DESIGN AND OPTIMIZATION OF PEDIATRIC CEFUROXIME AXETIL DISPERSIBLE TABLET CONTAINING ION-EXCHANGE RESIN

Objective: The aim of present work was to develop of pediatric cefuroxime axetil 125 mg dispersible tablets by using ion exchange resin as a taste masking agent and quality target product profile was defined based on the properties of the cefuroxime axetil. Methods: Initially, cefuroxime axetil and various resin complexes (DRC) were prepared with different conditions and evaluated for taste masking and drug loading. Optimized DRC was used to formulate the dispersible tablet. A 3 2 full factorial design was employed to study the effect of mannitol (X 1 ) and microcrystalline cellulose PH-101 (X 2 ) on drug release at 10 min and time taken to 80% drug release. In the present study, the following constraints were arbitrarily used for the selection of an optimized batch: Q 10 >65% and T 80%< Results: Among the various drug resins complex DRC-9 was found with less bitter taste which was containing kyron T-114 and among the all factorial batch F 30 min. Multiple linear regression analysis, ANOVA and graphical representation of the influence factor by 3D plots were performed by using Sigmaplot 11.0. Checkpoint batch was prepared to validate the evolved model. 7 showed highest drug release at 10 min (Q 10 ) and lowest time taken to 80% drug release (T 80 ) hence batch F 7 Conclusion: The results of full factorial design indicate mannitol and MCC PH-101 have a significant effect on drug release. was selected as an optimized batch and it’s found to be stable in the stability evaluation.


INTRODUCTION
Oral route of drug administration is the most appealing route for drug delivery. Among the various dosage forms tablet is one of the most preferred dosage forms because of its ease of manufacturing, convenience in administration, accurate dosing, and stability compared with other forms etc. A number of orally administered drugs exhibit natural bitter taste that creates an unpleasant feeling in the mouth [1,2]. Therefore, it is necessary to reduce or mask the bitterness for enhancing patient acceptability and improving oral palatability of bitter drugs. Cefuroxime axetil has a broad spectrum antibacterial agent with a bitter taste, so it is necessary to mask the bitter taste for pediatric patients [3,4]. Different methods have been suggested for masking of the bitter taste, which includes coating, inclusion complexes, molecular complexes, solid dispersion, microencapsulation, multiple emulsions, liposome's, Prodrugs and mass extrusion method from that ion exchange resin is one of most extensively method to overcome this problem [5,6].
The present study was aimed to prepare the drug-resin complex (DRC) of cefuroxime axetil and evaluate for taste and drug loading. It was compressed into tablets by direct compression method. A 3 2 full factorial design was employed to study the effect of mannitol (X1) and MCC PH-101 (X2) on drug release at 10 min (Q10) and time is taken to 80 % drug release (T80). In the present study, the following constraints were arbitrarily used for the selection of an optimized batch: Q10>65 % and T80%

Materials and reagents
Cefuroxime axetil was received as a generous gift from Lincoln pharmaceutical Ltd., Ahmedabad, Gujarat, India. Kyron T 114 and kyron T 134 was obtained from Corel pharma ltd., Ahmedabad, Gujarat, India. Microcrystalline cellulose PH 101 and mannitol were purchased from Astron chemicals, Mumbai, Maharashtra, India. All other materials and chemicals used were of either pharmaceutical or analytical grade.

Drug excipients compatibility study
The physicochemical compatibilities of the drug and excipients were tested by differential scanning calorimetric (DSC) analysis. Thermograms of cefuroxime axetil, drug-resin complex and drugexcipients physical mixture were derived from DSC with a thermal analysis performed by using an automatic thermal analyzer system (DSC 60, Shimadzu, Japan). The analysis was performed at a rate of 20 °C/min from 50 °C to 300 °C under a nitrogen flow of 25 ml/min [9,10].

Development and evaluation of drug-resin complex (DRC)
In the batch process, the activated resin was placed in a beaker containing deionised water and allows swelling for 30 min. accurately weighed cefuroxime axetil was added and stirred for different periods of time at various pH as shown in table 3. The mixtures were filtered and the residue was washed with deionised water to remove the loosely adsorbed drug from the surface. DRC was allowed to dry at room temperature and was stored in a tightly closed container. DRC was evaluated for taste and drug loading. Taste of drug-resin complexes was subjected to gustatory sensory evaluation test performed by a panel of ten volunteers. The volunteers were selected randomly and instructed to rate the samples as per the taste evaluation scale. For drug loading analysis 50 mg of DRC was added in 0.1 N HCL and kept in a sonicator for 30 min. The samples were withdrawn and taking absorbance at 277 nm [11,12].

Preliminary trail of cefuroxime axetil 125 mg dispersible tablets
Cefuroxime axetil 125 mg dispersible tablets was prepared according to the formula given in table 1. All the ingredients were passed through 60# sieve separately and mixed in geometrical order. First MCC, mannitol, SSG were mixed together then add the DRC and mixed for 10 min. Finally, sodium saccharin or aspartame, sodium stearyl fumarate or magnesium stearate and talc were mixed for 10 min. Compression was carried out using 11 mm punch set. All the batches were stored properly and evaluation was carried out [13,14].

Evaluation of cefuroxime axetil 125 mg dispersible tablets
Thickness, hardness, weight variation, % friability and disintegration test of the formulations were measured as described by Yadav K et al., Khar RK et al.,Madgulkar AR et al.,and Lakade SH et al.,.
Wetting time: It can be measured by using five circular tissue papers of 10 cm in diameter, which are placed in a petridish of 10 cm diameter. 10 ml of eosin solution is added to the petridish. A tablet is carefully placed on the surface of the tissue paper. The time required for water to reach the upper surface of the tablet is noted as the wetting time.
The fineness of dispersion: It is an assessment of the grittiness which arises due to the disintegration of the tablet into coarse particles. The test was performed by placing two tablets in 100 ml water and stirring it gently, till the tablets get completely disintegrated. The formulation was considered to form a smooth dispersion if the complete dispersion passes through a sieve screen with a nominal mesh aperture of 710 μm without leaving any residue on the mesh.
In vitro dissolution study: Drug release studies were carried out using by USP II dissolution test apparatus at 37±0.5 °C and 50 rpm. In this study, 0.1 N HCl (pH 1.2) was used as a dissolution medium. Aliquots of 5 ml were withdrawn at predetermined time intervals and an equal amount of fresh dissolution medium was added. The solution was suitably diluted and assayed at 277 nm using a UV-Vis double-beam spectrophotometer.
Taste analysis: All the batches of tablets were subjected to the gustatory sensory evaluation test performed by a panel of ten volunteers. The volunteers selected randomly and instructed to rate the samples as per the taste evaluation scale [19,21].
Sodium Optimization of excipients amount by using 3 2 full factorial design A 3 2 full factorial design was used in the present study. Formulation of factorial batches was shown in table 2. On the basis of preliminary results, the amount of mannitol (X1) and the amount of MCC PH-101 (X2) were chosen as independent variables in 3 2 full factorial design, while % drug release at 10 min (Q10%) and time required for 80% drug release (t80). were taken as dependent variables. Multiple linear regression analysis, ANOVA and graphical representation of the influence of factor by contour plots were performed using Sigmaplot 11.0. The experimental runs and measured responses of 3 2
Optimized batch was packed in aluminum foil and was placed for stability study at 40˚C/75% RH for 3 mo. Sample was evaluated after 3 mo for physical parameters and In vitro dissolution. The dissolution profile of the product was compared using the similarity factor, f2, which was calculated by the following formula.
where the log is logarithm to the base 10, n is the number of time points, ∑ is summation over all time points, Rt is the mean dissolution value of the reference profile at time t and Tt is the mean dissolution value of the test profile at the same time point. The USFDA draft guidance document contains more information on the similarity factor (f2). The value of the similarity factor (f2) between 50 and 100 suggests that the two dissolution profiles are similar [25][26][27].

Drug-excipient compatibility study
Compatibility studies of pure drug with ion-exchange resin and other excipients were carried out prior to the preparation of taste masked dispersible tablet. Fig. 1 and fig. 2 shows DSC thermograms of cefuroxime axetil and kyron T-114, respectively. Fig. 3 and fig. 4 shows DSC thermograms of drug-resin complex and Drug-excipients physical mixture, respectively. The DSC analysis of the drug alone elicited a peak at 255.22 °C and complex of cefuroxime axetil with kyron T-114 shows peak of drug at 256.78 °C. Elicited peak of the physical mixture of DRC and other excipients was found to be at 254.16 °C. Thus, it was thought to indicate that there was no evidence of interactions between cefuroxime axetil, kyron T-114 and the used excipients. So, it can conclude that drug and other excipients are compatible which each other [28,29]. Trial batches of cefuroxime axetil-resin complex were prepared using different drug-resin ratio, different resins, pH and temperature. Taste and % of drug loading of all the formulation were shown in table 3. Indion-214 showed a higher percentage of drug loading but it cannot mask the bitter taste. The same condition was found with kyron T-134. Among the all batches DRC-9 showed less bitter taste and 92.70% of drug loading may be due to drug got ionised and cross-linked with kyron T-114 at pH 9. So, DRC-9 was use for further studies to prepare cefuroxime axetil dispersible tablet [30].  Table 4 shows the results of pre-compression, post-compression and In vitro drug release at 45 min of preliminary trail batches of dispersible tablets. The hardness and friability of all the formulation was found to be in a range of 1.9 to 3.9 kg/cm 3 and 0.30 to 0.70 respectively. Trail batches of dispersible tablets indicate that hardness dependent on MCC and mannitol concentration. Batch X5 and X6 shows less disintegration time compared to batch X1, X2, X3 and X4. Croscarmellose Sodium was increased in batch X7 but it will not impact on disintegration time. So, sodium starch glycolate was used as super disintegrants for further Preliminary trial batch. Sodium starch glycolate further increase in batch X11 and X12 but it decreases hardness of tablet and less impact on disintegration time. In Batch X13 and X14; MCC and mannitol was taken as filler for tablet. X13, X14 gave 94.61% and 89.65% drug release in 45 min, respectively. The results of preliminary study revealed that MCC or mannitol alone was not sufficient to achieve the desired release profile. Hence, further trials were carried out using combination MCC and mannitol in order to understand their effect and to optimize concentration of both for desired release profile [31,32].

2 full factorial design model evaluation
A statistical model incorporating interactive and polynomial terms was used to evaluate the responses: where, Y is the dependent variable, bo is the arithmetic mean response of the 9 runs and any bi is the estimated coefficients for the related factor Xi. The main effects (X1 and X2) represent the average result of changing one factor at a time from its low to high value. The polynomial terms (X1 +b12X1X2 2 and X2 2 ) are included to investigate nonlinearity. The interaction term "X1X2" shows how the response changes when the two factors change simultaneously. Evaluation data of pre-compression and post-compression parameters of factorial batches and In vitro % drug release were presented in table 5 and table 6. Table 7 describes the effect of independent variables on dependent variables by 3 2 full factorial designs. The fitted equations (full model) relating the responses that is % drug release at 10 min (Q10%) and time required for 80% drug release (min) (T80) to the transformed factor were shown in table 8. The polynomial equation can be used to draw conclusion after considering the magnitude of coefficient and the mathematical sign it carries (i.e. positive or negative). The results of ANOVA suggested that F values calculated for Q10% and t80% are 59.668 and 92.625, respectively (table 8). Tabulated F value was found to be 9.013 at α = 0.05. Calculated F values are greater than tabulated for all dependent variables therefore factors selected have shown significant effects. From the results of multiple regression analysis, it was found that both factors had statistically significant influence on all dependent variables as p<0.05 [33,34].   From the 3D plot ( fig. 5) and the regression coefficient values of factors, it was concluded that when MCC PH-101 concentration was increase that time drug release also increase due to its hydrophilic )-(3.501 X1X2) nature. For drug release at 10 min, the significance levels of the coefficients b11 and b22 were found to be P = 0.454, and 0.617 repectively, so they were omitted from the full model to generate a reduced model. The coefficients b0, b1, b2 and b12 significant at P<0.05; hence they were retained in the reduced model. [35,36]  From the 3D plot graph ( fig. 6) and the regression coefficient values of factors, it was concluded that when mannitol concentration was increase that time drug release decrease may be due to its very low hydrophilic nature. For time required for 80% drug release, the significance levels of the coefficients b11 and b22 were found to be P = 1.00, and 0.584 repectively, so they were omitted from the full model to generate a reduced model. The coefficients b0, b1, b2 and b12 significant at P<0.05; hence they were retained in the reduced model. [37,38]

Formulation of check point batch
To validate the evolved mathematical models, a check point batches CP1 was prepared and evaluated. The observed and predicted values for batch CP1 were shown in table 10. Good correlation was found between observed and predicted values shown in table 11. Hence, it was concluded that the evolved models may be used for theoretical prediction of responses within the factor space [22].

Selection of optimized batch in factorial design study
In the present study, the following constraints were arbitrarily used for the selection of an optimized batch: Q10>65 % and T80%<30 min. Batches F4, F5, F7, F8 and F9 met the selection criteria. Batch F7 showed higest % drug release at 10 min (69.149) and lowest time required for 80% drug release (25 min), Hence, Batch F7 was selected as an optimized batch. The optimized formulation was subjected to accelerated stability study.

Short term stability study
Batch F7 was kept for stability study. The in vitro release profile at initial and after 3 mo was compared using similarity factor, f2, value which was found to be 86.50. There is no significant difference in similarity factor. Evaluation parameter of stability parameter was shown in table 12.

CONCLUSION
The objective of the present investigation was to formulate, evaluate and optimize the cefuroxime axetil 125 mg dispersible tablets to achieve quick disintegration and fast release of the drug for paediatric patients. Kyron T-114 was used as teste masking agent that showed highest % of drug loading and test masking. These formulations were evaluated for the parameters like drug excipient compatibility study, thickness, hardness, weight variation, % friability, disintegration test, in vitro drug release and accelerated stability studies. On the basis of preliminary results, the amount of mannitol (X1) and the amount of MCC PH-101 (X2) were chosen as independent variables in 3 2

AUTHORS CONTRIBUTIONS
full factorial design, while % drug release at 10 min (Q10%) and time required for 80% drug release (t80), were taken as dependent variables. Multiple linear regression analysis, ANOVA and graphical representation of the influence of factor by contour plots were performed using Sigmaplot 11.0. From the results of multiple regression analysis, it was found that both factors had significant influence on all dependent variables. Check point batch was prepared to validate the evolved model. Batch F7 was selected as an optimized batch and it was found to be stable in the stability evaluation.
All the author have contributed equally