OBJECTIVES: Terfenadine, as an antihistaminic agent. is widely used to control seasonal allergy such as rhinitis. Terfenadine is in fact a prodrug and is rapidly absorbed from the gastrointestinal tract It undergoes extensive first-pass metabolism in the liver to its active metabolite the carboxylic acid derivative fexofenadine. Sustained or CONTROLLED- RELEASE dosage forms favor the strategy of therapy by minimizing the side effects via reducing terfenadine plasma concen1ration which is the main cause of its cardiotoxicity as well as maximizing the patient compliance. However, few studies have been conducted to formulate the CONTROLLED-RELEASE dosage forms. Thus, in the current investigation in an attempt to formulate oral CONTROLLED-RELEASE terfenadine. METHODS: We have directly compressed terfenadine with a designated mixture of hydroxypropyl methylcellulose (HPMC) and magnesium stearate using 13.5, 54.0 and 67.5 MPa compression pressure. Also two conventiona tablets (home and foreign made) as well as the drug powder were included in the RELEASE studies. The content uniformity of the matrices and the tablets were assessed. Further, the RELEASE profiles of the prepared matrices were evaluated exploiting various classical kinetics models i.e., Weibull, Hixon-Crowell cube root, Higuchi square root of time, probability linear and log linear, first-order, zero-order and polynomial model comprising erosion and diffusion terms. Among the models used, the data was fitted best to the polynomial model with lag time. RESULTS: No significant difference was detected for content uniformity. The RELEASE of the drug from the matrices was markedly dependent on the compression pressure, that is the higher the pressure the lower is the RELEASE rate and hence the longer the complete RELEASE time. The complete RELEASE times were 480, 510 and 570 min for the compression pressure of 13.5, 54.0 and 67.5 MPa, respectively. The conventional tablets and the drug powder exhibited rapid dissolution compared to matrices. CONCLUSION: Based upon our results, it appears that the terfenadine HPMC matrix provides reliable sustained characteristics from RELEASE rate point of view.

The aim of this study is to formulate a novel ophthalmic nanosuspension (ONS), an alternative carrier system to traditional colloidal carriers for CONTROLLED RELEASE (CR) of acyclovir (ACV). In the present study, ONS is employed to avoid some of major disadvantages of colloidal carriers systems such as instability in cul de sac and short half life by increasing efficiency of drug encapsulation as well as by CR. A quassi-emulsion solvent evaporation method was used to prepare ACV loaded Eudragit RS 100 ONS with the aim of improved ocular bioavailability and distribution. Five different formulations were prepared and evaluated for pH of ONS, particle size, entrapment efficiency, differential scanning calorimetry (DSC), in vitro RELEASE profile, in vivo RELEASE studies and stability studies. An average size range of 100 to 300 nm in diameter was obtained and encapsulation efficiency up to 95.0% was observed for all the formulations. Cumulative percent drug RELEASEd for all formulations after 24 h was between 79.28 to 95% indicating effective CR property of ONS. The RELEASE profile revealed from best formulation followed Non-Fickian diffusion mechanism. In vivo studies showed that ACV concentration in aqueous humor at 8 h was 82.83, 77.49 and 34.15 mg/ml. Stability studies showed a maximum drug content and almost similar in vitro RELEASE compared to the initial data found for the sample stored at 4°C. Overall, the study also revealed that ONS was capable of releasing the drug for a prolonged period of time and increased bioavailability.

Context: Biocompatible polymers are potentially effective for dental infections as delivery carriers of disinfectants or antibiotics into the root canal system (RCS). This study aimed to review polymeric microspheres enabling a CONTROLLED RELEASE of endodontic medicaments.Evidence Acquisition: A literature search was carried out in the PubMed database (May 2013) using the following keywords: “poly lactic-co-glycolic acid or PLGA”, “polymer microplate”, “encapsulate”, “drug delivery”, “CONTROLLED RELEASE”, “antibiotic”, “gentamycin”, and “amoxicillin”. We intended to find articles on the application of polymer microparticles for delivery and RELEASE of drugs in dental infections or articles discussing factors affecting the properties of these materials.Results: Seventeen articles were found evaluating the CONTROLLED RELEASE of the drugs for dental purposes; out of them, in 5 in vitro studies, polymer microspheres had been produced for root canal disinfection. Seven articles had investigated the properties of polymer microspheres and the factors influencing drug RELEASE by them.Conclusions: Drug-loaded polymer microspheres may be used successfully as delivery carriers for CONTROLLED RELEASE of antibiotics into the root canal system. The efficacy and success rate of this method must be tested in animal models and then clinical trials.

Despite the huge work concerning the applicability of polymeric hydrogels in the field of drug RELEASE, it is still a promising and interesting area for more improvements and trials for preparing newly designed drug delivery systems. In this study, acrylamide and hydroxyl ethyl methacrylate (HEMA) copolymer hydrogels were prepared with the aid of gamma radiation, and the P(AAM/HEMA) nanocomposite hydrogels were obtained by in situ absorption and reduction method of iron salts and silver nitrates (AgNO3) to form P(AAM/HEMA)-Fe3O4 and P(AAM/HEMA)-Ag nanocomposites. The prepared hydrogels and the formed nanoparticles were studied by various techniques, FT-IR, TEM, SEM, and the gel content and swelling behavior were evaluated. FT-IR confirmed the high interaction, which resulted in the successful formation of the AAm/HEMA copolymer hydrogel. TEM provides a good evaluation of the size of the formed Fe3O4 and Ag NPs to be 12 and 8. 5 nm respectively. The prepared hydrogels and nanocomposite hydrogels were examined as drug delivery systems for Ciprofloxacin HCl as a model drug. The results showed that PAM/HEMA-Fe3O4 nanocomposite gave the suitable load and RELEASE behavior towards Ciprofloxacin HCl.

The purpose of the present study was to develop glipizide CONTROLLED RELEASE nanoparticles using alginate and chitosan thorough ionotropic CONTROLLED gelation method. Glipizide is a frequently prescribed second generation sulfonylurea which lowers the blood glucose in type-two diabetics. Quick absorption of the drug from the gastrointestinal tract along with short half- life of elimination makes it a good candidate for CONTROLLED RELEASE formulations. Alginate-chitosan nanoparticles (ACNP) are convenient CONTROLLED delivery systems for glipizide, due to both the RELEASE limiting properties of the system, and the bioadhesive nature of the polymers. In the present study, glipizide loaded alginate-chitosan nanoparticles (GlACNP) were prepared, and the particle characteristics including particle size (PS), zeta potential (ZP), entrapment efficiency (EE%), loading percent (LP), and mean RELEASE time (MRT), as well as the morphology of the nanoparticles, the drug-excipient compatibility, and the RELEASE kinetics along with the drug diffusion mechanism were evaluated. The results suggested that ionotropic CONTROLLED gelation method offers the possibility of preparing the nanoparticles in mild conditions in an aqueous environment, and can lead to the preparation of particles with favorable size, CONTROLLED RELEASE characteristics, and high entrapment efficiency, serving as a convenient delivery system for glipizide. The particle and RELEASE characteristics can be efficiently optimized using the Box-Behnken design. Based on the findings of the present study, it is expected that this novel formulation be a superior therapeutic alternative to the currently available glipizide delivery systems.

Hydroxypropyl starch was synthesized by modified sago starch with hydroxypropylation reaction. Hydroxypropyl starch nanoparticles with mean particle sizes of 110 nm are obtained by CONTROLLED precipitation through the drop-wise addition of dissolved hydroxypropyl starch solution into excess absolute ethanol. Piperine was loaded onto hydroxypropyl starch nanoparticles and native starch nanoparticles via the in-situ nanoprecipitation process. Hydroxypropyl starch nanoparticles exhibited higher piperine loading capacity as compared to native starch nanoparticles with the maximum loading capacity of 0. 46 and 0. 33 mg. mg-1, respectively. Piperine was RELEASE from hydroxypropyl starch nanoparticles in a slow and sustained manner at pH 1. 2 over the period of 24 hours. Whereas piperine was completely RELEASEd from native starch nanoparticles within 16 hours.

Background and the purpose of the study: Lamotrigine is a broad spectrum anticonvulsant drug widely used as mono- or adjunct- therapy in adults and children. The aim of this study was to develop CONTROLLED RELEASE liquid formulation of lamotrigine to improve bioavailability and compliance of pediatric and geriatric epileptic patients.Methods: Multiple (w/o/w) emulsion was prepared using one step emulsification technique. It was evaluated for entrapment efficiency (EE), morphology, zeta potential (ZP), polydispersity index (PI), rheology, thermal property, in vitro drug RELEASE behavior and stability. In vivo studies in albino mice were carried out using maximal electroshock seizure (MES) test and strychnine induced seizure (SIS) pattern test and results were compared with marketed formulation.Results: The EE of the formulations varied from 84.37% to 98.11%. The ZP and PI values of the prepared batches were in the range of +23.46 to +28.07 and 0.256 and 0.365, respectively. Microscopic observation clearly indicated the stability of the emulsions during the storage period. All batches exhibited CONTROLLED in vitro drug RELEASE up to 12 hrs. Batch C11 exhibited significantly longer duration of protection of seizure in mice against MES and exhibited comparable efficacy in SIS as compared to the marketed formulation.Major Conclusion: Multiple emulsion of lamotrigine compared to the marketed tablet showed plasma drug concentration within therapeutic range for longer time and comparable efficacy.