RESEARCH ARTICLE

Formulation and Evaluation of Gastroretentive Floating Beads of Cefuroxime Axetil

Chandrashekar Patil*, Kousarbanu Indikar, Bhaskar Umarji

Department of Pharmaceutics, B.L.D.E.A’s College of Pharmacy, BLDE University Campus, Bijapur-586 103

*Corresponding Author E-mail: drccpatil@gmail.com

ABSTRACT:

Cefuroxime axetil is a second generation antibacterial agent belongs to cephalosporin group. It undergoes rapid metabolism in the intestinal mucosa due to change in pH environment and hence decreased oral bioavailability. A gastro retentive floating beads of cefuroxime axetil were formulated to increase the bioavailability. The floating beads were prepared by Ionotropic gelation method in which drug and calcium carbonate were dispersed in four different concentrations into a polymer mixture of three different combinations such as sodium alginate along with guar gum, sodium alginate with HPMC K4M, and sodium alginate with hydroxy ethyl cellulose solution and then dropping the dispersion into an acidified solution of 3% (w/v) calcium chloride. The prepared beads were evaluated for bead size, entrapment efficiency, in-vitro drug release, swelling study, buoyancy test, SEM, X-ray diffraction, FTIR and in vivo gastric retention time in albino rats. The drug entrapment efficiency was found to be in the range of 54.76 to 81.87 %. The in-vitro drug release was observed up to 8 hr. The drug release followed Fickian transport. In vivo studies indicated that a significant increase in gastric residence time of beads.

KEYWORDS: Cefuroxime axetil, Gastroretentive Floating microbeads, Sodium alginate, Guar gum, HPMC, HEC, Ionotropic gelation.

INTRODUCTION:

Oral route is the most convenient and extensively used route for drug administration. This route has high patient acceptability, primarily due to easy administration. Oral route of administration has been received more attention in the pharmaceutical field because of the more flexibility in the designing of dosage form than drug delivery design for other routes.^[1] Drugs that are easily absorbed from the GIT (Gastro Intestinal Tract) and eliminated quickly from the blood circulation. To avoid this problem the oral controlled release formulation has been developed, as these will release the drug constant drug concentration in the serum for a longer period of time.^[2] Various approaches have been worked out to improve absorption of an oral dosage form in stomach. High density systems whose action on their dipping to the bottom of the stomach. Systems attaching to the mucus membrane are bioadhesive systems are retained in the stomach due to their ability to stick to and stay on the surface of the mucus membrane of the stomach. Intragastric floating systems are based on the phenomenon of drug floating in the gastric contents.

Received on 03.09.2014 Modified on 12.09.2014

Research J. Pharm. and Tech. 8(1): Jan. 2015; Page 13-19

DOI: 10.5958/0974-360X.2015.00003.7

There are three possible techniques to rendered drug floating. Gas contain floating systems: generation of CO₂via chemical reaction between sodium bicarbonate and hydrochloric acid of gastric juice. The gas kept in the stomach ensures its floatation. Thus prolongs the period of drug occurring in the stomach. Systems with low density core not subject to rapid chemical and physical changes, providing for the drug floatation. The core is coated with a gel or other polymer shells from which drug are gradually released.^{[3, 4]}

Cefuroxime axetil is a second generation antibacterial agent belongs to cephalosporin group. Cefuroxime axetil is absorbed from gastrointestinal tract and is rapidly hydrolysed in the intestinal mucosa to cefuroxime which is an unobservable form. Hence gastroretentive floating beads of cefuroxime axetil were formulated to increase the drug bioavailability.^[5]The objective of present investigation is to prepare a sustained release floating beads of cefuroxime axetil using polymers of different permeability. Anionic sodium alginate, as primary polymer with oppositely charged counter ion polymer namely guar gum, hydroxy propyl methyl cellulose and ethyl cellulose together with gas forming agent CaCO₃in separate batches. The effects of CO₂ gas formation on the physical properties, morphology, floating ability, drug loading, drug entrapment and release rate of alginate beads were examined. The comparative efficacy of CaCO₃ as gas forming agent and polymer for FDDS was also evaluated.

MATERIALS AND METHODS:

Cefuroxime axetil was a gift sample from Cipla Ltd Baddi, Himachal Pradesh, India. Sodium alginate was purchased from S.D fine chemicals, Mumbai. Guar gum was purchased from Punit chemicals, Mumbai. HPMC K4M was a gift sample from Kemwell biopharm, Bengalore. Hydroxy ethyl cellulose was purchased from Loba chemie, Mumbai. All other chemicals used were of analytical grade.

The drug cefuroxime axetil was dispersed in 30 ml alginate solution (2 % w/v) containing guar gum (alginate:guar gum=9:1 w/w). Then gas forming agent such as CaCO₃ was added to the above solution in different concentration 0.4, 0.6, 0.8, and 1(gas‐forming agent/alginate, w/w). Similarly, other formulations with the same method except the change which is the guar gum is replaced with1% w/v HPMC K4M and 1% w/v hydroxyl ethyl cellulose (HEC)‐ The formulation compositions are shown in Table 1.

The resulting solution was dropped through a 23G syringe needle into 3% (w/v) CaCl₂ solution containing 2% (v/v) acetic acid. The solution containing suspend beads was stirred with a magnetic stirrer for 2 hrs to improve the mechanical strength of the beads and allowed to complete the reaction to produce gas. Since the carbonate salts are insoluble at neutral pH, the divalent ions were only released in the presence of acid, thereby preventing premature gelation. The fully formed beads were collected, washed with ethanol and distilled water. The floating beads were shown in Fig 1.

Fig- 1.Floating beads

Estimation of Drug Entrapment Efficiency:

Known amount of microbeads (100 mg) were added to 100 ml buffer of pH 7.4 for complete swelling at 37 ^oC. The microbeads were crushed in a glass mortar with pestle; the solution was then heated gently for 2 hrs to extract the drug completely and then filtered. The clear supernatant solution was analyzed for drug content using UV-visible spectrophotometer at 281 nm.^[7] DEE was determined using a formula

Actual drug content

DEE= ---------------------------- x 100

Theoretical drug content

In-Vitro Drug Release Study:

In-vitro drug release study was carried out using a USP-23 dissolution tester. The dissolution was measured at 37.0 ± 0.5 ^oC and 50 rpm basket speed. Drug release from the microbeads was studied in 900 ml acidic medium (pH 1.2) for 8 hrs. At predetermined time intervals, 5 ml aliquots were withdrawn and replaced with the same volume of fresh solution. The amount of drug released was analyzed using UV-visible spectrophotometer at a l_max of 281 nm.^[8]

Swelling Study:

The 50 mg of beads were incubated with 25 ml buffer solution of pH 1.2 at 37 ^oC. The beads were taken out at different time intervals and blotted carefully without pressing hard to remove the excess surface liquid. The swollen beads were weighed using the electronic microbalance. The percent water uptake (Q) at different time intervals was calculated using the following Eq.^[9]

Q= W_t / W_o

Where W₀is mass of the dry beads and W_tis the mass of swollen beads.

Table 1: The formulae for the preparation of cefuroxime axetil beads

Formulation codes	S.A (% w/w)	S.A:Guar gum (% w/w)	S.A:HPMC K4M (% w/w)	S.A: HEC (% w/w)	S.A:Cefuroxime axetil (%w/w of polymer)	S.A:Calcium carbonate (%w/w)	Calcium chloride (%w/v)	Glacial acetic acid (%w/v)
F1	9	1	--	--	20	1:0.4	3	2
F2	9	1	--	--	20	1:0.6	3	2
F3	9	1	--	--	20	1:0.8	3	2
F4	9	1	--	--	20	1:1	3	2
F5	9	--	1	--	20	1:0.4	3	2
F6	9	--	1	--	20	1:0.6	3	2
F7	9	--	1	--	20	1:0.8	3	2
F8	9	--	1	--	20	1:1	3	2
F9	9	--	--	1	20	1:0.4	3	2
F10	9	--	--	1	20	1:0.6	3	2
F11	9	--	--	1	20	1:0.8	3	2
F12	9	--	--	1	20	1:1	3	2

S.A- Sodium Alginate, HPMC K4M- Hydroxy propyl methyl cellulose, HEC- Hydroxy ethyl cellulose.

Buoyancy of Beads:

Floating properties of dry alginate beads were evaluated using USP dissolution apparatus containing 900 ml acidic buffer (Ph 1.2) at rotational speed of 75 rpm. The temperature of medium was maintained at 37 ± 20 ⁰C. Fifty beads were placed in the media and the total floating time was measured by visual observation^[10]

Scanning Electron Microscopic Studies:

The beads were mounted onto stubs using double sided adhesive tape and sputter coated with platinum using a sputter coater (Edward S 150, UK). The coated beads were observed under SEM (JEOL, JSM-6360, Kyoto, Japan) at the required magnification at room temperature. ^[11]

Differential Scanning Calorimetric Analysis:

The samples were heated from 0-300 ^oC at a heating rate of 10^oC/min under argon atmosphere using a microcalorimeter (DSC Q20 V24.4 Build 116, TA Instruments, USA) and then thermograms were obtained.^[12]

X-Ray Diffraction Studies (X-RD):

The spectra were recorded using a Philips, PW-171, x-ray diffractometer with Cu-NF filtered CuKa radiation. Quartz was used as an internal standard for calibration. The powder x-ray diffractometer was attached to a digital graphical assembly and computer with Cu-NF 25 KV/20 mA tube as a CuKa radiation source in the 2q range 0-50^o.^[13]

Fourier Transform Infrared Spectroscopy:

The samples were crushed with KBr to make pellets under hydraulic pressure of 600 kg, and then the FTIR spectra were recorded between 400 and 4000 cm^-1[14]

In Vivo Study in Albino Rats:

Gastric residence efficacy of beads was evaluated by the method of Zheng et al. with slight modification. Albino rats divided into three groups of two animals fasted for 24hrs before the experiments but were allowed free access to water and then divided into three groups of two animals. Twenty beads from the optimized batch were orally administered with 5 ml of water to rats. The rats were dissected after 2, 4, and 8 hrs. The stomach of the rats were removed and opened along the great curvature, the beads that remained in the stomach were counted. This animal study was permitted by Institutional Ethics Committee (IAEC).^{[15, 16, 17]}

RESULTS AND DISCUSSION:

The cefuroxime axetil loaded floating beads of sodium alginate, guar gum, HPMC K4M and HEC were prepared by Ionotropic gelation method using calcium carbonate as a gas generating agent and calcium chloride as a cross linking agent. The average beads size was found to be in the range of 2511 to 3923 mm as shown in Table 2.

Table-2. Average bead size and drug entrapment efficiency (DEE) of gastroretentive floating beads

SR.NO	Beads	Average size (µm)	DEE (%)
1	F1	2511±4.58	81.87±0.92
2	F2	3285±2.6	72.78±0.17
3	F3	3349±1.52	66.53±0.56
4	F4	3702±2.61	66.27±0.29
5	F5	2629±3.51	58.18±0.19
6	F6	2887±4.50	57.62±1.58
7	F7	3501±4.35	57.31±1.10
8	F8	3923±2.51	54.76±0.45
9	F9	3074±1.52	64.71±0.52
10	F10	3465±3.60	64.22±0.79
11	F11	3499±3.78	60.27±0.53
12	F12	3912±2.0	57.67±0.17

By increasing the proportion of gas forming agent, the size of the beads were increased and spherical beads could not be formed because released CO₂gas burst the bead before the wall was sufficiently hardened. The drug entrapment efficiency was found to be in the range of 54.76 to 81.87 % as shown in Table 1. It was observed that an increase in the proportion of CaCO₃ resulted in a decrease in the entrapment efficiency of drug in floating beads. During the preparation of beads, CaCO₃ react with acetic acid to release CO₂, which permeates the alginate matrix, leaving pores. These porous beads, with a less dense internal structure, results in decreased entrapment efficiency. The in-vitro drug release study was performed using dissolution rate test apparatus in 0.1 N HCl (pH 1.2). The dissolution profiles are given in Figure 2-4.

Fig 2.In vitro drug release profile of floating beads from F1-F4

Fig 3.In vitro drug release profile of floating microbeads from F5-F8

Cefuroxime axetil has shown characteristic intense peaks between the 2q of 10^o and 20^o due to its crystalline nature. Whereas, in case of F3, F7 and F11, no intense peaks related to drug were noticed between the 2q of 10^o and 20^o. This indicates the amorphous dispersion of the drug after entrapment into microbeads. The drug-polymers interaction was studied by FTIR analysis and is presented in Figure 9.

Figure 9: FTIR spectra of cefuroxime axetil (A), and F3 beads (B).

The spectra of cefuroxime axetil showed the characteristic peaks at 3479 cm^-1 due to stretching vibration of OH groups, peaks at 3011 cm^‑1, 2943 cm^‑1 and 2824 cm^‑1stretch are due to CH stretching vibrations, and peak at 2363 cm^‑1 stretch is assigned to carboxylic acid, 1676 cm^‑1 stretch for carbonyl group, 1538 cm^‑1 amines and 755 cm^‑1 for Sulphur group. Whereas in the spectra of formulation F3, the same characteristics peaks related to drug were noticed with slight variations. This ruled out the drug-polymers interaction, hence, the drug is stable in the formulations. The release data were fitted according to first order release, Higuchi’s equation and the mechanism of drug release was calculated according to Korsemeyer’s Peppas equation. The calculated “n” values along with the correlation coefficients have been shown in Table 3.

Table 3: kinetic values of cefuroxime axetil release from beads

Microbeads	First order	Higuchi Equation	Korsemeyer’s Equation
Microbeads	R	R	n	R
F1	0.748	0.748	0.381	0.878
F2	0.656	0.656	0.43	0.958
F3	0.857	0.857	0.437	0.935
F4	0.748	0.748	0.286	0.831
F5	0.859	0.859	0.244	0.972
F6	0.957	0.957	0.408	0.963
F7	0.881	0.881	0.329	0.966
F8	0.921	0.921	0.348	0.958
F9	0.9	0.9	0.319	0.967
F10	0.915	0.915	0.319	0.979
F11	0.933	0.933	0.344	0.987
F12	0.872	0.872	0.319	0.946

The drug released through diffusion and the values of n depend upon the polymer concentration. The calculated “n” values suggest that the mechanism of drug release followed Fickian transport. The in vivo gastric retention time of prepared cefuroxime axetil microbeads have been evaluated by counting the number of microbeads in rat stomach after dissection. It was observed that the number of microbeads administered were almost equal to the number of microbeads obtained from the rats stomach as shown in the Figure.10. Hence the beads were remainined in stomach for up to 8 hrs.

Figure 10. Floating beads in rat stomach after 2hrs (A), 4hrs (B) and 8hrs (C).

ACKNOWLEDGEMENTS:

The authors are thankful to Cipla lab. Ltd. Baddi (H.P) for providing gift sample of Cefuroxime axetil. The authors express their deep gratitude towards Principal Dr.Navanath V. Kalyane, B.L.D.E.A’s College of Pharmacy, Bijapur for providing facilities and encouragement in the successful completion of this work.

REFERENCES:

1. Kamla p, Shashi kiran m. Formulation and evaluation of oil entrapped gastroretentive floating gel beads of loratadine. Acta Pharm. 2008;58:187–197.

2. Chein YW. Novel Drug Delivery System. Oral drug delivery. Drug and Pharmaceutical Sciences, 2nd Edition, Marcel Dekker, New York, 2005;139-41.

3. Samyuktha Rani B, Vedha Hari B.N, Brahma RA, Punitha S, Parimala Devi, Rajamanickam V. The recent development on gastric floating drug delivery systems:An overview. Int J Pharm. Tech. 2010;2(1):524-534.

4. Shruti S, Ashish P, Shikha A, Raju C. A Review On: Recent Advancement of Stomach Specific Floating Drug Delivery System. Int J Pharm. Bio Arc. 2011;2(6):1561-1568.

5. William AP, Pencillins Cephalosporins and other β lactam antibiotics. In: Bruntan LL, Lazo JS,Parker KL, editors. Goodman and Gilman’s: The Pharmacologic Basis of Therapeutics. 11^th ed, New York: McGraw-Hill. 2006;128-48.

6. Girish K. Tripahi, Singh S, Nath G. Formulation and evaluation of pH sensitive polymeric blended microgel beads of clarithromycine for the effective treatment of Helicobacter pylori. Der Pharmacia Sinica, , 2010;1(3):245-255.

7. Patil S. M, Patil S.M, Goudanavar P. S, Bagali R.S, chandrashekhara.S and Patil S. Design and characterization of diclofenac sodium microbeds by Ionotropic gelation technique. Int J Pharm.Bio Sci. 2010;(2):1-10.

8. B. AppaRao, Shivalingam M.R, Kishore Reddy Y.V, Sunitha N, Jyothibasu T, Shyam T. Design and evaluation of sustained release microcapsules containing diclofenac sodium. Int J Pharm. Biomed. 2010;1(3):90-93

9. Rashmi B, Raghavendra V.K, Chitrali Mallikarjun Setty and Navanath V. Kalyane. “Carboxymethylcellulose ̶ aluminum hydrogel microbeads for prolonged release of simvastatin”. Acta. Pharm. Sci. 2010;52:137-143.

10. Santhosh Kumar M, Chowdary K.A And Sammaiah G. Controlled Release Formulation And Evaluation Of Aceclofenac By Microencapsulation. An Int J of Adv Pharm. Sci. 2011;2(3):133-145.

11. B.Pradeep, M.Nagamadhu, David Banji, B. Bindu Madhavi, G. Arjun, K.Shekhar. Formulation and evaluation of valacyclovir hydrochloride microcapsules. Int J Pharm. Pharm. Sci. 2011;3(2)92-96.

12. Santhosh Kumar M, Chowdary K.A And Sammaiah G. Controlled Release Formulation And Evaluation Of Aceclofenac By Microencapsulation. An Int J of Adv Pharm. Sci. 2011;2(3):133-145.

13. manjanna k.m, shivakumar.b, pramod kumar t.m. formulation of oral sustained release aceclofenac sodium microbeads. int j pharm. tech res. 2009;1(3):940-952.

14. Shekhar. K, naga madhu. M,.bindu madhavi. M, arjun .G, pradeep .B, david banji. Formulation and evaluation of cefotaxime sodium microcapsules. Int J Pharm. Res and Dev. 2011;2(10):80-86. .

15. Zhen-Hai Zhang, Yong-Shun Sun, Hui Pang , Were L.L. Munyendo , Hui-Xia Lv and Sheng-Liang. Preparation and Evaluation of Berberine Alginate Beads for Stomach-Specific Delivery. Molecules . 2011;16:10356-10347

16. Mrunalini Narkar, Praveen Sher, and Atmaram P. Stomach-Specific Controlled Release Gellan Beads of Acid-Soluble Drug Prepared by Ionotropic Gelation Method. American Ass Pharm. Scientists 2010;267-277.

17. Rishi Pal , Anil P. S. Bhadoria and Suman R. Preparation and characterization of sodium alginate-carbopol-934P based mucoadhesive microbeads. Sch Res Lib. 2011;3(5):1-11.