Evaluate the performance of the authentication protocols in cellular networks according to the quality of service

LTE’s success as a high throughput, and umbrella technology for wireless networks is highly affected by the researchers’ capability of solving its current security vulnerabilities. Mutual authentication was adopted by mobile networks to overcome vulnerabilities exploited by “IMSI catcher” and other active attacks. 3GPP’s mutual authentication implementation in EPS AKA succeeded in enhancing the network’s security, but failed to cover weaknesses inherited from its predecessor (UMTS). One of those vulnerabilities is the passive capturing of IMSIs during user identification in the Authentication and Key Agreement protocol. Many researchers tried over the past years, to propose an alternative for EPS AKA, able to ensure high levels of security and offer acceptable QoS performance. In this paper, we will crypt-analyze (SPAKA and PBKP) which was claimed to solve EPS AKA’s privacy and mutual authentication weaknesses, then we will compare its QoS performance to EC-AKA and EPS AKA. Our proposed protocol “EC-AKA” is a real candidate to replace the current authentication and Key Agreement protocol, because of its excellent performance in all the studied parameters.

Formulation of methyldopa sustained release matrix tablets using hydrophilic polymers

The present study aims to develop sustained release (SR) matrix tablets of methyldopa using hydrophilic hydroxypropyl methylcellulose (HPMC), and to study the effect of some formulation variables (HPMC concentration and viscosity grade, combination with hydrophobic Ethylcellulose (EC) in different ratio, binder and lubricants concentrations) on the properties of prepared tablets. Matrix tablets were prepared by wet granulation method, and prepared granules and tablets were subjected to suitable physiochemical studies. Drug release kinetics showed that drug release mechanism for about all formulations was found to fit best to Higuchi model and drug release mechanism was anomalous diffusion based on release exponent value. The in-vitro dissolution studies showed that formulation F6 containing 15% of HPMC K100M and formulation F11 containing EC:HPMC K4M (5%:10%) were able to sustain the release of methyldopa up to 24 hours so these two formulations were selected as suitable formulations.

Formulation and evaluation of methyldopa sustained release matrix tablets

The objective of the present study was to formulate methyldopa sustained release matrix tablets using hydrophilic hydroxypropyl methylcellulose (HPMC) alone or in combination with hydrophobic ethyl cellulose polymer(EC). Matrix tablets were prepared by wet granulation method, and subjected to physiochemical studies. All formulations showed physiochemical properties which appear to be in compliance with pharmacopeial standards. The in-vitro dissolution studies showed that increase in concentration or viscosity of HPMC polymer led to decrease in the rate of drug release decreased. The results also revealed that Combination of HPMC K4M and EC slower drug release more than using HPMC K4M alone. Drug release kinetics of about all formulations correspond best to Korsemeyer-Peppas model and drug release mechanism was anomalous diffusion based on release exponent value.