Ethiopia is one of the countries where cactus grows naturally. Cactus pear (Opuntia spp.),rnCactaceae family, is a plant with an impressive genetic diversity of over 400 species. Cactaceaernare well adapted to arid and hot drylands, where the plants have a marked capacity to withstandrnprolonged drought. The peculiar feature of the plant to adapt such areas is because of thernpresence of mucilage in specialized cells of the cladodes. Mucilage is a complex carbohydraternwith a highly branched structure, which contains varying proportions of L-arabinose, Dgalactose,rnL-rhamnose and D-xylose, as well as galacturonic acid in different proportions. Itrnswells in water and form viscous mass. Hence, recently an attention is being paid for its potentialrnuse in industry: food, cosmetic and pharmaceutical sectors.rnThe objective of this study is to determine the physico-chemical properties of mucilages ofrnOpuntia ficus-indica and Opuntia stricta, the two most abundant cactus species in Ethiopia, andrnevaluate their suspending ability in pharmaceutical suspensions.rnThe physico-chemical properties of the mucilages were compared between themselves. Thernsuspending abilities of the mucilages were compared with NaCMC. The dissolutions of thernsuspensions were performed using the USP paddle method at 25 rpm.rnThe yield of mucilage from both Opuntia spp. was found to be comparable. The solubility andrnSP of the mucilages were also studied. With increase in temperature the solubility increased andrnwas comparable in both mucilages. However, at all the treatment levels the SP were higher inrnmucilage of OS than that of OFI the differences of which were statistically significant. At 100%rnRH the moisture sorption property of OFI and OS were 95.4% and 76.9%, respectively. The pHrnvalues of both mucilages were found to decrease upon increasing mucilage concentration whichrnat 12% (w/v) dispersions were 5.57 and 5.87 for OFI and OS, respectively. The results showedrnthat these pH values are to be classified within low acid group. The conductivity, at 12% (w/v),rnof OFI was found to be 13.12 mS/cm while that of OS was 9.31 mS/cm. The apparent viscositiesrnat 12% (w/v) were 9,017 mPas and 10,060 mPas for OFI and OS, respectively. The apparentrnxrnviscosities of the dispersions decreased with increase in shear rates which rendered therndispersions a pseudoplastic flow.rnThese physico-chemical properties of the mucilages can signal on their potential use inrnpharmaceutical formulations especially suspensions. Hence, Paracetamol suspensions using thernmucilages and NaCMC as suspending agents were formulated. The apparent viscosities of thernsuspensions in all the suspending agents concentration levels and applied shear rates were in thernorder of NaCMC>OS>OFI with non-Newtonian flow and accordingly the flow rates of thernsuspensions were in the order of OFI>OS>NaCMC. The sedimentation volumes (%) of thernsuspensions in all the suspending agent concentration levels were higher for OS followed by OFIrnand then NaCMC. The high sedimentation volumes (%) of suspensions, in turn, werernaccompanied by ease of redispersibility of that order. The effect of electrolyte on sedimentationrnvolume (%) had dual effect. It was only the suspensions that had NaCMC that showed increasernin sedimentation volume (%) in all molar NaCl concentration. However, in suspensions that hadrnmucilages of OS and OFI, an initial increase in sediment volumes (%) were accompanied byrndecrease after 1x10-3M and 1x10-2M of NaCl, respectively. Moreover, the effect of pH onrnsedimentation volume (%) was addressed. Hence, the suspensions from NaCMC were stable inrnacidic media while suspensions from OFI and OS were stable in basic media. Dissolution of thernsuspensions which had mucilages attained the acceptable ranges (â‰¥ 80% drug release in 30 min)rnin 5 min. Similarly, except A6 formulations A2, A3, A4 and A5 have attained the limit but thernrelease was not as quick as the previous formulations.rnHence, it can be concluded that mucilages of Opuntia spp. (Opuntia ficus-indica and Opuntiarnstricta) can be used as alternatives to NaCMC as suspending agent in suspension formulations.rnKey words: Cactus, Mucilage, Opuntia spp., Sedimentation volume, Suspension, Suspendingrnagent