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Formulation and evaluation of gelatin micropellets of aceclofenac: effect of process variables on encapsulation efficiency, particle size and drug release.

Sahoo SK, Jena MK, Dhala S, Barik BB - Indian J Pharm Sci (2008)

Bottom Line: The effect of drug: polymer ratio, temperature of oil phase, amount of gluteraldehyde and stirring time was studied with respect to entrapment efficiency, micropellet size and drug release characteristics.The micromeritic studies of micropellets show improved flow property.The entrapment efficiency, micropellet size and drug release profile was altered significantly by changing various processing parameters.

View Article: PubMed Central - PubMed

Affiliation: University Department of Pharmaceutical Sciences, Utkal University, Vani-Vihar, Bhubaneswar-751 004, India.

ABSTRACT
In the present study aceclofenac-gelatin micropellets were prepared by the cross linking technique using gluteraldehyde as cross linking agent and characterized by X-ray diffractometry, differential scanning calorimetry and scanning electron microscopy. The effect of drug: polymer ratio, temperature of oil phase, amount of gluteraldehyde and stirring time was studied with respect to entrapment efficiency, micropellet size and drug release characteristics. Spherical micropellets having an entrapment efficiency of 57% to 97% were obtained. Differential scanning calorimetric analysis confirmed the absence of any drug-polymer interaction. The micromeritic studies of micropellets show improved flow property. The entrapment efficiency, micropellet size and drug release profile was altered significantly by changing various processing parameters.

No MeSH data available.


Related in: MedlinePlus

X-RD curves of aceclofenac loaded micropellets and aceclofenac.(A) Aceclofenac-loaded micropellets and (B) aceclofenac
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Figure 0002: X-RD curves of aceclofenac loaded micropellets and aceclofenac.(A) Aceclofenac-loaded micropellets and (B) aceclofenac

Mentions: The resulting micropellets obtained by above procedure were free flowing in nature as Carr's index of all formulation lies in the range 4-12 (Table 1). Entrapment efficiency was found to increase by increasing polymer:drug ratio from 1:0.25 to 1:1 (Table 1). The same case was noticed with mean particle size. At higher polymer-drug ratio, large droplets were formed due to increased viscosity of polymeric phase and, hence an increase in the mean particle size. The temperature of the oil phase is one of the important process parameters, as good entrapment efficiency was found at low temperature (10°), which also contributed to hardness of micropellets. A sharp endothermic (Tpeak =153.67°) was observed for aceclofenac at the room temperature corresponding to its melting point 150-158° (fig. 1). In case of gelatin, exothermic peak was observed in the temperature range of 200-250°. The characteristic, well-recognizable thermal profile of the drug appeared at the temperature corresponding to its melting point in the aceclofenac gelatin micropellets showing thermal peak at 151.90° but with the loss of its sharp appearance. It appears that there is a significant reduction of drug crystallinity in the polymer matrix. The X-ray powder diffraction patterns of pure drug and formulation containing aceclofenac (fig. 2) reveals that the intensity of the peaks for the pure drug was sharp, but when it was incorporated into the polymer matrix, the drug peaks showed a loss of sharpness due to decreased crystallinity of the drug. SEM of drug-loaded micropellets revealed that the micropellets were spherical in shape. The drug release from micropellets prepared at lower drug: polymer ratios was faster than that of micropellets prepared at higher drug-polymer ratios because of the small size of the micropellets at lower drug: polymer ratios, which provided a large surface area for faster drug release (data not shown). Micropellets prepared at 60° showed faster drug release than the micropellets prepared at 10° as shown in (fig. 3). This result may be accredited to the deterioration of the micropellet wall by gluteraldehyde at higher temperature, which may lead to rapid release of drug with initial burst effect. It was found that increase in amount of cross linking agent decreases the release time. This result may be attributed to the higher degree of cross linking of gelatin at higher gluteraldehyde concentration, which retarded drug release from the pellets (fig. 3). The micropellets treated with gluteraldehyde for a longer period of time showed slower drug release as compared to micropellets treated for a shorter period of time as evident from (fig. 3). This may be due to improvement in hardness of micropellets at longer exposure time.


Formulation and evaluation of gelatin micropellets of aceclofenac: effect of process variables on encapsulation efficiency, particle size and drug release.

Sahoo SK, Jena MK, Dhala S, Barik BB - Indian J Pharm Sci (2008)

X-RD curves of aceclofenac loaded micropellets and aceclofenac.(A) Aceclofenac-loaded micropellets and (B) aceclofenac
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3040878&req=5

Figure 0002: X-RD curves of aceclofenac loaded micropellets and aceclofenac.(A) Aceclofenac-loaded micropellets and (B) aceclofenac
Mentions: The resulting micropellets obtained by above procedure were free flowing in nature as Carr's index of all formulation lies in the range 4-12 (Table 1). Entrapment efficiency was found to increase by increasing polymer:drug ratio from 1:0.25 to 1:1 (Table 1). The same case was noticed with mean particle size. At higher polymer-drug ratio, large droplets were formed due to increased viscosity of polymeric phase and, hence an increase in the mean particle size. The temperature of the oil phase is one of the important process parameters, as good entrapment efficiency was found at low temperature (10°), which also contributed to hardness of micropellets. A sharp endothermic (Tpeak =153.67°) was observed for aceclofenac at the room temperature corresponding to its melting point 150-158° (fig. 1). In case of gelatin, exothermic peak was observed in the temperature range of 200-250°. The characteristic, well-recognizable thermal profile of the drug appeared at the temperature corresponding to its melting point in the aceclofenac gelatin micropellets showing thermal peak at 151.90° but with the loss of its sharp appearance. It appears that there is a significant reduction of drug crystallinity in the polymer matrix. The X-ray powder diffraction patterns of pure drug and formulation containing aceclofenac (fig. 2) reveals that the intensity of the peaks for the pure drug was sharp, but when it was incorporated into the polymer matrix, the drug peaks showed a loss of sharpness due to decreased crystallinity of the drug. SEM of drug-loaded micropellets revealed that the micropellets were spherical in shape. The drug release from micropellets prepared at lower drug: polymer ratios was faster than that of micropellets prepared at higher drug-polymer ratios because of the small size of the micropellets at lower drug: polymer ratios, which provided a large surface area for faster drug release (data not shown). Micropellets prepared at 60° showed faster drug release than the micropellets prepared at 10° as shown in (fig. 3). This result may be accredited to the deterioration of the micropellet wall by gluteraldehyde at higher temperature, which may lead to rapid release of drug with initial burst effect. It was found that increase in amount of cross linking agent decreases the release time. This result may be attributed to the higher degree of cross linking of gelatin at higher gluteraldehyde concentration, which retarded drug release from the pellets (fig. 3). The micropellets treated with gluteraldehyde for a longer period of time showed slower drug release as compared to micropellets treated for a shorter period of time as evident from (fig. 3). This may be due to improvement in hardness of micropellets at longer exposure time.

Bottom Line: The effect of drug: polymer ratio, temperature of oil phase, amount of gluteraldehyde and stirring time was studied with respect to entrapment efficiency, micropellet size and drug release characteristics.The micromeritic studies of micropellets show improved flow property.The entrapment efficiency, micropellet size and drug release profile was altered significantly by changing various processing parameters.

View Article: PubMed Central - PubMed

Affiliation: University Department of Pharmaceutical Sciences, Utkal University, Vani-Vihar, Bhubaneswar-751 004, India.

ABSTRACT
In the present study aceclofenac-gelatin micropellets were prepared by the cross linking technique using gluteraldehyde as cross linking agent and characterized by X-ray diffractometry, differential scanning calorimetry and scanning electron microscopy. The effect of drug: polymer ratio, temperature of oil phase, amount of gluteraldehyde and stirring time was studied with respect to entrapment efficiency, micropellet size and drug release characteristics. Spherical micropellets having an entrapment efficiency of 57% to 97% were obtained. Differential scanning calorimetric analysis confirmed the absence of any drug-polymer interaction. The micromeritic studies of micropellets show improved flow property. The entrapment efficiency, micropellet size and drug release profile was altered significantly by changing various processing parameters.

No MeSH data available.


Related in: MedlinePlus