Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

1391270670 (1)


Published on


Published in: Education, Technology, Business
  • Be the first to comment

  • Be the first to like this

1391270670 (1)

  1. 1. Vol 3, Issue 2, 2014. 1578 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences BIOAVAILBILITY ENHANCEMENT OF ARTESUNATE USING SOLID DISPERSION TECHNIQUES Shaundarya Kumar *1 , Dr.Dinesh Chandra2 , Rakesh Singh3 , Vijay Kumar Singh4 , Usha Rai5 , Vaibhav Prakash Srivastava6 *1 Kamala Nehru Institute of Management & Technology ,Sultanpur ,U.P. 2,3,5 Assit. Professor Kamala Nehru Institute of Management & Technology ,Sultanpur ,U.P. 4 Vishveshwarya Institute of Medical Sciences, G. B. Nagar,U.P. ABSTRACT In the present work, an attempt has been made to enhance solubility and dissolution of poorly water soluble drug, Artesunate by preparing solid dispersions using two hydrophilic polymers namely ,β- cyclodextrin and PEG 6000.Drug carrier solid dispersions were prepared by solvent Physical mixing method. Solid dispersions of Artesunate with β-cyclodextrin and PEG 6000 markedly increase the solubility and dissolution of solid dispersion compared to the free form of Artesunate. The results were compared with marketed tablet of Artesunate. The drug carrier interactions in the solid state were investigated using saturated solubility studies, FTIR spectroscopy, X- ray diffraction and differential scanning calorimeter. The developed formulation overcome and alleviates the drawbacks and limitations of Artesunate sustained release formulations and could possibility be advantageous in terms of increased bioavailability of Artesunate. Keywords: Artesunate, Solid dispersion. Bioavailability enhancement, β-cyclodextrin. INTRODUCTION Bioavailability refers to the rate and extent of the drug absorbed in the systemic circulation after administration. Oral delivery, the most convenient mode of drug administration has certain limitations, the most important being the low bioavailability of certain drugs. Drugs having low bioavailability require to be administered at a higher dose as only a small fraction of the administered dose is absorbed in the systemic circulation and reach the target site. 1 WWOORRLLDD JJOOUURRNNAALL OOFF PPHHAARRMMAACCYY AANNDD PPHHAARRMMAACCEEUUTTIICCAALL SSCCIIEENNCCEESS VVoolluummee 33,, IIssssuuee 22,, 11557788--11559955.. RReesseeaarrcchh AArrttiiccllee IISSSSNN 2278 – 4357 Article Received on 17 November 2013, Revised on 20 December 2013, Accepted on 08 January 2014 *Correspondence for Author: Dr. Saundarya kumar Kamala Nehru Institute of Management & Technology, Sultanpur ,U.P., India.
  2. 2. Vol 3, Issue 2, 2014. 1579 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences Absolute bioavailability measures the availability of the active drug in systemic circulationafter non-intravenous administration (i.e., after oral, rectal, transdermal, and subcutaneous administration). In order to determine absolute bioavailability of a drug, a pharmacokinetic study must be done to obtain a plasma drug concentration vs time plot for the drug after both intravenous (i.v.) and non-intravenous administration. This measures the bioavailability of a certain drug when compared with another formulation of the same drug, usually an established standard, or through administration via a different route. When the standard consists of intravenously administered drug, this is known as absolute bioavailability.2 Artesunate is indicated for the treatment of uncomplicated cases of malaria due to Plasmodium falciparum strains which are susceptible to artesunate. The most recent official guidelines on the appropriate use of antimalarial agents and local information on the prevalence of resistance to antimalarial drugs must be taken into consideration for deciding on the appropriateness of therapy with Artesunate. According to current WHO recommendations, oral artesunate should be used as first line therapy for uncomplicated falciparum malaria in combination with amodiaquine, sulfadoxine+pyrimethamine, or mefloquine. 4-5 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 drug can be dispersed molecularly, in amorphous particles (clusters) or in crystalline particles Therefore, based on their molecular arrangement, six different types of solid dispersions can be distinguished. They are described in Moreover, certain combinations can be encountered, i.e. in the same sample; some molecules are present in clusters while some are molecularly dispersed. 6-8 The effect of the particle size of the drug on their dissolution rates and biological availability was reviewed comprehensively by Fincher. For drugs whose GI absorption is rate limited by dissolution reduction of the particle size generally increases the rate of absorption and or total bioavailability. This commonly occurs for drugs with poor water solubility. For example the therapeutic dose of Griseofulvin was reduced to 50% by micronization and is also produced a more constant and reliable blood level. Such enhancement of drug absorption could further be increased several fold if a micronized product was used. Reduction of particle size can be easily and directly accomplished by the first four methods and the resultant fine particles may
  3. 3. Vol 3, Issue 2, 2014. 1580 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences not produce the expected faster dissolution and absorption. Another inherent disadvantage of these pure fine powders of poorly soluble drugs is their poor wettability in water. The significance of the solid dispersion technique was strengthened by the demonstration of Chiou and Riegelman of the fast and almost complete absorption of the insoluble Griseofulvin in man and dogs while the ommercial micronized Griseofulvin was incompletely absorbed (30 – 60 %). They used polyethylene glycol6000 as a dispersion carrier. The main advantages of using water soluble polymers as carriers are their no toxicity and general applicability to most drugs. The main advantages of using water –soluble polymers as carriers are their no toxicity and general applicability to most drugs. 9 Cyclodextrins are bucket-shaped oligosaccharides produced from starch. As a result of their molecular structure and shape, they possess a unique ability to act as molecular containers by entrapping guest molecules in their internal cavity. The resulting inclusion complexes offer a number of potential advantages in pharmaceutical formulations. Cyclodextrins are crystalline, nonhygroscopic, cyclic oligosaccharides derived from starch. Cyclodextrins are used to form inclusion complexes with a variety of drug molecules resulting primarily in improvements to dissolution and bioavailability due to enhanced solubility and improved chemical and physical stability. 10 Methods employed to improve dissolution rate of drugs increasing the surface area a. Micronization or particle size reduction. b. Use of surfactants (to increase surface area by proper wetting). c. Solid dispersions using highly water soluble carriers11 Method of preparation of solid dispersion Sekiguchi et al., (1961) reported the formulation of eutectic mixture that leads to enhancement of solubility of water soluble drugs and thereby bioavailability. 1. Co-precipitation-Most widely used method in the laboratory. Polymers is dissolved in water and the guest is added while stirring the Polymer solution. The precipitate can be collected by decanting, centrifugation or filtration. The precipitate may be washed with small amount of water or other water miscible solvent such as ethyl alcohol, methanol or acetone and dried. 12
  4. 4. Vol 3, Issue 2, 2014. 1581 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences 2. Kneading Technique - Polymer can be added to water as high as 50-60% solids and stirred. The aqueous phase will be saturated with the Polymer in solution. Guest molecules will complex with the Polymer in solution and, as the Polymer complex saturates the water phase, the complex will crystallize or precipitate out of the aqueous phase, and complex can be collected in the same manner as with the co-precipitation method. 13 3. Dry mixing - some guests can be complexed by simply adding guest to the Polymer and mixing them together. The amount of mixing time required is variable and depends on the guest. The method is performed at ambient temperature. 4. Paste complexation - This is a variation of slurry method. Only a small amount of water is added to form a paste, which is mixed with the Polymer using a mortar and pestle. The amount of time required is dependent on the guest. The resulting complex can be dried directly or washed with a small amount of water and collected by filtration and centrifugation. 14 MATERIALS AND METHODS Materials 1. Drug – Artesunate 2. β-cyclodextrin 2. Polyethylene glycol 6000. 3. Methanol. 4. Potassium dihydrogen phosphate. 5. Sodium hydroxide. 6. Distilled water. Instruments 1. Electronic single pan balance. 2. Water bath. 3. Desiccators. 4. Digital tablet dissolution test apparatus – 5. UV spectrophotometer – shimadzu – UV -1700. 7. X-RD (IIT. Ropar) 8.I.R..
  5. 5. Vol 3, Issue 2, 2014. 1582 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences PREPARATION OF SOLID COMPLEXES Complexes of ART & β-CD, ART with β-CD & PEG-6000 were prepared in the molar ratio of 1:1(on the basis of phase solubility study) by different methods like Physical mixing, Kneading,and Fusion method.). Physical Mixture Physical mixture was prepared by triturating ART & β -CD, ART with β -CD & PEG-6000 together for 30 min in a clean and dry glass mortar until a homogeneous mixture was obtained. And then was forced through sieve no 100. Kneading Method ART & β -CD, ART with β -CD & PEG-6000 was mixed separately in glass mortar along with water to obtain a homogeneous paste. The drug (either in powder form or as solution with minimum quantity of methanol) was then slowly added to the paste and the mixture was triturated for 1 hr. during the process the water content was empirically adjusted to maintain the consistency of the paste. Methanol was added to assist dissolution of ART during the process. The paste was dried at room temp., pulverized and forced through sieve no 100. Fusion Method ART and β-CD, ART with β-CD & PEG-6000 were thoroughly mixed and placed in a sealed container with a small amount of water. The contents are heated to about 1000C and then removed and dried. The mass was then pulverized and forced through sieve no 100. The composition of solid dispersion shown in table 1. 18-23 Table N. 1. Composition of solid complexes by using ART & β-CD Type of formulation ART:β -CD (molar ratio) Solid dispersion Method Media APM 1:1 Physical Mixing …….. AKW 1:1 Kneading Water AKM 1:1 Kneading Methanol + Water AFW 1:1 Fusion Water
  6. 6. Vol 3, Issue 2, 2014. 1583 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences 1. STANDARD CALIBRATION CURVE FOR ARTESUNATE IN PHOPHATE BUFFER preparation of phosphate buffer solution -ph 6.8 13.61 grams of potassium dihydrogen phosphate and 3.128 grams of sodium hydroxide were dissolved in 2 liters of distilled water. Procedure 100 mg Artesunate pure drug was taken into a 100ml standard flask and dissolved in distilled water. The volume of stock solution was made up to 100 ml with distilled water. From the above stock solution, 10 ml was transferred into a 100 ml volumetric flask and volume was adjusted to 100 ml that corresponded to 100 µg/ml Artesunate in solution. From that solution different aliquots of 0.2, 0.4, 0.6, 0.8, and 1.0 ml were transferred to 10ml volumetric flask, volume was adjusted with distilled water, which gave a concentration of 2, 4, 6, 8,10 and 12 µg/ml of final standard solution and absorbance of final standard solution was measured at 251.8 nm.The data are given in table 2. 25-29. Table. 2: U.V.spectrophotometric data of artesunate Concentration (ppm) Absorbance* 0 0 1 0.050 2 0.103 3 0.156 4 0.209 5 0.259 6 0.312 7 0.365 8 0.425 9 0.485 10 0.565 RESULTS AND DISCUSSION PREPARATION OF SOLID DISPERSION ART & β -CD, ART with β -CD & PEG-6000 was mixed separately in glass mortar along with water to obtain a homogeneous paste. The drug (either in powder form or as solution with minimum quantity of methanol) was then slowly added to the paste and the mixture was triturated for 1 hr. during the process the water content was empirically adjusted to maintain
  7. 7. Vol 3, Issue 2, 2014. 1584 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences the consistency of the paste. Methanol was added to assist dissolution of ART during the process. The paste was dried at room temp., pulverized and forced through sieve no 100. STANDARD CURVE The standard curve relating the absorbance and concentration of Artesunate (Table No-2, Figure No-1) was used to estimate the concentration of Artesunate released from the solid dispersion formulations and from the marketed samples of Artesunate. Fig :1. Calibration Curve of Artesunate In Phophate Buffer 7.4 DIFFERENTIAL SCANNING COLORIMETRY(DSC) The DSC thermogram of the drug depicts a sharp endothermic peak at 161.82° corresponding to the melting transition temperature of Artesunate. The DSC thermo gram of Artesunate shown in Fig.2. MASS SPECTRUM: A fast atomic bombardment mass spectrum (FAB-MS) of ART was obtained on a JEOL SX-102 spectrometer. The mass spectrum of ART clearly indicates the exact molecular weight as of ART (Figure 3). Fig:2. DSC Thermogram of Pure Artesunate
  8. 8. Vol 3, Issue 2, 2014. 1585 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences Fig:3. Mass spectra of Artesunate FOURIER-TRANSFORM INFRARED SPECTROSCOPY The FTIR spectra were obtained by using an FTIR spectrometer – 430 (JASCO, Japan).The sample (Artesunate, Polymer) were previously ground and mixed thoroughly with potassium bromide in the ratio1:1.5 (Sample: KBr) respectively. The scanning range was 4000 to 400 cm-1. FTIR spectrum of pure drug Artesunate & complex shown in fig 4,5. Fig. 4..FTIR spectrum of pure drug Artesunate Figure 5.FTIR spectrum of APM (ART with β—CD complex prepare by physical mixing).
  9. 9. Vol 3, Issue 2, 2014. 1586 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences Drug Content First of all, the actual drug content in each formulation was determined. The results are reported in Table 3,. As can be seen, all the formulation showed a good agreement between theoretical and actual drug content. The comparison of drug content of different formulation shown in fig 6. Table 3. Drug content of ART+ β-CD complexes (% Drug content) Formulation Theoretical drug content in 100mg Practical drug content in 100mg (mean n=3) % Drug content APM 27.64 27.02 97.75 AKW 27.64 26.93 97.43 AKM 27.64 27.06 97.15 ASE 27.64 27.08 97.98 AFU 27.64 27.11 98.08 Figure.6. comparison of % Drug content drug content of different formulation SATURATION SOLUBILITY OF DIFFERENT FORMULATIONS OF ARTESUNATE. The saturation solubility of pure ART and its complexes with β -CD is shown in table 4. The saturation solubility of pure ART is 11.9µg/ml while the saturation solubility of all other complex prepared by various methods exhibited dramatic increase in the saturation solubility. APM and PEG-6000 (complex prepared by physical mixing) showed a lower value for
  10. 10. Vol 3, Issue 2, 2014. 1587 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences saturation solubility than that of other complexes, the low saturation solubility can be attributed to poor complexation efficiency during physical mixing. Table4. Saturation solubility data of different formulation of Artesunate with β-CD Formulation Saturation solubility (µg/ml) Pure ART 11.95 ± 0.84 APM 78.90 ± 2.11 AKW 135.78 ± 2.31 AKM 141.47 ± 2.67 ASE 104.99 ± 2.67 AFU 119.82 ± 2.48 Mean saturation solubility ± SD (n=3) X-RAY DIFFRACTOMETRY The X-ray diffractometry (XRD) pattern of Artesunate and its various complexes with β-CD & ART, β-CD & PEG -6000 are shown fig 7-8 (peak search data). The XRD pattern of Artesunate has sharp peak at different angle (2θ) higher intensity 6.72 θ, 14.17θ, 18.97 θ, 22.18 θ, 25.85θ show a tripical crystalline pattern showed diffraction peaks with a higher number of reflections of higher intensity indicating a crystalline structure. The spectrum of β- CD reveled fewer number of very poor intensity reflections corresponding to inter planner distance of 9.7, .6.0, 5.7, 4.9,3.3 Å at 57.81, 30.78,41.27,32.05 and 20.270 respectively. Fig 7. XRD pattern (raw data) of Pure Artesunate
  11. 11. Vol 3, Issue 2, 2014. 1588 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences Fig 8. XRD Pattern of APKW (ART with β-CD &PEG-6000 complex prepared by kneading method employing water as solvent CHARACTERIZATION OF PREPARED TABLETS. Table 5. Characterization of prepared tablets of different complexes by using β-CD Formulation Average wt (mg) Thickness (mm) Hardness (Kg/cm2) Percentage friability Disintegration time (sec) Pure Artesunate 200 ± 5.24 3.74 ± 0.08 5.56 ± 0.17 0.632 282 APM 200 ± 7.11 3.72 ± 0.05 5.61 ± 0.18 0.624 260 AKW 200 ± 6.47 3.94 ± 0.04 5.41 ± 0.15 0.645 224 AKM 200 ± 6.71 3.91 ± 0.02 5.35 ± 0.18 0.671 210 ASE 200 ± 5.78 3.81 ± 0.09 5.29 ± 0.13 0.682 296 AFU 200 ± 6.73 3.96 ± 0.11 5.22 ± 0.14 0.667 301 Mean ± S.D.; (n=20) (n=10) (n=10) (n=10) (n=10) IN VITRO DRUG RELEASE Different formulations of ART were compressed into tablets as per the composition given in table 6. the tablet thickness and hardness were in the range of 3.6-3.8 mm and 5-6 Kg/cm2, respectively. Fig.9, show in-vitro drug release profile of different formulations of Artesunate in tablet form. Pure Artesunate was characterized by only 56% drug release within 100 min in phosphate buffer (pH 7.4) Physical mixtures presented slight improvement in drug release
  12. 12. Vol 3, Issue 2, 2014. 1589 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences and saturation solubility this could be attributed to the improved wetability of drug particles by the physical presence of β-cyclodextrins. Table.6 : Dissolution profile of different formulation of ART & β-CD in phosphate buffer 7.4 Time(min) %DrugReleasefromtheformulations(mean;n=3) ART APM AKW AKM ASE AFU 0 0 0 0 0 0 0 10 10.52 13.17 32.43 40.43 25.17 28.34 20 15.52 18.22 41.23 48.13 41.23 40.13 30 20.27 26.12 55.12 65.14 55.48 49.24 40 22.4 30.1 65.1 75.24 64.12 58.12 50 26.52 35.23 72.13 82.12 69.4 65.15 60 31.43 40.43 78.24 92.21 72.43 73.23 70 35.54 45.15 82.02 94.1 74.13 76.12 80 38.42 50.13 84.13 96.12 78.55 81.13 90 42.53 55.12 86.31 97.13 80.1 85.41 100 45.53 61.44 88.14 97.85 84.15 90.11 Fig 9, Graph of Dissolution profile of different formulation of ART with β-CD. Mean dissolution time. In order to calculate mean dissolution time (MDT) of pure Artesunate, its physical mixture, and complexes with β-CD, & β-CD with PEG-6000 the mean (n=3) of cumulative drug
  13. 13. Vol 3, Issue 2, 2014. 1590 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences release (µg) was used. The obtained values of MDT for all the formulations are presented in table 7and fig 10. Table 7. Mean dissolution time of different ART β-CD, & ART β-CD with PEG-6000 complex formulations. Formulation Mean dissolution time(min) ART 38.10 APM 34.78 APPM 34.20 AKW 21.52 APKW 18.63 AKM 14.36 APKM 12.84 ASE 28.12 APSE 27.13 AFU 30.92 TPFU 33.43 Fig.10. Mean dissolution time of different ART β-CD, & ART β-CD with PEG-6000 complex formulations FORMULATION STABILITY STUDY Based on the result of initial characterization the kneaded formulations (AKM, and APKM) were thought to be the superior formulations and hence were subjected to accelerated stability study.
  14. 14. Vol 3, Issue 2, 2014. 1591 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences Table. 8. Dissolution data of AKM & APKM during stability study at Different time intervals. Time %DrugReleasefromtheformulations(mean;n=3) Initial After3months AKM APKM AKM APKM 0 0.00 0.00 0.00 0.00 10 40.43 40.48 36.38 46.58 20 48.13 48.18 57.84 52.14 30 65.14 65.12 69.13 68.23 40 75.24 74.82 72.42 77.53 50 82.12 81.13 75.10 85.12 60 92.21 90.1 76.23 89.43 70 94.1 93.23 78.12 90.93 80 96.12 95.25 80.92 92.94 90 97.13 97.25 82.71 94.21 100 97.85 98.37 84.24 95.11 Fig. 11. Dissolution profile of ART & APKM during stability study Table 9. Physical properties of batches kept for stability studies. BATCH 0 DAYS 30DAYS DT (Sec) FRIABILITY (%) ASSAY (%) DT (Sec) Percentage friability ASSAY (%) Pure Artesunate 24 0.632 96.34% 24 0.632 97.34% APPM 29 0.622 103.15% 28 0.622 102.15% APKW 22 0.641 102.7% 23 0.641 101.7% APKM 23 0.667 101.4% 99.4% APSE 22 0.683 98.62& 97.99% APFU 28 0.665 99.21% 99.21%
  15. 15. Vol 3, Issue 2, 2014. 1592 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences DISCUSSION The phase solubility study showed that the solubility of Artesunate increases linearly as a function of β-CD and PEG-6000 over the entire concentration range and was characteristic of the AL type of curve and it suggests that water-soluble complex was formed in solution. Solubility studies showed a significant, linear increase in the aqueous solubility of the Artesunate with increasing concentration of β-CD, maximum concentration of β-CD (15mM/L) so improvements in the saturation solubility of Artesunate. The complex of Artesunate with β-CD & PEG-6000 prepared successfully by the physical mixing, kneading, solvent evaporation and fusion methods in the molar ratio of 1:1. This was confirmed by FTIR and XRD studies. These in all five method employing kneading method using methanol-water as solvent employing exhibited the fastest and highest in vitro dissolution rate when compared to the tablet of pure Artesunate, and during stability study there was very slight decrease in its dissolution profile. Cyclodextrins (CDs) improve solubility significantly they are still limited in their drug inclusion capacity and retain disadvantageous processing characteristics for oral dosage forms; the volume of CD complexes is often much greater than the volume of drug alone, which may severely limit the types of delivery technologies that may be employed The saturation solubility of the drug in the freeze-dried complex and spray-dried complex was increased to 29.33±1.08 mg/ml and 28.76±0.56mg/ml respectively A very high increase of the drug dissolution rate was found in case of freeze-dried and spray-dried product due to the formation of soluble inclusion complex, amorphisation of the drug and consequently solubility increase and better wettability. CONCLUSION Thus it can be concluded that Artesunate should contain a stabilizing agent to protect its conversion in lactone form. Here, β-CD and PEG-6000 proved a better stabilizing agent than buffering agent, which not only increased the solubility of the drug but also acts as a stabilizer in drug formulation. Thus the complexation of Artesunate has a dual advantage over the existing formulation. The results of drug content of the physical mixture, kneaded ternary and Fused complexes are in good agreement with the theoretical value. The kneaded ternary showed 101.37%±0.12 of drug due to lesser drug loss as compared to the spray dried ternary which showed drug content of 83.84%±1.11
  16. 16. Vol 3, Issue 2, 2014. 1593 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences ACKNOWLEDGEMENT Words are less to express my deep sense of gratitude to my guide Dr. Dinesh Chandra (HOD) Department of Pharmaceutics, KNIMT,Sultanpur .I would like to thanks Usha for helping me each and every time. My research wouldn't have seen the day's light without their constant motivation. REFERENCES 1. Green M D, Mount D L and Wirtz R A (2001) Authentication of artemether, artesunate and dihydroartemisinin antimalarial tablets using a simple colorimetric method. Trop Med and Int Health 6: 980-982. The International Pharmacopoeia Volume 5, pp. 193- 198, 218-222, 227-228. 2. Zhou Z M, Anders J C, Chung H and Theoharides A D (1987) Analysis of artesunic acid and dihydroqinghaosu in blood by high-performance liquid chromatography with reductive electrochemical detection. J Chromatogr Biomed Appl 414: 77-90. 3. Liu H, Li Q, Li S, Zou Y, Gu A (2008) The Rapid Determination of Artemisinin by Post-Column Derivatization High-Performance Liquid Chromatography Using Matrix . 4. Gillio-Tos M V, Previtera S A and Goodman E M (1964) Spectrophotometric determination of 2-phenylindole with p-dimethylaminobenzaldehyde. Analytical Chemistry 36:425-426. 5. Adegoke O A and Nwoke C E (2008) Spectrophotometric determination of Hydralazine using p-dimethylaminobenzaldehyde. J Iran Chem Soc 5:316-323. 6. Attaran A, Barnes KI, Curtis C: The global fund and medical malpractice in malaria treatment. Lancet 2004, 363, 237–240. 7. Rowland M, Durrani N, Hewitt S, Sondrop E: Resistance of falciparum malaria to chloroquine and sulfadoxinepyrimethamine in Afghan refugee settlements in western Pakistan: Survey by the general health services using a simplified in vivo test. Trop Med Int Health 1997, 2, 1049–1056. Vector borne diseases in Pakistan, Country report of Pakistan. Khartoum, Sudan 2003, 1–11. 8. Bradley D, Brannister B: Guidelines for malaria prevention in travellers from the United Kingdom for 2001. Common Dis Publ Health 2001, 84–101. 9. Sweetman S: Martindale: The Complete Drug Reference. Royal Pharmaceutical Press, London. 10. Woodrow CJ, Haynes RK, Krishna S: Artemisinin. Postgrad Med J 2005, 81, 71–78.
  17. 17. Vol 3, Issue 2, 2014. 1594 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences 11. Famin O, Ginsburg H: Differential effects of 4-aminoquinoline-containing antimalarial drugs on hemoglobin digestion in plasmodium falciparum-infected erythrocytes. Biochem Pharmacol 2002, 63(3), 393–398. 12. Min-Young Heo, Zong-Zhu Piao, Tae-Wan Kim, Qing-Re Cao, Aera Kim, Beom Jin Lee: Effect of solubilizing and microemulsifying excipients polyethylene glycol 6000 solid dispersion on enhanced dissolution and bioavailability of ketokonazole. Arch Pharm Res 2005, 28 (5), 604–611. 13. Sethia S, Squillante E: Solid dispersion of carbamazepine in PVP by conventional solvent evaporation and supercritical methods. Int J Pharm 2004, 272, 1–10. 14. Emara LH, Badr RM, Elbary AA: Improving the dissolution and bioavailability of nifedipine using solid dispersions and solubilizers. Drug Dev Ind Pharm 2002, 28(7), 795–807. 15. Van Nijlen T, Brennan K, Van den Mooter G, Blaton N, Kinget R, Augustijns P: Improvement of the dissolution rate of artemisinin by means of supercritical fluid technology and solid dispersions. Int J Pharm 2003, 254 (2), 16. Sanjay kumar dash, K. Sekiguchi, and N. Obi, “Studies on absorption of eutectic mixture” I. A comparison of the behavior of eutectic mixture of sulfathiazole and that of ordinary sulfathiazole in man,” Chem. Pharm. Bull., vol. 9, 1961, pp. 866-872. 17. Sunita Kumari*, Sharad Visht, Pramod kumar Sharma Preparation and Evaluation of Fast Disintegrating Tablets of Dicyclomine HCl .Institutional affiliation of authors: Deptt. of Pharmaceutical Technology Meerut Institute of Engineering.& Technology, NH-58, Near Baghpat bypass crossing, Meerut-250005 U.P. India.2010. 18. Behnaz Esmaeili a,b,c, Zahra Basseda a,b,c, Ahmad Reza Dehpour a,b,Antagonism of muscarinic M1 receptors by dicyclomine inhibits the consolidation of morphine- associated contextual memory Brain Research Bulletin 76 (2008) 380–387 19. Vikas Jain and Ranjit Singh Dicyclomine-loaded Eudragit®-based Microsponge with Potential for Colonic Delivery: Preparation and Characterization School of Pharmaceutical Sciences, Shobhit University, Meerut, Uttar Pradesh, 250110, India 20. Ammanage et al. Dicyclomine hydrochloride, Eudragit E-100, Oral disintegrating tablets, Super disintegrating agents, Taste masking. Vol. 4, Suppl 1, 2011 21. Alka Tomar , Kiran Sharma, Nitesh S Chauhan*, Ashu Mittal, Umakant Bajaj(Formulation and Evaluation of Fast Dissolving Oral Film of Dicyclomine as potential route of Buccal Delivery) Department of Pharmaceutics, KIET School of Pharmacy, Ghaziabad 2012
  18. 18. Vol 3, Issue 2, 2014. 1595 Shaundarya Kumar et al. World Journal of Pharmacy and Pharmaceutical Sciences 22. Ahire B. R., Rane B. R., Bakliwal S. R., Pawar S. P. Solubility Enhancement of Poorly Water Soluble Drug by Solid Dispersion Techniques Vol.2, No.3, July-Sept 2010 pp 2007-2015, 23. SP. Dhat, SA. Aphale, AP. Sherje, JA. Sakale, AV. Vaidya and SD. Vanshiv Department of Pharmaceutics, Sinhgad Institute of Pharmacy, Narhe, Pune, Maharashtra, India. Solubility Enhancement of Satranidazole Using Solid Dispersion Technique Vol. 2 (3) Jul – Sep 2011. 24. S.Muralidhar, G.Devala Rao, M.Krishna Murthy, K.Kiran Kumar,( Enhancement of dissolution rate of etoricoxib through solid dispersion technique) K.Kranthi Teja,Syed Khaja Nawaj,T.V.Narayana 10-07-2011. 25. Gupta et al .( Enhancement of Dissolution rate of ibuprofen by preparing Solid dispersion using different method)Dept. of Pharmaceutics, Jaipur College of Pharmacy, RIICO Institutional Area, Tonk Road, Sitapura, Jaipur , Rajasthan (India.)302022, 2 Dept. of Mathematics and Statistics, Banasthali University, Banasthali (Newai), Rajasthan 304022. Vol 3 Suppl 3, 2011 26. V. Tomar1, N. Garud1, P. Kannojia1, A. Garud1, N. K. Jain2, N. Singh2. Enhancement of Solubility of Acyclovir by Solid Dispersion And Inclusion Complexation Methods 1Institute of Professional Studies, Shivpuri Link Road, Gwalior, M.P., India 2Pranav Institute of Pharmaceutical science and research, Gwalior, M.P.,- India 2010. 27. Prashant Upadhyay 1 Formulation of Fast-Release Gastroretentive Solid Dispersion of Glibenclamide with Gelucire 50/13Department of Pharmaceutics, College of Pharmacy, I.F.T.M, Delhi Road, Moradabad-244001 and Gautam Buddh Technical University, Lucknow 28. Veerendra S. Rajpurohita, Pankaj Rakhaa, Surender Goyala, Harish Durejab, Formulation and Characterization of Solid Dispersions of Glimepiride through Factorial Design Gitika Arorac and Manju Nagpald, aRajendra Institute of Technology and Sciences, Hisar Road, Sirsa-125055, India .Department of Pharmaceutical Sciences, M. D. University, Rohtak- 124001, India 2011 29. Hassan Sadraeia, Golamreza Asghari b, Mostafa Shamsa, b Antidiarrhoeal Action of Hydroalcoholic Extract of Pycnocycla spinosa in Comparison with Loperamide and Dicyclomine a Department of Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran Van Den Mooter G, Wuyts M, Blaton N, et al. Physical stabilization of amorphous ketoconazole in solid dispersions with polyvinylpyrrolidone K25. Eur J Pharm Sci. 200;12(3):261-269.