Formulation and Evaluation of Microspheres Containing Mefenamic Acid by Inotropic Gelation Method

Chandrashekar C. Patil¹*, Katte Shubha¹, Ashwini. S. G¹, Santosh Karajgi¹, S.B. Shirsand²

¹B.L.D.E.A’s SSM College of Pharmacy,Vijayapur – 586101.

²HKES’s MTRIPS, Kalaburagi – 585105.

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

ABSTRACT:

Drugs with a narrow absorption window in the gastrointestinal tract (GIT) will have poor absorption. For these drugs, gastro retentive drug delivery system offers the advantage in prolonging the gastric emptying time. Losartan potassium is prescribed to treat hypertension. The current study was projected to prepare a Losartan potassium gastro retentive drug delivery system (GRDDS) of floating tablets was planned to enhance the gastric residence time, thus prolong the drug release. Losartan potassium effervescent floating tablets were prepared by utilizing the direct impression method, using polymers such as HPMCk15, xanthan gum, microcrystalline cellulose, and Sodium carbonate, with lubricants such as magnesium stearate and talc. In the present study, sodium bicarbonate was incorporated as a gas generating agent. And combination of sodium bicarbonate and citric acid was found to achieve optimum in vitro buoyancy. Total eight formulations were designed and evaluated for pre-compression parameters known as angle of repose, bulk density, tapped density, Hausner's ratio, compressibility index, and post -compression parameters are uniformity of weight variation, hardness, thickness, friability, floating lag time, and in vitro dissolution investigation and FTIR along with DSC is carried out

KEYWORDS: Losartan potassium, Floating tablets, Buoyancy, Direct compression, HPMCk15, xanthan gum.

INTRODUCTION: 

FLOATING DRUG DELIVERY SYSTEM (FDDS)

The most promising, secure, and efficient method of drug delivery is thought to be oral administration. Various factors, including the gastric emptying process, the gastrointestinal transit time of the dose form, and the drug release from the oral cavity, may affect the effectiveness of oral medication delivery, dose type and site of medication absorption. The majority of oral dose forms have a number of physiological restrictions, including variable gastrointestinal transit, which results in non-uniform absorption profiles, partial drug release, and shorter residence times of the dosage form in stomach.¹ As a result, medications with absorption windows, particularly those found in the upper part of the small intestine only absorb a portion of their dosage before passing through the absorption site.

Wide inter and intra-subject variability is seen as a result of numerous factors that influence the stomach emptying of dose forms in humans. Such significant variability may cause non-uniform absorption as many medications are well absorbed in the upper region of the gastrointestinal tract, making the bioavailability uncertain. Therefore, a useful delivery method would be one that has the capacity to regulate and extend the gastric emptying period. And is capable of delivering medications to the absorption site (the upper section of the small intestine).² Many FDDS have been developed recently, utilizing a variety of technologies, each with their own benefits and drawbacks. Examples include single and multiple unit gas generating systems, single and multiple unit hollow microspheres, and raft forming systems ³. FDDS is a medication formulation that uses hydrocolloids that create gels to stay buoyant in the stomach contents.

Table No-01- Formulation Table

Sr. No	Ingredients	F1	F2	F3	F4	F5	F6	F7	F8
1	Losartan potassium	10	10	10	10	10	10	10	10
2	HPMC K15	45	50	55	60	40	-	70	80
3	Xanthan gum	45	55	60	35	40	65	-	50
4	MCC	40	25	15	35	50	65	60	-
5	Sodium bicarbonate	90	90	90	90	90	90	90	90
6	Citric acid	15	15	15	15	15	15	15	15
7	Lactose	3	3	3	3	3	3	3	3
8	Magnesium stearate	1	1	1	1	1	1	1	1
9	Talc	1	1	1	1	1	1	1	1

MATERIAL AND METHOD:

Preparation of standard curve of mefenamic acid in PH 1.2 (0.1 N HCL):

100 mg of mefenamic acid was accurately weighed and dissolved in 100 mL of ethanol in a 100 mL volumetric flask.  This is primary inventory solution containing one thousand  µg/ml. from this number one stock answer, 1 ml was pipetted out and transferred to a 100 ml neither volumetric flask, and the volume was changed  to 100 ml with 0.1 N HCL containing the attention of 10 µg/ml. ( 2^nd inventory solution ).⁴

From second stock solution aliquots corresponding to 1-5 µg ( 1,2,3,4,5,6 ml ) were pipette out into a sequence  of 10 ml volumetric flask and volume where made up to 10 ml with 0.1 HCL. The absorbance of these solutions was calculated at 285 nm using a UV – visible spectrophotometer against o.1 HCL as a blank solution. The calibration curve was then plotted, with concentration in g/ml on the X axis and absorbance on the Y axis.

Preparation of Losartan Potassium Floating Tablets:

All the ingredients needed to make 20 tablets were precisely weighed and properly combined after passing through sieve number 22.In order to achieve uniformity. The required quantity of losartan potassium, i e, the active component, and the polymers (xanthan gum, HPMC k15, or a combination of these polymers) were precisely calculated and completely combined. Later, a ^{precise quantity of the effervescent substance NaHCO}3 ^{was added to the powder and it was} thoroughly mixed. After that, the mixture was evenly blended with the diluent, i e, lactose. The tablet formulation was then lubricated with talc and magnesium stearate (Table 1). And finally the powder was pressed in rotary tablet punching machine.⁵

Characterization of pre compression of losartan potassium floating tablet:

1. Bulk Density: It refers to Packing of particles. Equipment for measuring bulk density was used to assess the formed granules' bulk density.⁶ the dosage is provided by and is represented in gm/ml.

2. Tapped Density: The tablet mixture was weighed and placed in a graduated cylinder. The drug volume was recorded. The cylinder was then exposed to 100, 200 and 300 taps in a tap density apparatus.

3. Hausner's Ratio: It is a measurement of the frictional resistance of the tablet blend. The optimal range should be between 1.2 and 1.5. The ratio of tap density to bulk density was used to calculate it.

4. Carr's Index: The ability of powder to be compressed was measured using the Hausner ratio and compressibility index. Change in volume, which results from packing rearrangement during tapping, was used to assess the packing ability of tablet.

5. Angle of Repose: The angle of repose of powder was measured using the funnel method. The carefully measured granules were placed in a funnel. The funnel's height was modified such that its tip just touched the apex of the heap of the powder (2.0 cm above hard surface). The powders were permitted to freely pour onto the surface through the funnel. The diameter of the powder cone was measured. And the angle of repose was determined.

Characterization of Post - Compression Parameters of Losartan Potassium Floating:

1. Hardness: Using a Pfizer hardness tester, the hardness of the produced product was determined. For investigations on hardness uniformity, five produced floating tablets were employed. To determine the mean, standard deviation, and percentage of friability, the hardness data was employed. It was expressed as kg/cm2. A random sample of three tablets was chosen, and their hardness was measured.

2. Thickness: Ten tablets were randomly chosen for thickness uniformity testing from the prepared formulation and were measured in millimeters using a Vernier caliper. Mean and standard deviation were calculated using the data that was obtained.⁷

3. Friability: Utilizing the Roche Friabilator, the friability of the tablets was assessed. It is expressed. In percentage (%) form, In order to perform the friability test, twenty tablets   were first weighed and placed into the equipment. The tablets were weighed again after 4 minutes of operation with a 25 rpm friabilator.

4. Weight variation: To investigate weight variation twenty tablets from each formulation were individually weighed (WI) and recorded using an electronic balance. It was calculated by their average weight (WA). The following formula was used to obtain the percent weight variation.

5. Drug Content Uniformity: Ten tablets were individually measured and crushed to ensure uniform drug content. A volumetric flask with a 100 ml capacity and 0.1 N HCl was filled with powder that was equal to 50 mg of losartan potassium. A 0.45 m thick cellulose acetate membrane was used to filter the fluid. Additionally, 1 ml of the aforementioned solution was diluted to 100 ml with 0.1 N HCl, and the drug content of the resulting solution was assessed using a UV spectrophotometer at 205 nm⁸.

6. Floating Time: The amount of time that tablets float over medium is known as the floating time. In order to simulate the gastric environment, a tablet was added to 900 ml of 0.1N HCl in a vessel of a USP dissolving type II apparatus. The equipment was then operated at 100 rpm at 37 degrees C to determine the floating time. Using a stopwatch, time was measured. Six tablets (n 14 six) were used in the test. There were calculated mean and standard deviation⁹.

7. Floating \ Buoyancy Lag Time: The total amount of time that a dosage form remains buoyant is known as Total Floating Time. Floating Lag Time (FLT) or Buoyancy Lag Time (BLT) is the time it takes for a dosage form to appear on the surface of a medium (TFT). The floating lag time was used to calculate the in-vitro buoyancy. The tablets were added in a 100 ml beaker with 0.1N HCL. The floating lag time was calculated as the amount of time needed for the table to float and rise to the surface. Total floating time was calculated as the amount of time the dose form continuously floats on the surface of medium.¹⁰

8. Swelling Index: Once the tablet weight is determined (W1), it was put in the USP dissolution apparatus II with 900 ml of 0.1N HCl to determine the swelling index. The weight of the tablets was then measured at various time intervals, including 1hr, 2hr, 3hr, 4hr, 5hr, 6hr, 7hr, and 8hr ( W2), after using blotting paper to remove extra liquid. The following formula from Equation was used to calculate swelling index.

9. Bulk density was determined by placing perceived granules into a graduated cylinder and measuring the volume and weight as it is. The bulk density was calculated.

1. Tapped density:

Powder was introduced into measuring cylinder. After the initial volume was observed, the cylinder was allowed to fall under its own weight on the hard surface from the height of 2.5 am at 2^nd intervals. The tapping was continued until no further change in the volume was noted. The tapped density was calculated by using following formula. ¹¹

Tapped density = weight of powder / tapped volume of packing. And compressibility index of granules was determined by Carr’s compressibility index. Carr’s index = ([Tapped bulk density – bulk density)] × 100)/ TBD.

2. Particle size:

The microsphere were analyzed for their size and polydispersity index on zetasizer nano, Malvern instruments, based on photon correlation spectroscopy, at a scattering angle of 90⁰ and temperature of 25⁰ measurements were carried out both for fresh and air dried sample a 0.05% ( w/v ) tween 80 water solution in order to prevent precipitation during the measurements. The formulated microsphere evaluated by Manipal University.

3. Zeta potential:

The surface charge of the microspheres was determined with zetasizer nano ZS, Malvern instruments were carried out in an aqueous solution of KCl0.1N. Immediately before the determination microsphere was diluted with KCl solution. The measured values were corrected to a standard reference for temperature of 20⁰.¹²

4. Entrapment efficiency:

The prepared formulation was examined for entrapment efficiency. 10 mg of the prepared formulation was taken in equivalent quantity of 7.4 phosphate buffer. The suspension is ultra-centrifuged for 40 minutes.

5. Scanning electron  microscopy:

Scanning electron microscopy made to obtain photomicrographs of the mefenamic acid loaded microspheres. Scanning electron microscopy is used to determine the shape, size, and surface morphology of the microspheres.¹³

6. Fourier transform infrared spectroscopy : (FTIR)

The FTIR technique is used to measure the absorption of various infrared radiations by the target material, to produce on infrared spectrum which can be used to identify functional groups and molecular structure in the sample. The FTIR spectra of the pure and mefenamic acid.

Formulated microsphere were recorded using the FTIR 8400S (Shimadzu, Japan). The FTIR spectra were recorded between 4000 and 400 cm ^-1.

7. Differential scanning calorimetry:

The differential scanning calorimetric Q2000 V24.2 build 107 apparatus was used to perform differential scanning calorimetric on mefenamic acid microsphere.  Differential scanning calorimetric of the mefenamic acid and excipients to study the interaction between components.¹⁴

8. In vitro release study:

In vitro release study of mefenamic acid microsphere prepared by inotropic gelation method. The dissolution rate testing apparatus was employed to study of mefenamic acid using phosphate buffer PH 1.2 for 2 hr. and the buffer solution PH 7.4 as a dissolution medium. 50 mg equivalent of mefenamic acid microsphere was taken and dissolution test was being carried out at 100rpm maintained at 370c+ 0.5 c. 5ml of sample were withdrawn at specific time interval for 12 hrs. The concentration was determined spectrophotometrically at 285 nm. The same procedure was repeated for other formulation also.¹⁵

Result:

Mefenamic acid was prepared by ionotropic gelation method using sodium alginate, hydroxyl propyl methyl cellulose and calcium chloride. The drug Mefenamic acid was scanned between 200-400nm in both 0.1N HCL phosphate buffer and ph 7.4 and λ max of 285 was selected for further studies. The calibration curve if Mefenamic acid was performed in 0.1 N HCL of PH 1.2 phosphate buffer and phosphate buffer of PH 7.4. The r² values were 0.993 and 0.956; slope values were 0.0194 and 0.0572. The r² values suggest that there is linearity between drug concentration and corresponding absorbance. Study of micrometric properties the values of angle of repose of all of formulation within the range 12.10 to 15.42. And bulk density car’s index and Hausnar ratio also support the good flow properties these are shown in table no 2 and figures 1-3.

Table No-2: Evaluation of granular properties

Formulation no	Angle of repose (Ѳ)	Bulk density (g/ml)	Tapped density (g/ml)	Carr’s index	Hausner’s ratio
1	14.25	0.57	0.60	5	1.14
2	15.42	0.61	0.72	19.14	1.19
3	15.12	0.72	0.76	5.78	1.05
4	13.42	0.67	0.75	10.66	1.18
5	12.29	0.70	0.79	12.48	1.31
6	12.54	0.71	0.81	13.35	1.13
7	12.10	0.68	0.75	8.75	1.07

Fig No: 1: Formulation f3 drug + Polymer and Formulation f3 coating guar gum

Fig No: 2 DSC of pure drug and DSC f3 Formulation

Fig No-3: Cumulative percent drug released vs time plots of formulation F1, F2, F3, F4, F5, and F6

DISCUSSION:

Preparation of microsphere of Mefenamic acid by ionotropic gelation technique and evaluation.The microsphere were subjected to the evaluation for drug entrapment efficiency, particle size, in-vitro dissolution and characterized for FTIR Studies, Scanning electron microscopy, differential scanning calorimetry.The prepared formulations were evaluated for entrapment efficiency  F1 to F7 was found to be in the range of 65 % to 86%. Among all formulation F3 formulation was showing highest entrapment efficiency. Mefenamic acid microsphere f3 was selected as the optimized formulation which having a size of 353.5 Diameter (nm) in figures no 3. The drug polymer interaction was studied by FTIR analysis. FTIR studies confirmed that, there was no such interaction between drug and polymer used for microsphere formulation. The entire polymer used was compatible with the drug. The DSC analyzes of plane Mefenamic acid microsphere was carried out and the result is shown in figure no 9 as the graph shows curve under the negative zone. It is predicted as endothermic peak, that if formulation containing heat absorbability material. The melting point 197⁰ C showed that F3 formulation having polymer which is amorphous in nature and uniformly dispersed. In vitro dissolution studies of all batches of microspheres were shown in table 9.0 to 9.3 and figure.

In-vitro drug release of F1 to F7 was found to be respectively in the range of 74.03% to 94.26%, among all formulation, F3formulation was found to be 12 hr with 94.26% drug release rate. And the drug release kinetics data of optimized formulation F3 was fitted to zero order kinetic. Based on regression co- efficient values

CONCLUSION:

Formulation and evaluation of microsphere containing Mefenamic acid was successfully prepared using sodium alginate in combination with the hydroxypropyl methyl cellulose by inotropic gelation technique. The in vitro dissolution data showed sustained release of the formulation up to 12 hr. The microsphere was prepared without the use of organic solvents.

The prepared microsphere was evaluated for drug entrapment efficiency, particle size analysis, Scanning electron microscopy, differential scanning calorimetry and FTIR. FTIR studies confirmed that, there was no interaction between drug and polymer, in the formulation of F1 to F7 Among all formulation F3 formulation show satisfactory results.

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Received on 22.07.2023            Modified on 08.12.2023

Accepted on 14.02.2024           © RJPT All right reserved

Research J. Pharm. and Tech 2024; 17(4):1812-1816.

DOI: 10.52711/0974-360X.2024.00288