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BackgroundEffective treatment of osteoarthritis necessitates both symptomatic relief and hindrance of joint degeneration progression. Non-steroidal anti-inflammatory drugs permit symptomatic relief only and can cause mucosal injury in the gut. Before absorption, diacerein (Dcn) is converted into rhein that counteracts cartilage degeneration without affecting prostaglandin production. Yet, low solubility and laxative action of unabsorbed rhein in the colon hindered its use. Thus, enhanced Dcn dissolution would allow absorption at the upper gut improving its bioavailability and possibly abolishing the laxative action.MethodsTherefore, self-nanoemulsifying drug delivery systems (SNEDDSs) with each of gelucire 44/14 (Glc) and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) at different drug:carrier weight ratios of 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10 were prepared by melt method and filled into hard gelatin capsules. The optimized binary systems were selected based on solid state characterization, scanning electron microscopy (SEM) and in vitro evaluation of the prepared SNEDDSs in comparison with their corresponding physical mixtures (PMs) and Dcn. The optimized systems were further examined with respect to their morphology, size distribution and ζ-potential. Moreover, the anti-inflammatory activity of the optimized systems against carrageenan-induced paw edema in rats was assessed through estimation of edema and edema inhibition percentages as well as histopathological examination and immunohistochemical localization of tumor necrosis factor-alpha (TNF-α) and caspase-3.ResultsSignificantly (P<0.05) enhanced in vitro drug release was recorded for SNEDDSs with either carrier when compared to Dcn and the corresponding PMs. SNEDDSs based on 1:10 Dcn:Glc and 1:8 Dcn:TPGS showed significantly (P<0.05) reduced edema and inflammation as well as expression of TNF-α and caspase-3 relative to positive control and Dcn pretreated groups.ConclusionThese SNEDDSs can be represented as potential oral drug delivery systems of Dcn for enhanced dissolution and anti-inflammatory activity against carrageenan-induced paw edema.

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The oral absorption and hence the oral bioavailability of carbamazepine (CBZ) is variable even after administration of rapidly dissolving formulation. This problem was attributed to supersaturation of CBZ and transformation to the less soluble carbamazepine dihydrate (CBD). Accordingly, formulation of sustained release products of CBZ is a promising approach to overcome this problem. Microsponges is an emerging formulation which can help in this direction. The aim of this work was to optimize the composition of microsponges for better encapsulation and sustained release of CBZ for oral administration. CBZ microsponges were prepared using quasi emulsion solvent diffusion technique with varying composition of ethyl cellulose and polyvinyl alcohol (PVA). Microsponges were evaluated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray diffraction. Production yield, entrapment e ciency and surface morphology of microsponges were assessed in addition to drug release. Optimum formulation was administered orally to albino rabbits to evaluate the oral bioavailability with reference to unprocessed CBZ. The Instrumental analysis re ected the encapsulation of CBZ in amorphous or molecularly dispersed form in the microsponges. The size and entrapment e ciency of the microsponges increased with increasing polymer contents. This was associated with reduction in CBZ release. Optimum formulation enhanced the oral absorption of CBZ. This was manifested by 2.6-fold increase in the area under the plasma concentration versus time curve compared to that of unprocessed CBZ. The study introduced microsponges as promising carriers for sustained oral delivery of CBZ.