The large impact of moderate earthquakes in unstable shelf of north Egypt on human society provides a strong motivation to study and understand the systematics of their occurrence. In this study, we examine the correlation of north Egypt unstable shelf earthquakes using five geologic and geophysical data sets: a newly compiled age-province map, Bouguer gravity data, aeromagnetic anomalies, tectonic stress field, and GPS velocity rate measurements. Based on the qualitative and quantitative interpretation of these five data sets, we inferred that (1) although surface features disappeared of unstable shelf crust, Phanerozoic crust shows clear correlation of crustal age and earthquake frequency. (2) The seismic ages are during Precambrian and Paleozoic unstable shelf crust.(3) Seismicity is correlated with the major tectonic events in the geologic history of Egypt. Unstable shelf seismicity mainly (1) follows the NW-SE lineaments and (2) forms clusters at what have been termed stress concentrators (e.g., intersecting faults and igneous intrusions) at EN-WS and E-W structural trends. The correlation of seismicity with NW-SE-oriented lineaments implies that the unstable shelf seismicity is related to the accretion and rifting processes that have formed the Red Sea and Gulf of Suez which still records active rifting. An analysis of hypocentral depths for unstable shelf earthquakes shows that the frequency and moment magnitude of events are nearly uniform for the entire 5-30 km depths over which crustal earthquakes extend. We appreciate that the deep structure of the crust, in particular the existence of deeply penetrating faults, is the controlling parameter, rather than lateral variations in rheology or high pore pressure. We conclude that the distribution of the unstable shelf earthquakes in north Egypt is consistent with the existence of deeply penetrating crustal faults that have been reactivated in the present stress field. Future earthquakes may occur anywhere along the geophysical lineations that we have identified. This implies that seismic hazard is more widespread in the Nile Delta Basin and Cairo province of north Egypt than indicated by the distribution of limited and inaccurate historical seismicity.
Lornoxicam as a non-steroidal anti-inflammatory drug (NSAID) has the same side effects of this group if taken orally (GIT, renal, and hepatic disorders). Lornoxicam and its metabolites bind extensively to plasma albumin (99%), beside that, it has a relatively short half-life (3 to 5 hrs). The drug was formulated in mucoadhesive buccal patches using different polymers including, hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), hydroxypropylmethyl cellulose (HPMC), chitosan, polyvinyl alcohol (PVA), gelatin, sodium alginate and sodium carboxymethyl cellulose (Na CMC). The physical characteristics of the formulated patches as mass uniformity, patch thickness, surface pH, folding endurance, swelling, residence time as well as mucoadhesion (in-vitro and ex-vivo mucoadhesion force) were evaluated. The in-vitro release of the drug from the formulated patches was studied using the USP dissolution apparatus, and the results indicated that HEC, HPC and chitosan showed the lowest drug release (70%, 76%, and 81%, respectively) while gelatin, sodium alginate and Na CMC gave the highest release (nearly 100%). Permeation of lornoxicam formulated in different patches through rabbit buccal mucosa was also studied and the results showed that gelatin and chitosan patches resulted in the highest drug permeation. Kinetics of drug release from the different patches was found to follow zero order or diffusion kinetics.
Ketorolac tromethamine (KT) is one of NSAIDs that has GIT, renal and hepatic disorder if taken orally. The study aimed at avoiding the adverse effects of KT by formulating it in different topical dosage form such as gel (Sodium algnate, NaCMC, HPMC, Carbopol 934 and Pluronic F127), emulgel (O/W), microemulsion and cream (O/W and W/O). The interactions between KT, polymers and other ingredients used were studied using differential scanning calorimeter (DSC) and Infra red (IR) spectroscopy. The physical properties of these formulations appearance, homogeneity, pH and viscosity were studied. The in-vitro release of KT from these formulations through cellophane membrane was carried out. The kinetic study of KT release from these formulations was also studied. In-vitro study of KT permeation in diffusion cell using rat skin from the selected formulations was carried out. Physical investigation of KT and polymers indicated that no interaction between KT and polymers. Among the polymers used in gel formulations, HPMC and NaCMC gave the highest release rate of KT in-vitro, while pluronic F127 gave promising sustained release. In case of emulgel formulations, O/W emulgel base gave higher release than microemulsion base. Also in case of emulsion ointment base formulations, the release of KT from O/W base was higher than W/O type which gave the lowest release. In-vitro study of KT through the diffusion cell using rat skin as biological membrane, higher permeation was obtained in case of carbopol 934 gel and O/W emulgel comparison with pluronic F127 gel which gave the lowest permeation of KT.
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