In vitro/in vivo evaluation of gamma-aminobutyric acid-loadedN,N-dimethylacrylamide-based pegylated polymeric nanoparticles for brain delivery to treat epilepsy.

Objectives of this study were the delivery of gamma aminobutyric acid (GABA) into the brain by means of developing brain targeted, nanosized, non-toxic and biocompatible polymeric nanoparticles, and investigating their effectiveness in epilepsy. For this purpose, GABA conjugated N,N-dimethylacrylamide-based pegylated nanoparticles were designed and characterised for particle size, zeta potential, pH, morphology, DSC, XRD, FTIR, GABA quantification and in vitro release. Formulations showed smaller particle size, cationic zeta potential characteristic, possible GABA polymeric matrix interaction and prolonged release pattern. Brain responses were examined using epileptic rats. Both formulations prepared were found to increase latency of seizure, decrease ending time of convulsion, duration of severe convulsion and mortality rate significantly compared with GABA solution. When GABA concentration was measured in Stratum corsatum, there was no statistical difference between GABA solution and formulations. All findings suggested enhancement in all phases of seizures indicating efficient delivery of GABA into the brain via formulations.

Chitosan nanoparticles for ocular delivery of cyclosporine A.

In the present study, cyclosporine A (CsA) was successfully incorporated into cationic chitosan nanoparticles by spray-drying method aiming ocular application. Physicochemical characterisation of particles was performed in detail. Among the particles prepared using three types of chitosan with different molecular weights, particles containing chitosan with medium molecular weight was selected for in vivo studies. Selection was dependent on higher incorporation and encapsulation efficiencies of CsA and also better release characteristic in simulated tear fluid. Sheep were used in in vivo studies. Biological samples were collected at predetermined time intervals and were analysed by enzyme immune assay. CsA could be detected in both aqueous and vitreous humour samples for the duration of 72 h. In vivo release profiles indicated prolonged release of active agent from positively charged chitosan formulations. This may be attributed to enhanced residence time at the corneal and conjunctival surfaces.

Moxifloxacin Hydrochloride-Loaded Eudragit® RL 100 and Kollidon® SR Based Nanoparticles: Formulation, In vitro Characterization and Cytotoxicity.

BACKGROUND: Considering the low ocular bioavailability of conventional formulations used for ocular bacterial infection treatment, there is a need to design efficient novel drug delivery systems that may enhance precorneal retention time and corneal permeability. AIM AND OBJECTIVE: The current research focuses on developing nanosized and non-toxic Eudragit® RL 100 and Kollidon® SR nanoparticles loaded with moxifloxacin hydrochloride (MOX) for its prolonged release to be promising for effective ocular delivery. METHODS: In this study, MOX incorporation was carried out by spray drying method aiming ocular delivery. In vitro characteristics were evaluated in detail with different methods. RESULTS: MOX was successfully incorporated into Eudragit® RL 100 and Kollidon® SR polymeric nanoparticles by a spray-drying process. Particle size, zeta potential, entrapment efficiency, particle morphology, thermal, FTIR, NMR analyses and MOX quantification using HPLC method were carried out to evaluate the nanoparticles prepared. MOX loaded nanoparticles demonstrated nanosized and spherical shape while in vitro release studies demonstrated modified-release pattern, which followed the Korsmeyer-Peppas kinetic model. Following the successful incorporation of MOX into the nanoparticles, the formulation (MOX: Eudragit® RL 100, 1:5) (ERL-MOX 2) was selected for further studies because of its better characteristics like cationic zeta potential, smaller particle size, narrow size distribution and more uniform prolonged release pattern. Moreover, ERLMOX 2 formulation remained stable for 3 months and demonstrated higher cell viability values for MOX. CONCLUSION: In vitro characterization analyses showed that non-toxic, nano-sized and cationic ERL-MOX 2 formulation has the potential of enhancing ocular bioavailability.

Cyclosporine-A incorporated cationic solid lipid nanoparticles for ocular delivery.

In the present study, Cyclosporine A (CsA) was successfully incorporated into cationic solid lipid nanoparticles (SLN) for ocular application. Physicochemical characterizations of SLNs were analysed in detail during the storage period of 6 months. Due to the better characteristics like smaller particle size (248.00 +/- 0.33 nm) with narrow size distribution (PI = 0.25 +/- 0.00), high zeta potential (50.30 +/- 0.78 mV) and more stable lipid structure, Dynasan 116 structured FD4 (0.1% CsA) formulation was chosen for in vivo studies. Sheep were used in in vivo studies and 200 microL of formulation was applied to sheep' eyes (n = 6) under veterinarian supervision. Samples were collected at pre-determined time intervals and were analysed by enzyme immune assay (EIA). CsA could be detected in both aqueous and vitreous humour samples for 48 h showing the ocular penetration of formulation. Release profiles were not decreased during 48 h indicating controlled and prolonged release of active agent from positively charged SLN formulations due to increased residence time in eyes. Similarities in CsA concentration data showed that inter-individual variance did not influence the ocular penetration of CsA when formulated as SLN.

Formulation and in-vivo evaluation of a cosmetic multiple emulsion containing vitamin C and wheat protein.

The purpose of the study was to see the effect of two antiaging agents in one stable multiple emulsion prepared using natural oil. Vitamin C, which is a very unstable ingredient and is decomposed in the presence of oxygen, active as an antioxidant, was entrapped in the inner aqueous phase of w/o/w multiple emulsion. In this way, slow release can be expected and the effect of vitamin C can be increased since it is protected from the external environment by entrapping it in the internal phase. The other ingredient which is a product of wheat proteins was also used as an antiaging agent in the oily phase. Both of the ingredients increase the synthesis of collagen fibers in the dermis. Therefore, a synergystic effect can be produced by using the two ingredients in one formulation. In this study, multiple emulsions were prepared by the two-step method. Basic formulation containing no active material and a stable formulation containing vitamin C in the internal aqueous phase and wheat protein in the oily phase were prepared. The oil used was macadamia nut oil since it contains a high quantity of palmitoleic acid which is the natural ingredient of the young skin. Basic formulation as well as the active formulation after confirming their stabilities, were applied to the cheeks of 11 human volunteers for four weeks. Different parameters of the skin were monitored every week to see any effect produced by these emulsions. The data obtained was evaluated statistically. It was found that the active formulation as well as base increased the moisture of the skin as verified by statistical tests. However, there were no significant variations in other parameters like skin sebum, pH, elasticity, melanin and erythema, concerning the two formulations.

Preparation of prolonged release clarithromycin microparticles for oral use and their in vitro evaluation.

Prolonged release microparticles of clarithromycin (CL) were prepared using Eudragit RL 100 and RS 100 by spray-drying and casting-drying techniques. For the characterization of those microparticles, preparation yield, particle size distribution, X-ray diffraction, thermal behavior, active agent content and in vitro dissolution from the microparticles were performed. HPLC was used for the assay of clarithromycin and the assay method was validated. All the formulations obtained showed prolonged release when compared to pure clarithromycin. Microparticles prepared by spray-drying method had a slower release compared to those of casting-drying method. Spray-drying method seems to be a more suitable method to prepare microparticles for prolongation in release.

Preparation and in vitro evaluation of vaginal formulations including siRNA and paclitaxel-loaded SLNs for cervical cancer.

Cervical cancer is one of the most life threatening types of cancer among women and is generally resistant to chemotherapy. The objective of this study was to prepare a vaginal suppository containing a chemotherapeutic agent and a genetic material that can be applied locally for cervical cancer. Paclitaxel was selected as the chemotherapeutic agent and siRNA which inhibits BCL-2 oncogene was selected as the genetic material. Bcl-2 siRNA, paclitaxel and paclitaxel/Bcl-2 siRNA combination were incorporated into solid lipid nanoparticles (SLNs) and were dispersed separately in vaginal suppositories prepared with PEG 6000. Physicochemical properties of SLNs, their cytotoxicities on HeLa cell lines and also the effect of SLNs on the total protein amount of the cells were examined followed by the investigation of release rates of the active materials from the SLNs prepared. Average diameters of all SLNs prepared were below 180nm with a positive zeta potential value between +22.20 and +48.16mV at the pH range of 4.2 and 7.4. The release of Bcl-2 siRNA from SLNs incorporated Bcl-2 siRNA and the release of paclitaxel (PTX) from PTX incorporated SLNs were completed within 12h and 36h. SLNs incorporating Bcl-2 siRNA and paclitaxel/Bcl-2 siRNA were found to be more toxic when compared to paclitaxel incorporated SLN and placebo SLN. The disintegration of the vaginal suppositories as well as the release of the SLNs was completed within 2 h. This study indicates that vaginal suppository containing SLNs can bring the advantages of the simultaneous delivery of paclitaxel and siRNA via vaginal route with no help from professionals.

Gamma-aminobutyric acid loaded halloysite nanotubes and in vitro-in vivo evaluation for brain delivery.

Gamma-aminobutyric acid (GABA) is a key neurotransmitter where it usually inhibits impulse transmission. GABA release blockage or postsynaptic reaction were determined to provoke epileptic convulsions. The aim of the present study was the development of brain-targeted, nanosized, nontoxic, biocompatible, highly specific formulations. Incorporation of GABA into halloysite nanotubes (HNT) was performed using different methods. Particle size, zeta potential and pH measurements, morphological, thermal, XRD, FTIR analyses and GABA quantification by validated HPLC method were used for the characterization of the systems prepared. Release pattern of GABA from the nanotubes was determined using a dialysis membrane. Following successful incorporation of GABA into HNTs for brain delivery, nanotube formulation coded HNT-GABA H1 was selected for in vivo studies. Smaller particle size with narrow size distribution, possible HNT-GABA interaction indicated by thermal, XRD and FTIR analyses and prolonged release were the parameters considered in this selection. Moreover, HNT-GABA H1 remained stable for 3-month storage period and showed higher cell viability values than GABA. Rats were used in in vivo studies and potential of anticonvulsant effect of GABA was determined in the pentylenetetrazole model of seizure. HNT-GABA H1 was found to increase latency of seizure, decrease ending time of the convulsion, duration of severe convulsion and mortality rate significantly compared to pure GABA. After administration of HNT-GABA H1, GABA concentration in Stratum corsatum measured by enzyme immune assay showed that it was not significantly higher than GABA administered alone. These findings suggest that GABA loaded HNTs reduces the duration of all phases of convulsion indicating efficient delivery of GABA to all brain areas to interfere with epileptic mechanism.

Preparation and in vitro evaluation of pyridostigmine bromide microparticles.

Pyridostigmine bromide (PB) is an anticholinesterase agent whose aqueous solubility is high and which has a short elimination half-life. Its dosage rate in the treatment of myastenia gravis is frequent due to the short half-life and it exhibits side effects. Microparticles designed to deliver a pharmaceutical active ingredient efficiently at the minimum dose and also to enhance stability, reduce side effects and modify drug release were prepared in this study using an acrylic polymer (Eudragit) as the vehicle by the spray-drying technique. The drug was either dissolved or dispersed in the polymeric solution and following the preparation of microparticles using different ratios of ingredients, characterization studies including the determination of shape, particle size distribution, amount loaded, release and stability of PB were performed. The results obtained were compared to those of pure PB. Drug release from microparticles could be modified and was found to depend on the shapes of the microparticles. In vitro evaluation results indicate that the frequent dosage and side effects of pure PB may be reduced with the formulation of microparticles.

Development and in vitro/in vivo evaluation of thermo-sensitive in situ gelling systems for ocular allergy

Ocular allergy is one of the most common disorders of the eye surface. Following diagnosis this condition is typically treated with preparations containing antihistamines. However, anatomy of the eye and its natural protective mechanisms create challenges for ocular drug delivery. Rapid elimination of antihistamine substances due to short residency times following application can lead to insufficient treatment of ocular allergies. With this in mind, the aim of this study was to prepare a controlled ocular delivery system to extend the retention time of olopatadine hydrochloride (OLO) and in doing so to reduce the need for frequent application. We developed extended-release ocular in situ gelling systems for which in vivo retention times were determined in sheep following in vitro characterization and cytotoxicity studies. In vivo results were then compared to commercially available Patanol eye drops. the transparent gels formulated using appropriate amounts of polymers and having longer ocular retention times appear to be a viable alternative to commercially available eye drops.

Ocular application of chitosan.

INTRODUCTION: A major problem in ocular therapeutics with classical formulations is the maintenance of an effective drug concentration at the site of action for a long period of time. Enhancement of ocular bioavailability with increased dose penetration and longer retention time at desired sites can be achieved by recent formulations. Chitosan stands out with its unique structural advantageous characteristics for different types of formulations like in situ gelling systems, micro- and nanoparticles, inserts, etc. AREAS COVERED: In this review, the authors focus on ocular therapeutics and the characteristics that make chitosan more acceptable in ocular applications. EXPERT OPINION: Chitosan seems to be one of the most promising polymeric carriers for both hydrophilic and lipophilic drugs for ocular application.

Polymeric cyclosporine-A nanoparticles for ocular application.

In the present study, cyclosporine A (CsA) was incorporated successfully into cationic Eudragit RS 100 nanoparticles (EPNs) aiming ocular application. Physicochemical characterization of the EPNs prepared was performed during the storage period of 6 months. Following in vitro release tests, sheep were used in in vivo studies where 100 microL of formulation was applied to both eyes (n = 6) under veterinarian supervision. Aqueous and vitreous humour samples were collected at predetermined time intervals and analyzed by enzyme immune assay (EIA). In vitro relase studies showed the extended release of the incorporated drug from the nanoparticles. However in vivo results demonstrated the prolonged residence time of CsA in the deeper layers (vitreous humour) of the eye with positively charged EPNs.