INTRODUCTION:

Ascariasis, a parasitic infection caused by Ascaris lumbricoides, remains a major public health concern, especially in areas with poor sanitation. Mebendazole is a widely used anthelmintic drug for treating this condition due to its effectiveness against a variety of intestinal worms. However, its low water solubility and limited oral bioavailability hinder its therapeutic efficacy.

Formed Mebendazole-loaded microsponges enhance its intestinal permeability, oral bioavailability, and therapeutic performance. The pH sensitive nature of Eudragit S100 polymer helps in effective targeting of microsponges in colon. Microsponges are porous polymeric structures with a high degree of cross-linking, featuring numerous interconnected spaces that can encapsulate active ingredients and release them in a controlled manner. These microsponges, which vary in size from 5 to 300 µm, are designed to achieve a sustained drug release profile, potentially offering superior treatment outcomes for ascariasis compared to conventional Mebendazole formulations.^1-3

MATERIAL AND METHODS:

Materials:

Mebendazole, Eudragit S100, Dichloromethane, 0.5M methanoic hydrocloride, Polyvinyl Alcohol, Dibutyl phthalate.

Preparation of Mebendazole loaded Microsponges:

Eudragit S 100 was used as the polymer in the mebendazole-loaded formulation, which was made utilizing the quasi-emulsion solvent diffusion approach. Eudragit S 100 was dissolved in a 1:1 ethanol-dichloromethane mixture (20ml). To this mixture Mebendazole was added and sonicated for a few minutes. Dibutyl phthalate (0.1% v/v) was then incorporated to provide plasticity to the microsponges (internal phase). Separately, 500mg of polyvinyl alcohol was dissolved in distilled water and heated to obtain a clear solution. Solvent evaporated to form microsponge, the organic phase was then added dropwise to the external phase and agitated for six hours at 800 rpm using a mechanical stirrer. Formed micro sponges were separated by filtering and then dried for 48 hours at 40°C in an air-heated oven.^4-6

Table I: Composition of trial batches of MBZ Microsponges

Batches	B-1	B-2	B-3	B-4	B-5	B-6
Mebendazole (mg)	100	100	100	100	100	100
Eudragit S 100 (mg)	100	200	300	400	500	600
Ethanol: DCM (ml)	10:10	10:10	10:10	10:10	10:10	10:10
Dibutyl phthalate (ml)	0.1	0.1	0.1	0.1	0.1	0.1
Polyvinyl Alcohol (mg)	500	500	500	500	500	500
Water (ml)	100	100	100	100	100	100

Optimization of Formulation Parameters:

Design expert software 13 were used and selected factors were drug, polyvinyl alcohol and solvent. To determine the impact of drug, polyvinyl alcohol and solvent were selected for independent factors and the different levels based on initial trial.⁷

Characterization and evaluation optimized batch:

Product yield:

Yield was calculated by using following formula.⁸

Practical mass of Microsponges

Production Yield: ---------------------------- X 100

Theoratical mass (Drug + Polymer)

Drug Content:

Drug content calculated by dissolving 10mg of Mebendazole microsponges in 10milliliters of 0.5M methanoic hydrochloride, the drug conce. A magnetic stirrer was used to agitate the formed mixture, and Whatman filter paper was used to filter it. Using spectrophotometry, the drug content was determined at 233nm. Drug content was determined by dissolving 10 mg of Mebendazole microsponges in 10ml of 0.5M methanoic hydrochloride. Formed mixture was stirred using a magnetic stirrer and filtered by using whatman filter paper.⁹

Actual drug content

Drug Content =------------------------- x 100

Qty. of microsponge

Entrapment Efficiency:

Entrapment efficiency determine by using a 10ml dispersion of microsponges which was centrifuged at 4000rpm. After centrifugation, microsponges settled at the bottom, and the supernatant was collected. A 1ml sample of the supernatant was withdrawn, diluted to 10 ml with distilled water and measured spectrophotometric ally at 233.4nm. Entrapment efficiency was calculated using the calibration curve of Mebendazole in water.⁹

Actual drug content

Entrapment Efficiency = ---------------------------- x 100

Theorotical drug content

Particle Size Analysis:

Particle size of Microsponge was used carried out with help of optical microscope. For each batch of microsponge, 20 microsponge were used to determine the average particle size.¹⁰

Surface Morphology:

Surface topography, prepared microsponges were examined with a scanning electron microscope. Samples holder having double-sided tape with an acceleration voltage of 10kV.¹¹

Infrared spectroscopy:

FTIR spectra of Mebendazole API and microsponge formulation were recorded in wavelength range of 4000 to 400 cm^-1.¹²

Differential scanning calorimetry (DSC):

DSC was performed to assess the thermal behaviour of the drug and excipients. weighed sample was sealed in aluminium pans followed by heating of flow 10°C/min over a temperature range of 0°C to 300°C

XRD:

PXRD analysis of the microsponge was performed by using XRD model (Bruker AXS D8) with continuous at 2θ angle position.¹⁴

Stability Studies:

To evaluate the chemical and physical stability of the optimized batch (F-5) of microsponges loaded with MBZ, a stability analysis was carried out. Stability study conducted for three months at 25°C±60% RH and 40°C ±75% RH. Samples of the MBZ-loaded microsponges were evaluated at intervals of 1, 2, and 3 months.¹⁵

Evaluation of MBZ loaded Microsponge Tablet:

Precompression Study of MBZ Loaded Microsponge Tablet:

A weighed quantity of powder was put into a graduated cylinder, and its initial volume (V0) was measured in order to calculate the bulk density and tapped density. The density setting was adjusted, and the final volume (Vf) was recorded after packing. Bulk density and tapped density calculated using following formula

W/V0 was used to compute the bulk density W/V0, and tapped density as W/Vf.

Where W is the powder's weight, V0 is its beginning volume, and Vf is its final volume.¹⁶

In-Vitro Drug Release Study:

In-vitro drug release investigation was performed using 900ml of 0.1 N HCl, phosphate buffer pH 6.8, and phosphate buffer pH 7.4. Test was run at 50rpm and 37± 0.5°C temperature.¹⁸

Comparative study:

To compare the formulated microsponge tablet to the marketed tablet and determine which was more successful, an in-vitro dissolution study was carried out.

Drug release Kinetic Study:

A number of kinetic models, including zero-order, first-order, Higuchi's, Korsmeyer-Peppas, and Hixson-Crowell models were used to analyse the data from the in-vitro dissolution investigation. Regression analysis of the corresponding plots was used to determine the coefficient of correlation (r) values for the linear curves.¹⁹

RESULT AND DISCUSSION:

Optimization of Formulation Parameters.

Effect of Dependent Factors on entrapment efficiency:

Fig. 1: 3D surface showing an impact of independent variable on entrapment efficiency

A significant model (p<0.0001) is indicated by the model F-value of 55.60. Logically, the corrected R2 of 0.9685 and the expected R2 of 0.8393 agreed. Finally, the model's ability to direct the design space was demonstrated by the precision of 27.6894, which showed a design space.

Coded equation:

EE=73.266+0.67375 A+0.95375 B+0.175C+8.6025AB - 6.99AC+2.09 BC+3.30325 A² -5.67175B²+4.18575C²

Drug (A), solvent (B), and polyvinyl alcohol (C) show positive coefficients, suggesting that raising their concentrations will improve the efficiency of trapping. Entrapment efficiency is positively impacted by the drug-solvent (AB) interaction, but negatively by the drug-PVA (AC) interaction. This might be explained by the medication's hydrophobic properties, which may lead to poor interaction or competition for binding sites within the polymer matrix, resulting in reduced entrapment efficiency. The interaction between solvent and PVA (BC) also positively affects entrapment efficiency.²⁰

Production yield:

Fig. 2: 3D surface showing an impact of independent variable on production yield

A significant model (p < 0.0001) is indicated by the model F-value of 52.61. Logically, the corrected R2 of 0.9967 and the projected R2 of 0.7669 agreed. Finally, the model's ability to direct the design space was demonstrated by the precision of 25.4815, which showed a sufficient signal.

Coded equation:

PY=85.6 + 1.12125A + 1.12875B - 0.75 C - 1.2575AB + 1.5AC - 2BC + 4.07875A² -3.92125B² - 0.6787 C²

Effect of Dependent Factors on production yield:

Drug (A) and solvent (B) show positive coefficients, indicating that increasing their concentrations will enhance production yield. However, PVA (C) shows a negative effect on production yield, possibly due to its tendency to increase viscosity, which complicates processing and reduces yield. The interaction between drug and PVA (AC) positively impacts production yield, while the interaction between drug and solvent (AB) has a negative effect, possibly due to oversaturation or viscosity changes. Similarly, the interaction between solvent and PVA (BC) negatively affects production yield, likely due to high levels of solvent and PVA causing processing difficulties such as excessive viscosity, which reduces yield.²⁰

Table II: Evaluation of Optimization of Batches

Batches	Entrapment Efficiency (%)	Production Yield (%)
B-1	67.92	71.5
B-2	82.87	92
B-3	72.03	85.6
B-4	62.69	87
B-5	57.03	82
B-6	42.90	80

Particle Size Determination:

Using a motic microscope, the optimised microsponges (F-5) particle size was determined. As seen in the image, the particle sizes varied from 14µm to 42µm. and average particle size was found to be 27.37µm.²¹

Fig. 3: Optical Microscopy and Particle Size of Optimized Formulation

547.4

Mean Particle Size = ------- = 27.37 µm

Surface Morphology:

SEM analysis of the optimized microsponges (F-5) revealed their spongy, spherical shape, and uniform appearance.

Fig. 4: Scanning Electron Microscopy of Optimized Formulation

Fourier Transform Infrared Spectroscopy (FTIR)

FTIR spectrum showed all of the distinctive peaks that went along with its functional groups. There was no interaction between the drug and the excipients as shown by the FTIR spectra of physical mixes of MBZ with Eudragit S 100, which displayed the distinct bands of MBZ at their respective wave numbers. With the exception of the C-O group's absence in this interpretation, every functional group found in the pure drug was detected in the optimised formulation's FTIR study.²²

Fig. 5: FTIR of pure drug

Table III: FTIR of Interpretation of pure drug

Functional groups	Peak (cm^-1)
C = O	1642.55
C-N	1268.71
C-O	1085.76
CH3 (Stretch)	2951.62
CH2 (Stretch)	1188.86
N-H	3441.32
C=C	1589.72

Fig. 7: FTIR study Optimized Batch

Table IV: FTIR of Interpretation of optimized formulation

Functional groups	Peak (cm^-1)
C = O	1644.29
C-N	1267.37
C-O	1088.46
CH3 (Stretch)	2951.23
CH2 (Stretch)	1188.40
N-H	3401.49
C=C	1593.08

Differential Scanning Calorimetry:

As shown in figure, thermogram of pure MBZ shows an onset temperature of 223°C with a final endset peak at 328.68°C, indicating complete melting at the MBZ melting point of 288°C. The wide temperature range or buffer zone between 233°C to 262°C and 322°C to 328.68°C is due to the polymorphic nature of MBZ. The formulation's DSC spectra show a noticeable shift in temperature ranges compared to the pure drug, indicated compatibility of the excipients with MBZ.

Fig. 8: DSC of the pure drug

Fig. 9: DSC Study Optimized Formulation

X-ray Diffraction Study (XRD):

Pure mebendazole's XRD spectra showed strong, intense peaks at 7°, 17°, 19°, and 26° (2θ), suggesting that it is crystalline. On the other hand, the optimised batch (F-5) of MBZ microsponges' XRD diffractogram revealed strong, lower-intensity peaks at 7°, 17°, 23°, and 28° (2θ), indicating that the amorphous microsponge formulation.²³

Fig. 10: X-ray diffraction study of pure drug

Fig. 11: X-ray diffraction study of optimized Microsponges

Pre-Compression Study of Optimized Formulation:

Ingredients	Quantity Taken (mg)
MBZ 100 mg microsponges	277.8
Povidone K-30	7
Magnesium Stearate	3.5
Hydroxypropyl Methyl Cellulose	17.5
Microcrystalline Cellulose	44.2
Total	350 mg

In-Vitro Drug Release Study:

The optimized microsponges, both in tablet and marketed formulations, along with the pure drug preparation, underwent dissolution testing in different medium such as 0.1 N HCl, phosphate buffer (pH 6.8, and pH 7.4) to evaluate their in vitro drug release profiles. The results showed that the marketed formulation achieved complete drug release within 1 hour in 0.1 N HCl. In contrast, the MBZ-loaded microsponge formulation exhibited prolonged drug release. Dissolution studies over 9 hours revealed a cumulative drug release of 62.62%, increasing to 89.29% after 24 hours.

The extended release from microsponges is attributed to the pH sensitivity and swelling characteristics of Eudragit S100 polymer. In this formulation, Eudragit S100 forms a matrix that entraps the drug. As the polymer matrix swells, erodes, or dissolves in intestinal fluids, the drug is gradually released, protecting it from the acidic environment of the stomach during fasting. This mechanism ensures consistent drug release over an extended period, reducing the need for multiple daily doses and potentially enhancing efficacy.

Fig. 12: Comparative drug release study

Drug Release Kinetic Study:

The data indicates that drug release from microsponge tablets is primarily governed by diffusion and remains unaffected by the amount of unreleased drug within the tablet. The release profile of Mebendazole-loaded microsponge tablets adheres to the Korsmeyer-Peppas equation, demonstrating a high R² value of 0.9128. This model suggests that the drug release mechanism predominantly involves diffusion, facilitated by the swelling properties of polymer Eudragit.

Model	R² value
Zero order	0.9028
Korsemeyer peppas	0.9128
Higuchi	0.9045
First order	0.8388

Stability Studies:

Stability tests conducted showed that, there were no significant changes observed in the entrapment efficiency or drug loading of microsponges (F-5). Based on these findings, it was concluded that the microsponges formulated for this purpose remained stable for 1 month when stored at room temperature.^{23 -26}

CONCLUSION:

Mebendazole is poorly soluble in water and has a limited bioavailability, it usually needs to be administered often. To address this issue, it was chosen as the model drug for a microsponge-based delivery system that would lower the frequency of dosage and provide regulated release in the colon. Eudragit S100, a pH-sensitive polymer, was added to the microsponges throughout their development using the quasi-emulsion solvent diffusion method, and they were then compacted into tablets. This strategy aims to enhance efficacy against colonic parasites by precisely targeting drug delivery to the colon.

Prior to formulation, comprehensive studies including UV spectroscopy, FTIR analysis, and thermal analysis (DSC) confirmed the characteristics of mebendazole, highlighting its Polymorphic characteristics. The drug's crystalline structure was verified by X-ray diffraction (XRD). Stability testing conducted over 30 days demonstrated no changes, ensuring the purity and stability of the formulation.

Utilizing Box-Behnken Design for optimization, batch (F-5) achieved exceptional results with an entrapment efficiency of 88.26% and a production yield of 90%. Morphological analysis disclosed microsponges that were porous and spherical, with a mean particle size of 27.37 µm. Dissolution studies exhibited controlled release characteristics over 24 hours, validated by the Korsmeyer-Peppas model, which indicates diffusion-controlled release enhanced by Eudragit S100's swelling properties. This innovative approach holds promise for effective colonic delivery, potentially reducing dosing frequency and enhancing therapeutic outcomes against colonic infections.

REFERENCES:

1. Desta A., Anteneh B. and Nisha J.: Formulation, Optimization and In Vitro Evaluation of Solubility Enhanced Fast Disintegrating Tablets of Mebendazole, J Bioequiv Available an open access Journal. 2018: 10(4): 78-83.

2. Braithwaite PA., Roberts MS., Allan RJ. and Watson TR. Clinical pharmacokinetics of high dose mebendazole in patients treated for cystic hydatid disease. Eur J Clin Pharmacol. 1982; 22(2): 161-169.

3. Manisha K. and Pawar A.: Microsponges: A novel strategy for Drug delivery, International Journal of Pure and Applied Biosciences. 2015; 3(1): 224-235

4. Pavani V., Vinod M. and Anantha, P.).: Design, Formulation And In Vitro Evaluation of Microsponges Based Gel for Topical Delivery of Ketoconazole, International Journal of Pharmaceutical Sciences and Research. 2017; 8(10): 4222–4229

5. Pratap Singh R. and Kumar Prajapati S. Formulation And Evaluation of Prednisolone Loaded Microsponges for Colon Drug Delivery: In-Vitro and Pharmacokinetic Study, International Journal of Pharmaceutical Sciences and Research. 2014; 5(5).

6. Zaman M., Qureshi S., Sultana K., Hanif M., Mahmood A., Shaheryar Z. A., Gulzar F., Barkat K. and Abdel-Daim M. M. Application of quasi-emulsification and modified double emulsification techniques for formulation of tacrolimus microsponges, International Journal of Nanomedicine. 2018; 13: 4537–4548.

7. Karmakar S., Poddar S., Khanam J. Understanding the effects of associated factors in the development of microsponge-based drug delivery: a statistical quality by design (QbD) approach towards optimization, AAPS PharmSciTech. 2022; 23(7): 256.

8. Maskare R., Thakre S., Jaiswal A., Chawade, D., Vishwakarma S., Bahekar T. Formulation of Microsponge of Thyme for Acne Treatment. Res. J. Pharm. and Tech. 2013; 16(8): 3767-3772.

9. Sultan F, Chopra H., Sharma G. Formulation and Evaluation of Luliconazole Microsponges Loaded Gel for Topical Delivery. Res. J. Pharm. and Tech. 2021; 14(11): 5775-5780.

10. Rajurkar VG. Topical Anti-Inflammatory Gels of Naproxen Entrapped in Eudragit Based Microsponge Delivery System. J Adv Chem Eng. 2015 Jul 01; 5:1-6.

11. Bhatia M., Saini M. Formulation and evaluation of curcumin microsponges for oral and topical drug delivery. Prog Biomater. 2018; 7(3): 239-248. doi: 10.1007/s40204-018-0099-9.

12. Fatema K., Sajeeb B., Sikdar K.M., Yasif H., Monjur Al. and Bachar S. Evaluation of the Formulation of Combined Dosage Form of Albendazole and Mebendazole through In vitro Physicochemical and Anthelmintic Study. Dhaka University Journal of Pharmaceutical Sciences. 2022; 20: 153-163. 10.3329/dujps. v21i2.63116.

13. Swanepoel E., Liebenberg W., Devarakonda B. and De Villiers M. Developing a discriminating dissolution test for three mebendazole polymorphs based on solubility differences. Die Pharmazie. 2003; 58: 117-21.

14. Shrivastava S. and Kaur C. Fabrication of Mebendazole-loaded solid lipid nanoparticles: Formulation, optimization, characterization, stabilization, and in-vitro evaluation. International Journal of Pharmaceutical Sciences and Drug Research. 2022; 14: 262-268. 10.25004/IJPSDR.2022.140217.

15. United States Pharmacopoeia, 30th edition NF 25-2007. The Official Compendia of Standards. 643, Pharmacopoeial forum 32(1): 141.

16. Baviskar D., Rajput A., Bare K., Biranwar Y., Chaudhari H., Narkhede D., Jain D. Development and in vitro characterization of mebendazole delayed release tablet for colonic drug delivery, Pakistan Journal of Pharmaceutical Sciences. 2014; 27(2):249-53.

17. Dheeraj B., Amarjit R., Kapil B., Yogeshkumar B., Hiralal C., Deepak N., Dinesh J. Development and in-vitro characterization of mebendazole delayed release tablet for colonic drug delivery. Pak J. Pharm. Sci. 2014; 27(2): 249-253.

18. Dash S., Murthy PN., Nath L., Chowdhary P. Kinetic modeling on drug release from controlled drug delivery systems. Acta Pol Pharm. 2010; 67(3): 217-23.

19. Bagul US., Nazirkar MV., Mane AK., Khot SV., Tagalpallewar AA., Kokare CR. Fabrication of architectonic nanosponges for intraocular delivery of Brinzolamide: An insight into QbD driven optimization, in vitro characterization, and pharmacodynamics, International Journal of Pharmaceutics. 2024; 650:123746.

20. Rajurkar VG. Topical Anti-Inflammatory Gels of Naproxen Entrapped in Eudragit Based Microsponge Delivery System. J Adv Chem Eng. 2015; 5:1-6.

21. Fatema K., Sajeeb B., Sikdar K.M., Yasif H., Monjur Al. and Bachar S. Evaluation of the Formulation of Combined Dosage Form of Albendazole and Mebendazole through In vitro Physicochemical and Anthelmintic Study. Dhaka University Journal of Pharmaceutical Sciences. 2022; 20: 153-163.

22. Swanepoel E., Liebenberg W., Devarakonda B., De Villiers MM. Developing a discriminating dissolution test for three mebendazole polymorphs based on solubility differences. Die Pharmazie Int. J. of Pharma.Sci. 2003; 58(2): 117-21.

23. Lavhate K., SolunkeS., Kore K., Shete V., Deshmukh M. Development and Characterization of Mesalamine Microsphere for Colon Specific Drug Delivery. Res. J. Pharm. and Tech. 2020; 13(4): 1747-1751.

24. Ozdemir S., Uner B., Baranauskaite J., Sumer E., Yıldırım E., Yaba A. Design and characterization of dexamethasone loaded microsponges for the management of ulcerative colitis. Eur J. of Pharmaceutics and Biopharmaceutics. 2023; 187:34-45.

25. Kardile SS., Shendge RS., Salunke KS., Wagh OV. Colon-specific tablets containing naproxen microsponges for effective treatment of inflammatory bowel disease. International Journal of Health Sciences. 2022; III: 8419.

26. Nandhakumar S., Sugreevudu G., Harikrishnan N. Formulation design and Evaluation of Extended-Release Tablets of Oxybutynin for Effective Management of Overactive Bladder. Res. J. Pharm. and Tech. 2021; 14(12): 6558-6564.

Received on 24.02.2025 Revised on 02.04.2025

Accepted on 05.05.2025 Published on 10.07.2025

Available online from July 17, 2025

Asian J. Pharm. Res. 2025; 15(3):234-240.

DOI: 10.52711/2231-5691.2025.00038

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Creative Commons License.