Increased intraocular pressure (IOP) is a significant risk factor for the development of glaucoma. Timolol maleate is a beta-adrenergic receptor blocking agent and it is used for the treatment of glaucoma in order to reduce the elevated IOP that is characteristic of this eye disease. Systemic toxicity from topical timolol occurs more frequently than local toxicity and can affect the pulmonary, cardiac and central nervous systems. The objective of the present study, therefore, was to formulate multilamellar vesicles (MLVs) liposomal preparations of timolol maleate using their advantage of being less toxic compared with non-liposome-based drugs to be applied topically and to evaluate the in vivo performance of the prepared liposomes to extend the time of reduced IOP of glaucomatous rabbit's eye measured using a standard Shiotz tonometer. The encapsulation efficiency of MLVs was measured using a spectrophotometric technique. Differential scanning calorimetry (DSC) was used to monitor the effects of timolol maleate in the absence and presence of cholesterol on liposome thermal behaviour. Positively charged MLVs of timolol in the presence of a lower amount of cholesterol (DPPC(7):Chol(2):Timolol(2):SA(1) molar ratio) were found to be superior compared with other formulations in extending the ocular hypotensive effect approximately for 1 week (160 h) which encourages its physiological effectiveness. The increase of the cholesterol molar ratio in the prepared liposomal formulations serves to decrease the permeability of the lipid bilayer that is manifested by a low rate of drug release, an increased percentage of entrapment efficiency and a consequently lower bioavailability.
Ifosfamide is an alkylating oxazaphosphorine antitumor prodrug. Although it is an effective chemotherapeutic agent, it has been shown to induce many side effects. The objective of the present study, therefore, was to investigate the possible protective roles of lecithin and quercetin either singly or combined against ifosfamide-induced molecular structure changes in retina of female rats using Fourier transform infrared spectroscopy (FTIR). Seventy female albino rats were randomly divided into seven groups. Ifosfamide (Ifo; 80mg/kg b.wt.) was administrated for five consecutive days intraperitoneally (i.p.), while quercetin (50mg/kg b.wt.) and lecithin (100mg/kg b.wt) were given orally either singly or in-combination with IFO for six consecutive days. Our results indicate that Ifosfamide was affected on the lipid components of the retina, NH-OH region changes revealed unusual interface/binding mechanism that related to different surrounding environment due to ifosfamide intraperitoneal injection. The co-administration of Lec+Que with the intraperitoneal injection of Ifosfamide preventing the side effect of Ifosfamide. We suggest that synergistic effect of quercetin and lecithin in the combined therapy results in marked neuroprotective effect in part through its antioxidant properties and down regulation of molecular structure in retina.
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