\Ofloxacin Loaded Lipid colloidal carrier (Liposphere) for Treatment of Bacterial Infections

 

Satheesh babu N.1*, Prabakaran L.1 and Gowthamarajan K.2

1Dept of Pharmaceutics, Karpagam College of Pharmacy, Coimbatore, India-641032.

2Dept of Pharmaceutics, JSS College of Pharmacy, Ooty, India.

*Corresponding Author E-mail: satheeshbabu_mpharm@yahoo.co.in

 

ABSTRACT:

Aim of the present research was to investigate the influence of formulation parameters on production of ofloxacin loaded lipid colloidal carriers (lipospheres). Lipospheres of ofloxacin were formulated by melt dispersion technique using cetyl alcohol in different drug–lipid ratios. PVA (surfactant) and pectin (co-surfactant and stabilizer) were used. Mean particle size, percentage encapsulation efficiency and drug release at end of 8hr were considered. The optimized formulation containing the lipophilic drug displayed satisfactory encapsulation efficiency 73% and a mean diameter of 62 μm. The formulated lipospheres were characterized by morphological characters such as Photomicroscope, Scanning electron microscope, entrapment efficiency, percentage of yield. In-vitro drug release, which showing that all the formulations were released the drug in controlled manner.

 

KEYWORDS: Lipospheres, Cetyl alcohol, Ofloxacin, encapsulation efficiency, In Vitro Release.

 

 


INTRODUCTION:

Lipospheres are a new type of lipid (triglyceride) based encapsulation technique developed for both hydrophobic drugs and hydrophilic drugs1. Lipospheres are, particulate dispersion of solid spherical particles of a particle size between 0.2-100 μm in diameter consisting of solid hydrophobic lipid core such as triglycerides or fatty acid derivatives, stabilized by a monolayer of phospholipids1. Internal core comprises the drug dispersed or dissolved in solid lipid matrix. The lipospheres colloidal  carrier system has gained several advantages than other  carrier drug delivery systems in terms of physical stability, low cost of excipients, ease of production and scale-up, high dispersability in an aqueous vehicle, high entrapment of lipophilic drugs, controlled particle size and sustained release of entrapped drug 2.

 

Structure of Liposphere

 

The fluoroquinolone antibiotic ofloxacin is proposed use for the treatment of different diseases such as, respiratory tract infection, skin structure, bone and gastrointestinal infections, urinary tract infections 3-7, gonorrhea. Ofloxacin has broad activity against bacterial (Helicobacter pylori) infections and is used in combination with other drugs to treat tuberculosis. However, many studies were developed to enhance the potency and spectrum, to achieve sustained blood levels, and to minimize drug interactions with various metabolic pathways and physiological processes. Especially, the use of antibiotic

“carrier delivery systems” would result in enhanced concentrations of the antimicrobial agent at the infected area.

 

Normal dosage regimen varies from 200-600 mg administered bid or t.i.d, depending on severity of infection. In severe cases, long-term therapy may also be needed. Biological half-life of drug is from 5-6 hrs. As it requires frequent dosing to maintain the therapeutic effect, hepatotoxicity has also been reported with the use of ofloxacin8 . To reduce the above mentioned adverse effects, ofloxacin is encapsulated in lipid carrier system there by it  required to reduce the frequency of dosing, thereby improving the patient compliance  targeting the micro organism via lymphatic circulation instead of systemic circulation, thereby reduce the hepatic metabolism and increasing the therapeutic efficacy. Thus, it was chosen as a model drug for the present study.

 

Present investigation was taken up in order to develop formulation of lipospheres containing ofloxacin followed by its characterization by various techniques particle size and size distribution, encapsulation efficiency, in-vitro drug release.

 

MATERIALS AND METHODS:

Materials:

Ofloxacin procured from Micro Labs Ltd, Bangalore, India. Cetyl alcohol, Pectin was purchased from Loba Chemie Pvt Ltd, Mumbai. All other chemicals used were of analytical grade.

 

Methods:

a. Preparation of Lipospheres:9

Lipospheres were prepared by a method based on the melt dispersion technique. The formulation of different batches is depicted in Table 1. Briefly, cetyl alcohol was melted on a water bath maintained at 70-72°C.  Finely powdered drug was dispersed in the molten wax. Aqueous phase was prepared by heating a blend of water and poly vinyl alcohol (Surfactant) to 70-72°C. Pectin (co-surfactant) was added to the aqueous phase. The oily  phase was added to the aqueous phase and emulsification was assisted by stirring the content on a mechanical stirrer. The milky formulation was then rapidly cooled to about 20°C by immersing the formulation flask in a cool water bath without stopping the agitation to yield a uniform dispersion of Lipospheres. The obtained Lipospheres were then washed with water and isolated by filtration through a paper filter.

 

Table 1: Formulation Variables in Ofloxacin Lipospheres

Batch No.

Cetyl alcohol

(mg)

PVA

(mg)

Ofloxacin

(mg)

Pectin

(mg)

F 1

250mg

25mg

100mg

5mg

F 2

500mg

25mg

100mg

5mg

F 3

250mg

50mg

100mg

5mg

F 4

500mg

50mg

100mg

5mg

F 5

750mg

50mg

100mg

5mg

 

b. Evaluation of Lipospheres:

i. Determination of Particle Size:

The particle size analysis of ofloxacin loaded lipospheres was carried out by optical microscopic method. The average particle sizes are depicted in Table 2.

 

ii. Photomicroscopical Evaluation:

The   lipospheres were evaluated for surface and physical characteristics by photomicroscope (Nikon) at 40 x (40 x 10 magnification).

 

iii. Scanning Electron Microscopical Evaluation:

The surface morphology and shape of the lipospheres were analyzed by scanning electron microscopy for selected batches (Leo, VP-435, Cambridge, UK).

 

iv. Determination of Encapsulation efficiency:

The amount of drug entrapped in the lipospheres of various batches of products was analyzed by the following method. Hot phosphate buffer was added to the finely powdered lipospheres (100mg) and the resultant solutions were analysed spectrophotometrically at 294 nm using phosphate buffer solution (pH-7.4) as blank. The results of the analysis are depicted in the Table 2.

 

Table 2: Particle Size Analysis of Ofloxacin Lipospheres

Batch No.

Average Particle Size

(Micron)

Encapsulation Efficiency (%)

F 1

49.2µm

42%

F 2

60.0µm

55%

F 3

66.9µm

61%

F 4

62.5µm

73%

F 5

71.5µm

75%

 

v. In vitro release studies:

In vitro release of ofloxacin from lipospheres was evaluated in phosphate buffer (pH-7.4). Amount of lipospheres equivalent to 100mg of ofloxacin were transferred to the prewarmed dissolution media (900ml) and maintained at 37±0.5°C under stirring at 50rpm. Samples were withdrawn at different time intervals up to 8 hrs and the volume was replaced immediately by fresh phosphate buffer. The sample withdrawn was centrifuged (3000rpm, 15min). The supernatant solution was filtered and analyzed for ofloxacin content by measuring absorbance in UV-spectrophotometer (Cyber lab USA) at 294nm by using phosphate buffer (pH-7.4) as blank. And the cumulative percentage (%) of drug released was calculated (6) and depicted in the Table 3.

 

Table 3: Dissolution Profile of ofloxacin Lipospheres

Sl. No

Time

(Hrs)

Cumulative % of Drug released from various formulation

F1

F2

F3

F4

F5

1

0

0.000

0.000

0.000

0.000

0.000

2

0.25

4.121

5.001

5.772

4.102

5.472

3

0.5

8.580

9.856

8.478

7.924

8.006

4

1

18.022

23.721

21.532

20.758

22.846

5

2

22.109

31.578

30.156

27.379

29.684

6

4

47.346

48.097

43.094

39.487

41.348

7

6

61.673

56.994

57.007

46.727

48.781

8

8

83.217

73.864

64.781

52.684

58.764

 

3. RESULT AND DISCUSSION:

Lipospheres prepared by melt dispersion technique were found be discrete and through photomicroscope, SEM analysis their size was found to be 49.2, 60, 66.9, 62.5 and 71.5 µm of formulations F1 to F5 respectively. The encapsulation efficiency of lipospheres was found to be 42%, 55%, 61%, 73%, and 75% of formulations F1 to F5 respectively. The formulation F4 showed highest entrapment efficiency of 73% as well as particle size of 55.4 µm. Cumulative percentage drug releases after 8 hours was 83.21%, 73.86%, 64.78%, 52.68% and 58.76% of formulations F1 to F5 respectively. It was apparent that in-vitro release of ofloxacin lipospheres showed a very slow and the followed controlled drug release. Based on the drug encapsulation, particle size morphology and in vitro release, formulation F4 was selected as an optimum formulation. Thus lipospheres of ofloxacin (F4) was found to be spherical, discrete and free flowing and able to control the drug release effectively.

 

Fig 1: Photomicrographs of Lipospheres Containing Ofloxacin (F4)

 

Fig 2: Scanning Electron Micrograph of Lipospheres Containing Ofloxacin (F4)

 

Fig 3. Dissolution Profile of Ofloxacin Lipospheres

 

CONCLUSION:

Lipospheres prepared by melt dispersion, the use of different types of stabilizer and different concentration of lipid affected particles size and encapsulation efficiency. The use of PVA as stabilizer allowed the formation of very small lipospheres and better yield, in these respect further experiments were performed to better investigate the experimental parameters involved in the formulation of lipospheres.

 

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Received on 04.03.2011       Modified on 18.04.2011

Accepted on 15.05.2011      © RJPT All right reserved

Research J. Pharm. and Tech. 4(8): August 2011; Page 1234-1236