisolone. The data from the x-ray diffraction showed that the drug was still detectable in its solid state in all solid dispersions except solid dispersions prepared by dextrin as carrier. The results from infrared spectroscopy showed no well-defined drug–carrier interactions for coevaporates.. Solid dispersion of a poorly water-soluble drug, prednisolone may alleviate the problems of delayed and inconsistent rate of dissolution of the drug.3
  4. Zerrouk Net alconducted in vitro and in vivo evaluation of carbamazepine-PEG 6000 solid dispersions. Solubility study showed that a linear increase in carbamazepine solubility with increase in PEG 6000 concentration. The dissolution profile indicated that percentage drug dissolved was dependent on proportion of PEG 6000. statistical analysis of pharmacokinetic parameter showed that the carbamazepine:PEG6000 binary systems displayed higher bioavailability of drug than pure drug.4
  5. Shah JC et alcarried out preformulation study of etoposide: II. Increased solubility and dissolution rate by solid-solid dispersions. They prepared solid-solid dispersions by coprecipitating the drug with polyethylene glycols (PEG) of different molecular weights in various ratios. It was found that the coprecipitate of etoposide with PEG 8000 (1:10, PEG weight fraction of 0.91) increased its solubility 2-fold and dissolution rate 42-fold. The co precipitates with other PEG’s (PEG 1500, PEG 3400, PEG 6000) and PVP 40000 also increased etoposide dissolution rate to a great extent.5
  6. Khoo SMetalformulated solubilising and non-solubilising solid dispersions containing amorphous Halofanterine free base using a simple fusion method requiring temperatures as low as 70°C. These formulations were evaluated in vivo in fasted beagles and in comparison to the commercial tablet, these afforded a five- to seven-fold improvement in absolute oral bioavailability. This study also showed that when Halofanterine was delivered in the amorphous form, the solubilising formulations did not offer significant bioavailability advantages over the non-solubilising formulation. A stability study of the non-solubilising Halofanterine:PEG 6000 formulation showed that it was stable at temperatures below 40°C and that a drug loading of 10% or less improved the stability of the formulation over longer periods. The physical stability of the solid dispersions was studied using differential scanning calorimetry and X-ray powder diffraction.6
  7. Urbanetz NA and LippoldBC carried out solid dispersions of nimodipine and polyethylene glycol 2000: dissolution properties and physico-chemical characterization. They prepared Solid dispersion of nimodipine in water using peg 2000 by melt embedding method.they investigated cooling rate during preparation and storage conditions like temperature and relative humidity. The formulation showed high dissolution rate due to absence of crystalline form of drug. They investigated physico chemical properties by using thermal analysis, x ray diffraction, macroscopic method. They concluded that determination of crystallinity and dispersivity of drug in solid dispersion can be successful by combining different methods like differential scanning colorimetry, hot stage microscopy, x ray diffraction.7
  8. Jachowicz R et al carried out solid dispersions of different ratios of Gelita collagel as the carrier and lactose were prepared by the spray drying method. The properties of the solid dispersions were characterized by X-ray diffraction and polarizing microscopic studies. An amorphous form of all prepared solid dispersions were indicated in X-ray studies. X-ray diffractions studies have shown an amorphous form of the drug to be present in all forms of solid dispersion, independent of the percentage of the carrier in the solid dispersion. The results of the studies showed that the dissolution rate of oxazepam increased markedly when present in solid dispersions in comparing to the physical mixtures and the pure drug. To overcome this problem lactose was added in various ratios during the formulation of the solid dispersion. The results of investigations showed the suitability of Gelita collagel as the carrier for solid dispersions of oxazepam. The amorphous form of oxazepam found in powdered solid dispersions as demonstrated by X-ray diffraction may offer an explanation of better dissolution rate from solid dispersion tablets. No crystallinity of oxazepam in Gelita Collagel solid dispersion has been found after one year of storage. The proposed tablet formulations with solid dispersion ensure a good pharmaceutical availability of oxazepam.8
  9. Hariprasanna RCet al carried out a study on formulation and processing factor influencing the release of felodipine. They formulated fast dissolving tablet by using croscarmellose sodium as super disintegrant and solid dispersion with polyvinyl alcohol (PVA) as a carrier. The tablets were characterized by FTIR study. They carried out pre compression parameter like angle of repose, % compressibility as well as post compression studies such as hardness, friability, in vitro disintegration time, wetting time and in vitro release studies, stability studies. They found that tablets prepared by solid dispersion having drug to carrier ratio of 1:4 (A3) yielded the best drug release in terms of dissolution rate. The results revealed that it is possible to enhance the dissolution rate of Felodipine by increasing the surface area of the drug by solid dispersion method. Tablets prepared by PVA solid dispersion of ratio 1:9 (A4) yielded best results in terms of dissolution rate. The formulation did not show any change in disintegration time, wetting time and drug content after stability period.9
  10. Kim EJ et alcarried out preparation of a solid dispersion of felodipine using a solvent wetting method using various carriers like pvp HPMC poloxamer. The results of DSC and XRD studies showed that felodipine in solid dispersions exists in the amorphous state in PVP, HPMC, and poloxamer, but not when sorbitol or mannitol is used as carriers. The dissolution rate of felodipine from PVP, HPMC, and poloxamer solid dispersions was markedly higher than from their corresponding physical mixtures. These results confirm that the solvent wetting method could be used to prepare felodipine solid dispersions using PVP, HPMC, and poloxamer as carriers, as a means of enhancing felodipine dissolution rates.10
  11. Badry ME et al carried out solid dispersions of indomethacin by using polymers like Gelucire 50/13 and PEG4000 by hot melt method at 1:1, 1:2, 1:4 drug to polymer ratio. Physical states of drug were examined by using differential scanning colorimetry, x-ray powder diffractrometry and scanning electron microscopy. The highest ratio of polymer (1:4) enhanced drug solubility about 4 folds and 3.5 folds in case of PEG and gelucire respectively. An increase in dissolution rate was observed at ph 1.2 and 7.4. They observed that formation of indomethacin –PEG solid dispersion destroyed almost completely the crystallinity of drug and represents a suitable modification for improving its bioavailability.11
  12. Kedzierewicz F et al carried out a 3 year stability study of tolbutamide solid dispersions and 13-cyclodextrin complex. They prepared solid dispersion by Solvent method and co-precipitate method. They compared the effect of aging on tolbutamide solid dispersions with PEG 6000 and tolbutamide-/3-cyclodextrin inclusion complex stored at three temperatures for 3 years by comparing the physicochemical characteristics followed by X-ray diffractometry, infrared spectrophotometry and differential thermal analysis. In all cases, during the 3 years of storage, no differences in IR spectra were found with respect to the fresh solid dispersions or complex. They also carried out dissolution profiles. Storage at room temperature and 5°C did not have any marked effect on the dissolution profiles for the tolbutamide-PEG 6000 coprecipitate. In conclusion, this study has demonstrated that it is possible to prepare stable solid dispersions for a long period of time. For both the comelt and the coprecipitate, only slight modifications can be observed in the physicochemical characteristics of the systems as well as for the dissolution properties.. It is therefore concluded that the three systems studied are potential candidates for further incorporation into dosage forms such as hard capsules or tablets.12
  13. Yan YD et al carried out novel valsartan-loaded solid dispersion with enhanced bioavailability and no crystalline changes with water, hydroxypropyl methylcellulose (HPMC) and sodium lauryl sulphate (SLS). The physicochemical properties of solid dispersions were characterized using scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The bioavailability of the solid dispersions in rats was evaluated compared to valsartan powder and a commercial product (Diovan®). It was observed that there were no changes in the crystalline form of drug which in turn could help overcome the physical instabilities of phase separation and recrystallization of amorphous phase associated with conventional solid dispersions. It gave a higher AUC, Cmax and shorter Tmax compared to valsartan powder and the commercial product. The solid dispersion improved the bioavailability of the drug in rats by about 2.2 and 1.7-fold in comparison with valsartan powder and the commercial product, respectively. Thus, the valsartan-loaded solid dispersion could be useful for delivering poorly water-soluble valsartan with enhanced bioavailability and without crystalline changes.13
  14. Kim JS et al carried out physicochemical properties and oral bioavailability of amorphous atorvastatin hemi-calcium using spray-drying and SAS process. Atorvastatin hemi-calcium trihydratewas transformed to anhydrous amorphous form by spray-drying and SAS process. They evaluated its phisico-chemical property and bioavailability. It showed better apparent solubility, dissolution and pharmacokinetic parameters compared to crystalline form of atorvastatin. AUC’s of all amorphous atorvastatin significantly increased compared to crystalline form. SAS process exhibited better bioavailability than spray drying because of particle size reduction. They concluded that SAS process was powerful methodology for improving phisico-chemical properties and bioavailability of atorvastatin.14
  15. Patel M et al carried out solubility enhancement of Lovastatin by using modified locust bean gum(LBG) as carrier Using Solid Dispersion Techniques. They modified the LBG by heating which increased viscosity irreversibly. They studied the effect of polymer concentration methods of preparation on solubility enhancement. They observed increase in solubility of Lovastatin with increase in concentration of MLBG(modified LBG). It was observed that dissolution rate of Lovastatin from its Solid Dispersion was dependent on method of preparation of solid dispersion. Dissolution study revealed that modified solvent evaporation is most convenient and effective method for solubility enhancement of Lovastatin among other methods. Characterizations of prepared solid dispersions were done by differential scanning colorimetry, scanning electron microscopy, x ray powder diffraction. They also conducted in vivo study in which they measured HMG co-A reductase activity. They observed significant reduction in HMG co-A reductase activity in case of solid dispersion LS than pure drug. Hence they concluded that MLGB could be used as potential carrier in enhancing the dissolution rate and bioavailability of Lovastatin.15
  16. Shavi GV et al prepared solid dispersion of gliclazide using PEG 4000, PEG 6000 using fusion method and using PVP K 30 by solvent evaporation method. It was observed that dissolution rate were enhanced compared to pure drug. The study clearly showed addition of PVP K 30 improved dissolution rate significantly due to solubilization and improved wetting of drug in PVP K 30. They concluded that solid dispersion of gliclazide using hydrophilic polymer would improve the solubility and dissolution rate.16
6.3 Main objectives of the study:
The objectives of the present study are as follows:
  1. To carry out the phase solubility studies of azathioprine with different carriers.
  2. To prepare solid dispersions ofazathioprine with different carriers.
  3. To characterize the prepared solid dispersions.
  4. To performin vitro dissolution studies of solid dispersions of azathioprine.
  5. To carry out the stability studies of the selected formulations.

Materials and methods:
7.1 Source of data:
  • The data will be obtained from the literature survey and internet source.
  • The data will be obtained from the experimental work, which includes formulation of solid dispersion by using different polymers, evaluation of drug content and stability studies.
7.2 Method of collection of data (including sampling procedures if any):
  • The data will be collected from prepared formulations subjected to different evaluation techniques, estimation of drug content, in-vitro drug release and stability studies.
7.3 Does the study require any investigation or interventions to be
Conducted on patients or other humans or animals?
- NO –
7.4 Has ethical clearance been obtained from your institution in case of
7.3?
- Not applicable -

/ LIST OF REFERENCES:
  1. PatilSR,Ravikumar, PatilMB, Paschapur MS, Rao VSNM. Enhancement of Dissolution Rate of Aceclofenac by solid Dispersion Technique. Int J PharmTech res. 2009;1(4):1198-204.
  1. TorradoS, TorradoS, JoseTorrado J, CaddrnigaR. Preparation, dissolution and characterization of albendazolesolid dispersions. Int J Pharm. 1996;140:247-50.
  1. Milani PZ, Nezhadi SH,Jalali MB, Mohammadi L, Nokhodchi A, Valizadeh H. Studies on Dissolution Enhancement of Prednisolone, a Poorly Water-Soluble Drug by Solid Dispersion Technique. Adv Pharm Bull. 2011;(1):48-53.
  1. ZerroukN, ChemtobC, ArnaudP, ToscaniS, DugueJ.In vitro and in vivo evaluation of carbamazepine-PEG 6000solid dispersions. Int J Pharm. 2001;225:49–62.
  1. Shah JC, Chen JR, ChowD. Preformulation study of etoposide: II. Increased solubilityand dissolution rate by solid-solid dispersions. Int J Pharm. 1995;113:103-11.
  1. Khoo SM, PorterCJH, CharmanWN. The formulation of Halofantrine as either non-solubilisingPEG 6000 or solubilising lipid based solid dispersions:Physical stability and absolute bioavailability assessment. Int J Pharm. 2000;205:65–78.
  1. UrbanetzNA, LippoldBC. Solid dispersions of nimodipine and polyethylene glycol 2000: dissolutionproperties and physico-chemical characterization Eur J Pharm Biopharm. 2005;59:107–18.
  1. Jachowicz R, NurnbergE. Enhanced release of oxazepam from tablets containing soliddispersions. Int J Pharm. 1997;159:149–58.
  1. Hariprasanna RC, Kulkarni U, Ahmad QJ, GururajSK, Srinath B.A study on formulation and processing factor influencing the release of felodipine. Int J Current Pharm Res. 2010;2(3).
  1. Kim EJ, Chun MK, Jang JS, Lee IH, LeeKR, Choi HK. Preparation of a solid dispersion of felodipine using a solventwetting method. Eur J Pharm Biopharm. 2006;64:200–5.
  1. Badry ME, Fetih G, Fathy M. Improvement of solubility and dissolution rate of indomethacin by solid dispersions in Gelucire 50/13 and PEG4000. Saudi Pharm J. 2009;17:217–25.
  1. Kedzierewicz F, Villieras F, Zinutti C, Hoffman M, Maincent P. A 3 year stability study of tolbutamide solid dispersions and13-cyclodextrin complex. Int J Pharm. 1995;117:247-51.
  1. Yana YD, Sunga JH, Kima KK, Kimb DW, Kima JO, Leec BJ et al.Novel valsartan-loaded solid dispersion with enhanced bioavailability and no crystalline changes. Int J Pharm. 2011;3(3):1-9.
  1. Kim JS, Kim MS, Park HJ,Jin SJ, Lee S, Hwang SJ. Physicochemical properties and oral bioavailability of amorphous atorvastatinhemi-calcium using spray-drying and SAS process. Int J Pharm. 2008;359:211–9.
  1. Patel M, Tekade M, Gattani S, Surana S. Solubility Enhancement of Lovastatin by Modified Locust Bean Gum UsingSolid Dispersion Techniques.AAPS PharmSciTech, Dec 2008;9(4):9171-4.
  1. Shavi GV, Averineni RK, Usha YK, Armugam K, Ranjan OP, Ginjupalli K et al. Enhanced dissolution and bioavailability of gliclazide using solid dispersion techniques. Int J Drug Delivery 2010;2:49-57.

9 / Signature of the candidate: / (ALEKHYA NUVVULA)
10 / Remarks of the guide: / RECOMMENDED.
11 / Name And Designation of:
11.1 Guide
11.2 Signature / Dr. SATISH C.S.
Professor and Head,
Department of Pharmaceutics,
P.E.S.College of Pharmacy,
Bangalore-560050.
11.3 Co-Guide
11.4 Signature / NOT APPLICABLE
11.5 Head of the department
11.6 Signature / Dr. S.J.SHANKAR
Professor& Head,
Department of Pharmaceutical technology,
P.E.S.College of Pharmacy,
Bangalore -560050.
12 / 12.1 Remarks of the Chairman and Principal:
Prof. Dr. S. MOHAN,
Principal,
P.E.S.College of Pharmacy,
Bangalore-560050.
12.2 Signature :

1