LIPID MICROSPHERES FOR CONTROLLED RELEASE OF LIPID SOLUBLE DRUG: ACECLOFENAC MICROSPHERES

In the present work we aimed our investigation to prepare and evaluate the Lipid microspheres of an Anti-inflammatory drug i.e. Aceclofenac in order to control the drug release, to enhance the bioavailability and to minimize gastrointestinal side effects. For the preparation of Lipid microspheres, melt dispersion technique was used. Paraffin wax and stearic acid were used as excipients.
Preformulation studies were carried out in order to confirm the purity of Aceclofenac and to establish the compatibility between the drug and excipients by Infrared spectroscopy. The studies revealed that, drug and excipients were satisfactorily compatible.
The prepared Lipid microspheres formulations were evaluated for different parameters like particle size analysis, drug content, entrapment efficiency, and SEM, XRD, DSC, and in-vitro release studies.

Particle size was characterized by using optical microscope and found to be 43.60 m for optimized formulation. The drug content of the prepared formulations was within the acceptable range, and ensures dose uniformity. The formulations F5 and F6 showed maximum drug content. The entrapment efficiency of the Lipid microsphere formulations was found to be within in the range of 65.57% – 94.72%. The LMs observed through the SEM were found to be spherical with a smooth surface. XRD data indicates that the Aceclofenac is still present in its lattice structure in the physical mixture, where as it is completely amorphous inside the Aceclofenac Lipid microspheres. This may be due to the conditions used to prepare the Aceclofenac Lipid microspheres lead to cause complete drug amorphization. The thermal graphs of pure aceclofenac, formulation F6 containing Aceclofenac and its corresponding physical mixture showed endothermic peaks at 152.50, 149.10 and 152.00 0C, indicating the melting transition point of aceclofenac in all these three cases. Overall, the results of DSC studies confirmed almost similar physical state of Aceclofenac in all these three cases. Drug release from the Lipid microspheres depended on the wax payloads and the stearic acid levels. Lipid microspheres produced with paraffin wax alone showed slow drug release, ranging from 65.87%, to 67.87% respectively. The drug release from the Lipid microspheres in the presence of stearic acid was found to range from 70.21% to 86.22% respectively, indicating enhancement of drug release in the presence of the modifier. The correlation coefficient (r2) of these formulations showed an adequate fit to Zero order model as r2 value were in the range of 0.996-0.999. The stability data indicates that the formulations did not undergo any chemical changes or interaction during the study period. Therefore, no changes in physical appearances and residual drug content were noted.