Formulation and Evaluation of Lomefloxacin Microspheres

 

Swati S Talokar*, Rohan R Vakhariya

Rajarambapu College of Pharmacy Kasegaon. Dist –Sangli Tal –Walwa Maharashtra

 

 

ABSTRACT:

Microspheres are powders consisting of proteins or synthetic polymers. Microsphere is one approach of delivering active drug ingredient to targeted site.  They can overcome the problems of conventional therapy and enhance the therapeutic efficacy of a given drug. Microspheres received much attention for prolonged release as well as for targeting anticancer drugs to the tumor. The present study describes formulation of Lomefloxacin microspheres. In future by combining various other strategies, microspheres will find the central place in novel drug delivery. Formulated microsphere is evaluated for its surface morphology, particle size, in vitro drug release, drug entrapment efficiency. All the results were up to the mark and were found satisfactory.

 

 

 

1. INTRODUCTION:

Gastro retentive dosage form remains in gastric region for longer period of time and hence prolongs the residence time of drug. Prolong gastric retention improves bioavailability; reduce drug waste and increases solubility of drug in high pH. It is also suitable for local delivery stomach and proximal intestine.[1] Microspheres are one such approach for gastro retentive dosage form. Microspheres are spherical particles, ranging from 1μm to 1000μm. These are also referred as micro particles. There are ranges of techniques for the preparation of microspheres. These offer a variety of opportunities to control aspects of drug administration. Microspheres facilitates the accurate delivery of small quantity of the potent drugs, reduced drug concentration at the site other than the target site and the protection of the labile compound. To obtain maximum therapeutic efficacy, it becomes necessary to deliver the agent to the target tissue in the optimal amount.[2]

 

Formulation of Microspheres:

Preparation of microspheres should satisfy following criteria:

1.      They should have ability to incorporate reasonably high concentrations of the drug.

2.      Microspheres should remain stable after synthesis with a clinically acceptable shelf life.

3.      Microsphere should have controlled particle size and should show dispersability in aqueous vehicles.

4.      Release of active reagent with a good control over a wide time scale.

5.      Biocompatibility with a controllable biodegradability

6.      Susceptibility to chemical modification.

 

Lomefloxacin is member of the fluoroquinolone class of antimicrobial drugs. It is active against a wide range of gram positive as well as gram negative organisms. Lomefloxacin is known to exert their antibacterial action by antagonism of the enzyme DNA gyrase, also known as bacterial topoisomerase II. Lomefloxacin acts on this enzyme and cause inhibition of DNA synthesis, antagonism of RNA and protein synthesis and ultimately cell death.[3] In present study Lomefloxacin has been selected for formulation of gastric floating drug delivery system .

2. MATERIAL AND METHOD:

2.1 MATERIAL:

Lomefloxacin was Cipla Research Center, Mumbai, India. HPMC K4M and ethylcellulose were purchased by Research Lab Mumbai. All chemicals used were of analytical grade. The other inactive ingredients viz. dichloromethane and tween 20 was procured from Research Lab Mumbai.

 

3 PREFORMULATION STUDIES:

3.1 Solubility:

Solubility of Lomefloxacin was determined in ethanol, acetone and water.

 

3.2 Melting Point Determination:

Melting point of Lomefloxacin was determined by open capillary method.

 

3.3 Determination of Maximum Wavelength:

A Solution of Lomefloxacin containing the concentration 10ug/ml was prepared in 0.1M HCl and UV spectrum was taken using Shimadzu (UV-1360) double beam spectrophotometer. The solution was scanned in range of 200-600nm.

 

4. FORMULATION STUDIES:

Following is the formulation table. Number of four batches was prepared with varied concentration of Hydroxy Propyl methyl cellulose and ethyl cellulose.

 

Table no.1. Formulation table with different batches.

Ingredients	Formulation code
	LM1	LM2	LM3	LM4
Drug (Lomefloxacin)(mg)	400	400	400	400
Hydroxy Propyl Methyl Cellulose K15M(mg)	100	150	200	250
Ethyl cellulose(gm)	0.5	1	1.5	2
Dichloromethane(ml)	10	10	10	10
Ethanol(ml)	10	10	10	10
Tween 80	0.1ml	0.1	0.1	0.1
Distilled water	100ml

 

 

4.1 METHOD[4]:

Floating microspheres with were prepared by using a modified emulsion diffusion technique. Weighed quantities of Lomefloxacin, Ethyl cellulose, and hydroxy propylmethyl cellulose(HPMC K15M) were dissolved in a mixture of ethanol and dichloromethane (10:10 solvent ratio) at room temperature in a magnetic stirrer at 500 rpm for 15 min. This solvent was poured drop wise into 100 mL distilled water containing 0.1mL of Tween 80 maintained at a temperature of 50± 2 °C. The resultant solution was stirred at 500 rpm for 15 min to allow the volatile solvent to evaporate. This resulted in the formation of microspheres. Different ratios of polymers were used to prepare the microspheres

 

5 EVALUATIONS OF MICROSPHERES:

5.1 Calibration curve of Lomefloxacin [4]

From the Lomefloxacin standard stock solution (1000ug/ml), 1ml solution was diluted to 10 ml using 0.1 M HCL solution to get concentration of 100ug/ml. From this solution, aliquots of 1ml, 2ml, 3ml, 4ml, 5ml from standard drug solution were diluted to 10ml with 0.1M HCl .The absorbance of this solution was measured at 268 nm.

 

5.2 Procedure for in-vitro dissolution studies:

The release rate of lomefloxin floating microsphere was determined by rotating basket method. The dissolution test was performed using 900 ml 0.1 M HCl at 50 rpm. Lomefloxacin floating microspheres equivalent to 80 mg were placed in basket to avoid floating of microspheres. A sample (5ml) of the solution was withdrawn from the dissolution apparatus hourly and the samples were replaced with fresh dissolution medium. The sample was passed through Whatman filter paper and the absorbance of this solution was measured at 268 nm. Dissolution profile of the formulation was analyzed by plotting drug release versus time plot.

 

5.3 FTIR Studies:

FTIR spectroscopy on fourier transformed infrared spectrophotometer .The pellet of drug  and potassium bromide were prepared by compressing the powder at 20 psi for 10 min on KBr press and the spectra were scanned in the wave number range of 4000-600 /cm. FTIR studies was carried on lomefloxacin  loaded microsphere and lomefloxacin drug.

 

5.4 Surface morphology SEM:

Scanning electron microscopy has been used to determine particle size distributon, surface topography, texture and to examine the morphology of fractured or section surface.SEM is probably the most commonly used method for characterizing drug delivery system, owing  to simplicity of sample preparation.SEM studies were carried out by using JEOL JSM T-330A scanning microscope Japan.

 

5.5 Drug Entrapment Efficiency:

Beads equivalent to 100 mg of the drug were taken for evaluation. The amount of drug entrapped was estimated by crushing the beads and extracting with aliquots of 0.1N HCl. The extract was transferred to a 100 ml volumetric flask and the volume was made up using 0.1N HCl. The solution was filtered and the absorbance was measured at 279 nm against appropriate blank. The amount of drug entrapped in the beads was calculated by the following formula

Amount of drug actually present
Drug entrapment efficiency=	-------------------------	x100
Theoretical drug loaded expected

5.6 Frequency distribution analysis:

Determination of average particle size of Lomefloxacin floating microsphere was carried out by optical microscopy in which stage micrometer was employed .A minute quantity of Lomefloxacin floating microsphere was spread on a clean glass .Lomefloxacin floating microsphere was determined in each batch. In order to be able to define a frequency distribution or compare the characteristic of particle with many different diameters, the frequency distributions are broken down into different ranges and is presented in a form of a histogram.

 

5.7 Percentage yield:

Percentage practical yield of lomefloxacin floating microsphere is calculated to as certain efficiency method of production. As per the equation

 

	Wt. of microsphere
Percentage yield=	--------------------------------	x100
	Wt. of solid excipient

 

6 RESULTS AND DISCUSSION:

6.1 Pre formulation Studies

6.1.1 Solubility study

Lomefloxacin was found to be freely soluble in ethanol, acetone, sparingly soluble in water

 

 

6.1.2Melting point determination

The melting point of Lomefloxacin was found to be 150⁰ C

 

6.1.3. Calibration Curve of Lomefloxacin

 

Fig. no 1 Calibration curve of Lomefloxacin drug

 

6.1.4 Determination of lambda max.of Lomefloxacin:

Maximum wavelength of Lomefloxacin was found at 280 nm

 

7. Evaluation test of optimized batch F4:

7.1 Drug Polymer interaction (FTIR) study:

The drug excipient compatibility studies reveal that there were no physical changes observed in drug and polymer mixtures. The spectral observations indicated that the principal IR absorption peaks observed in the spectra of drug were close to those in the spectra of the microspheres containing drug. IR spectrums of the microspheres indicate that there is no strong interaction between the drug and the polymers (Fig.3)

 

Fig.no 2.  I.R spectra of Lomefloxacin drug

 

Fig.no 3   I.R spectra of Lomefloxacin microsphere

 

 

7.3 Surface morphology of Lomefloxacin microsphere:

The SEM of microspheres shows a spherical structure with a smooth surface morphology  .The outer surface of the microspheres was smooth and dense, while the internal surface was porous.

 

Fig.no 4 SEM of Lomefloxacin microsphere.

 

7.4 Frequency distribution analysis:

As drug to polymer ratio was increased the mean particle size of microsphere was also increased.

 

Table no 2. Particle size range

Size range(um)	No. of particles
0-30	30
30-60	55
60-90	75
90-120	35

 

Fig.no 5 Histogram of particle size distribution.

 

7.5 In vitro dissolution

Table no.3 In-vitro drug release of formulated batches

Sr. no	Time (hr)	Cumulative drug release
		LM1	LM2	LM3	LM4
1	0.5	12.02	14.199	11.37	15.68
2	1	25.56	23.11	28.2	26.48
3	2	32.40	38.19	35.63	35.40
4	3	46.0.8	46.50	44.88	42
5	4	52.6	53.33	49.11	49.6
6	5	56.45	56.14	52.56	55
7	6	63.88	60.45	60.255	64.31
8	7	75.67	64.51	69.76	73.42
9	8	86.79	72.33	77.51	88.76
10	9	90.45	80.17	87.23	94.24
11	10	92.50	88.60	93.22	96.8

 

7.6 Percentage yield and percent entrapment efficiency of batches are:

Table no.4 Percentage yield and entrapment efficiency of formulated batches

Sr. no	Formulation code	Percentage yield	Entrapment efficiency
1	LM1	84.96 %	79.96
2	LM2	85.38%	83.87
3	LM3	85.26%	79.63
4	LM4	86.955%	89.60

 

8. CONCLUSION:

From the results it can be concluded that polymers like ethyl cellulose, HPMC can be used to formulate floating microspheres. Particle size analysis revealed that particles were of appropriate size and texture. In-vitro drug release studies showed release from microsphere upto 11 hours.LM4 batch was optimized which showed proper entrapment efficiency, percentage yield, drug release. Hence microspheres are proved to be better choice of drug delivery than many other types of drug delivery system.

 

9. REFERENCE:

1.       Patil J.M, Herlekar R.S Gide P.S. Kadam V.J .Trends in Floating Drug Delivery System. Journal of Scientific and Industrial Research 65 2011 p11-21

2.       Kataria Sahil, Middha Akanksha, Sandhu Premjeet. Microsphere: A Review International Journal Of Research In Pharmacy And Chemistry ;1(4) 2011 P-1184

3.       Abdul Malik P.H, S Satyanandam. PH-induced In Situ Gelling System of Lomefloxacin for Sustained Ocular Deliver. International Journal of Pharmaceutical Sciences and Drug Research; 7(5) 2015 p- 401

4.       Mona Semalthy, Shikha Yadav. Preparation and Characterization of Gastroretentive Floating Microsphere of Ofloxacin Hydrochloride. International Journal of Pharmaceutical Science and Nanotechnology;3(1) 2010

5.       Swatantra Bahadur Singh, Shweta Singh. Validated UV-Spectrophotometric method for quantitative estimation of Lomefloxacin HCl in bulk and pharmaceutical dosages forms. World Journal of Pharmaceutical Sciences 2014; 2(11): 1520-152

 

 

 

 

Received on 04.01.2017       Modified on 28.01.2017

Accepted on 15.02.2017     ©A&V Publications All right reserved