Formulation of novel sustained release rifampicin-loaded solid lipid microparticles based on structured lipid matrices from Moringa oleifera

Abstract

Objectives: To formulate sustained release rifampicin-loaded solid lipid microparticles (SLMs) using structured lipid matrices based on Moringa oil (MO) and Phospholipon 90G (P90G).

Methods: Rifampicin-loaded and unloaded SLMs were formulated by melt homogenization and characterized in terms of particle morphology and size, percentage drug content (PDC), pH stability, stability in simulated gastric fluid (SGF, pH 1.2), minimum inhibitory concentration (MIC) and in vitro release. In vivo release was studied in Wistar rats.

Results: Rifampicin-loaded SLMs had particle size range of 32.50?±?2.10 to 34.0?±?8.40?μm, highest PDC of 87.6% and showed stable pH. SLMs had good sustained release properties with about 77.1% release at 12?h in phosphate buffer (pH 6.8) and 80.3% drug release at 12?h in simulated intestinal fluid (SIF, pH 7.4). SLMs exhibited 48.51% degradation of rifampicin in SGF at 3?h, while rifampicin pure sample had 95.5% degradation. Formulations exhibited MIC range of 0.781 to 1.562, 31.25 to 62.5 and 6.25 to 12.5?μg/ml against Salmonella typhi, Escherichia coli, and Bacillus subtilis respectively and had higher in vivo absorption than the reference rifampicin (p?<?0.05).

Conclusion: Rifampicin-loaded SLMs could be used once daily for the treatment tuberculosis.     

Solid lipid micro-dispersions (SLMs) based on PEGylated solidified reverse micellar solutions (SRMS): a novel carrier system for gentamicin

Abstract

The purpose of this study was to formulate and evaluate novel PEGylated solidified reverse micellar solutions (SRMS)-based solid lipid microparticles (SLMs) for improved delivery of gentamicin. Lipid matrix (SRMS) [consisting of 15% w/w Phospholipon® 90G (P90G) in 35% w/w dika wax (Irvingia gabonensis) was formulated and characterized by differential scanning calorimetry (DSC). SLMs were formulated by melt-emulsification using the SRMS, PEG 4000 and gentamicin (1.0, 2.0, 3.0% w/w), and their physicochemical as well as pharmacokinetic parameters determined. In vitro permeation of gentamicin from the SLMs through artificial membrane (0.22?μm pore size) was carried out using Franz’s cell and phosphate-buffered saline (PBS, pH 7.4) as acceptor medium, while bioevaluation was performed using clinical isolates of Pseudomonas aeruginosa and Staphylococcus aureus. Stable and irregularly-shaped gentamicin-loaded SLMs of size range 34.49?±?2.56 to 53.52?±?3.09?µm were obtained. The SLMs showed sustained drug permeation and exhibited time-dependent and capacity-limited bioactivity. Overall, SLMs containing 2% w/w SRMS, 3% w/w gentamicin and PEG 4000 entrapped the highest amount of drug, gave highest IZD against the test organisms and highest permeation flux (5.239?μg/cm².min) and permeation coefficient (1.781?×?10^?6?cm/min) within 420?min, while pure gentamicin gave the least. Preliminary in vivo pharmacokinetic studies also showed an AUC-₂₄ of 1507?µg/h/ml for the optimized formulation, while that of oral drug solution was 678?µg/h/ml. This showed a 2.2-fold increase in the systemic bioavailability of gentamicin from the optimized formulation. PEGylated SRMS-based SLMs prepared with heterolipid from Irvingia gabonensis would likely offer a reliable delivery system for gentamicin.     

Formulation and evaluation of novel solid lipid microparticles as a sustained release system for the delivery of metformin hydrochloride

Abstract

The low encapsulation efficiency of conventional solid lipid microparticles (SLMs) especially for hydrophilic drugs has remained a challenge to drug formulation experts. This work seeks to address the issue of inefficient delivery of metformin hydrochloride (MTH), a potent hydrophilic oral antihyperglycemic agent, using novel SLMs based on solidified reverse micellar solutions (SRMS) prepared by melt-emulsification using a lipid derived from Capra hircus and Phospholipon® 90H. Characterization based on size, morphology, zeta potential, polydispersity index, encapsulation efficiency (EE%), loading capacity (LC) and time-resolved stability were carried out on the SLMs. The in vitro release of MTH from the SLMs was performed in phosphate buffer (pH 7.4) while the in vivo antidiabetic properties were investigated in alloxan-induced diabetic rats. Stable, spherical and smooth SLMs were obtained. Loading of MTH into the SLMs had no effect on the surface charge of the particles. The SLMs with 1.0%w/w PEG 4000 resulted in significantly (p?<?0.05) higher EE% while those with 2.0%w/w gave the least. The LC values ranged from 20.3 to 29.1 and 14.6 to 24.1 for SLMs containing 500?mg and 250?mg of MTH, respectively. The in vitro release studies revealed significant release of MTH from the SLMs whereas the in vivo antidiabetic studies indicated that novel SLMs containing 500?mg of MTH gave significantly (p?<?0.05) higher glucose reduction than glucophage®. This research has shown that SLMs based on SRMS offer a new and better approach of delivering MTH, thus encouraging further development of this formulation.     

Sustained-release diclofenac potassium-loaded solid lipid microparticle based on solidified reverse micellar solution: in vitro and in vivo evaluation

Objective: To formulate sustained-release diclofenac potassium-loaded solid lipid microparticles (SLMs) based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties.

Methods: SRMS consisting of mixtures of Phospholipon® 90H and Softisan® 154 were used to formulate diclofenac potassium-loaded SLMs. Characterization based on the particle size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties were studied using rats.

Results: Maximum EE% of 95%, 94% and 93% were obtained for SLMs formulated with SRMS 1:1, 2:1 and 1:2, respectively. In vitro release showed about 85–90% drug release at 13?h. Diclofenac potassium-loaded SLMs showed good anti-inflammatory and gastro-protective properties.

Conclusion: Diclofenac potassium-loaded SLMs based on SRMS could be used orally or parenterally under controlled conditions, for once daily administration.     

Optimization and evaluation of pluronic lecithin organogels as a transdermal delivery vehicle for sinomenine

The purpose of the present study was to prepare and optimize sinomenine (SIN) pluronic lecithin organogels system (PLO), and to evaluate the permeability of the optimized PLO in vitro and in vivo. Box–Behnken design was used to optimize the PLO and the optimized formulation was pluronic F127 of 19.61%, lecithin of 3.60% and SIN of 1.27%. The formulation was evaluated its skin permeation and drug deposition both in vitro and in vivo compared with gel. Permeation and deposition studies of PLO were carried out with Franz diffusion cells in vitro and with microdialysis in vivo. In vitro studies, permeation rate (J_ss) of SIN from PLO was 146.55?±?2.93?μg/cm²/h, significantly higher than that of gel (120.39?μg/cm²/h) and the amount of SIN deposited in skin from the PLO was 10.08?±?0.86?μg/cm², significantly larger than that from gel (6.01?±?0.04?μg/cm²). In vivo skin microdialysis studies showed that the maximum concentration (C_max) of SIN from PLO in “permeation study” and “drug-deposition study” were 150.27?±?20.85?μg/ml and 67.95?μg/ml, respectively, both significantly higher than that of SIN from gel (29.66 and 6.73?μg/ml). The results recommend that PLO can be used as an advantageous transdermal delivery vehicle to enhance the permeation and skin deposition of SIN.     

Preparation of novel solid lipid microparticles loaded with gentamicin and its evaluation in vitro and in vivo

Objective: To formulate and evaluate solid-reversed-micellar-solution (SRMS)-based solid lipid microparticles (SLMs) for intramuscular administration of gentamicin.

Methods: SRMS formulated with Phospholipon® 90G and Softisan® 154 were used to prepare gentamicin-loaded SLMs. Characterizations based on size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release of gentamicin from the SLMs was performed in phosphate buffer while in vivo release studies were conducted in rats.

Results: Maximum EE% of 90.0, 91.6 and 83.0% were obtained for SLMs formed with SRMS 1:1, 1:2 and 2:1, respectively. Stable, spherical and smooth SLMs of size range 9.80?±?1.46?µm to 33.30?±?6.42?µm were produced. The release of gentamicin in phosphate buffer varied widely with the lipid contents. Moreover, significant (p?<?0.05) amount of gentamicin was released in vivo from the SLMs.

Conclusion: SRMS-based SLMs would likely offer a reliable means of delivering gentamicin intramuscularly.     

Formulation,in vitro and in vivo evaluation of halofantrine-loaded solid lipid microparticles

Abstract

Context: Formulation, characterization, in vitro and in vivo evaluation of halofantrine-loaded solid lipid microparticles (SLMs).

Objective: The objective of the study was to formulate and evaluate halofantrine-loaded SLMs.

Materials and methods: Formulations of halofantrine-loaded SLMs were prepared by hot homogenization and thereafter lyophilized and characterized using particle size, pH stability, loading capacity (LC) and encapsulation efficiency (EE). In vitro release of halofantrine (Hf) from the optimized SLMs was performed in SIF and SGF. In vivo study using Peter’s Four day suppressive protocol in mice and the mice thereafter subjected to histological studies in kidney and liver.

Results: Results obtained indicated that EE of 76.32% and 61.43% were obtained for the SLMs containing 7% and 3% of Hf respectively. The SLMs loaded with 3% of Hf had the highest yield of 73.33%. Time-dependent pH stability analysis showed little variations in pH ranging from 3.49?±?0.04 to 4.03?±?0.05.

Discussion: The SLMs showed pH-dependent release profile; in SIF (43.5% of the drug for each of H₂ and H₃) compared with SGF (13 and 18% for H₂ and H₃ respectively) after 8?h. The optimized SLMs formulation and Halfan® produced a percentage reduction in parasitemia of 72.96% and 85.71% respectively. The histological studies revealed that the SLMs formulations have no harmful effects on the kidney and liver.

Conclusion: SLMs formulations might be an alternative for patients with parasitemia as there were no harmful effects on vital organs of the mice.     

The effect of resveratrol on pharmacokinetics of aripiprazole in vivo and in vitro

1.?The objective of this study were to investigate the effect of orally administered resveratrol on the pharmacokinetics of aripiprazole (APZ) in rat, and the inhibitory effects of resveratrol on APZ dehydrogenation activity in liver microsomes and human cytochrome P450 3A4 and 2D6.

2.?Twenty-five healthy male Sprague–Dawley rats were randomly divided into five groups: A (control group), B (multiple dose of 200?mg/kg resveratrol), C (multiple dose of 100?mg/kg resveratrol), D (a single dose of 200?mg/kg resveratrol) and E (a single dose of 100?mg/kg resveratrol). A single dose of 3?mg/kg APZ administered orally 30?min after administration of resveratrol. In addition, CYP2D6*1, CYP3A4*1, human and rat liver microsomes were performed to determine the effect of resveratrol on the metabolism of APZ in vitro.

3.?The multiple dose of 200 or 100?mg/kg resveratrol significantly increased the AUC and C_max of APZ. The resveratrol also obviously decreased the CL, but without any significant difference on t_1/2 in vivo. On the other hand, resveratrol showed inhibitory effect on CYP3A4*1, CYP2D6*1, human and rat microsomes, the IC₅₀ of resveratrol was 6.771, 87.87, 45.11 and 35.59?μmol?l^?1, respectively.

4.?Those results indicated more attention should be paid when APZ was administrated combined with resveratrol.     

The in vitro exposure to cypermethrin does not inhibit the proliferative response of peripheral blood mononuclear cells

This study evaluated the effect of in vitro exposure to cypermethrin on peripheral blood mononuclear cells proliferative response, considering reduced peripheral blood mononuclear cells proliferative response observed in individuals occupationally exposed to pyrethroids. Peripheral blood mononuclear cells were obtained from 21 healthy subjects (28.0?±?9.0 years old). The effect of cypermethrin (at 0.5, 1.0 and 5.0?mg/ml) on cell viability was evaluated by flow cytometry using an apoptosis detection kit. Cell proliferation (PI) was evaluated by 5-(and 6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) fluorescence decay using flow cytometry. Cells labeled with CFSE were exposed, in vitro, to cypermethrin (0.5, 1.0, 2.0, 2.5 and 4?μg/ml) and stimulated with phytohemagglutinin (PHA 1.0 or 5.0?μg/ml) for 5?d (37?°C, 5% CO₂). The in vitro treatment of peripheral blood mononuclear cells with cypermethrin did not induce apoptosis or necrosis after 5?d in culture. Stimulation by PHA induced cell proliferation (PI?=?1.29?±?1.09 and 2.01?±?0.62, PHA at 1.0 and 5.0?μg/ml, respectively, mean?±?SD) and in vitro exposure to cypermethrin did not alter cellular proliferative response to PHA (PI?=?1.80?±?0.50, 2.60?±?0.05 and 2.10?±?1.20 for cypermethrin at 1.0, 2.0 and 4.0?μg/ml, respectively, and PHA at 5.0?μg/ml). In vitro treatment of peripheral blood mononuclear cells with cypermethrin, at the doses tested, does not affect cell viability or proliferation. These findings suggest that the reduction of proliferation observed on lymphocytes derived from individuals occupationally exposed to pesticides may be related to other mechanisms than direct action of cypermethrin on lymphocytes.     

Development and evaluation of carboplatin-loaded PCL nanoparticles for intranasal delivery

Context: The study was aimed to develop a polymeric nanoparticle formulation of anticancer drug carboplatin using biodegradable polymer polycaprolactone (PCL). The formulation is intended for intranasal administration to treat glioma anticipating improved brain delivery as nasal route possess direct access to brain and nanoparticles have small size to overcome the mucosal and blood–brain barrier.

Objective: Development and evaluation of carboplatin-PCL nanoparticles for brain delivery by nasal route.

Methodology: Carboplatin-loaded PCL nanoparticles (CPCs) were prepared by double emulsion-solvent evaporation technique and characterized by particle size, zeta potential, entrapment efficiency, scanning electron microscopy and differential scanning calorimetry. The CPCs were assessed for in vitro release kinetics, ex vivo permeation and in situ nasal perfusion. Cytotoxic potential of CPCs in vitro was evaluated on LN229 human glioblastoma cells.

Results and discussion: The optimized formulation of carboplatin-PCL nanoparticle CPC-08 with particle size of 311.6?±?4.7?nm and zeta potential ?16.3?±?3.7?mV exhibited percentage entrapment efficiency of 27.95?±?4.21. In vitro drug release showed initial burst release followed by slow and continues release indicating biphasic pattern. The ex vivo permeation pattern through sheep nasal mucosa also exhibited a similar release pattern as for in vitro release studies. In situ nasal perfusion studies in Wistar rats demonstrate that CPCs show better nasal absorption than carboplatin solution. In vitro cytotoxicity studies on LN229 cells showed an enhancement in cytotoxicity by CPCs compared to carboplatin alone.

Conclusion: CPC-08 effectively improves nasal absorption of carboplatin and can be used for intranasal administration of carboplatin for improved brain delivery.     

Measurement of Drug in Small Particles from Aqueous Nasal Sprays by Andersen Cascade Impactor

Purpose

To determine if cascade impactor (CI) measurement of drug in small particles from aqueous nasal sprays, described in FDA’s 2003 draft Nasal Bioavailability/Bioequivalence Guidance, can be optimized to reduce measurement variability. To examine the influence of flow rate configurations and number of impactor stages on CI deposition and explore the importance of inlet volume.

Methods

A total of eight assemblies and manual vs. automatic actuation were tested for deposition on the sum of all stages of the CI, and for Group 2 total drug mass per the Guidance. Mean deposition and variance about the mean were determined for each assembly.

Results

The path length for a spherical 1?l inlet was too short to allow adequate aerosol formation. Data variance was reduced by a factor of two or more by using an automatic actuator relative to manual actuation. Impactor assembly modification did not improve variance over the standard assembly.

Conclusions

Use of a spherical inlet (≥2?l volume) and automatic actuation are recommended for comparative measurements of drug in small particles arising from aqueous nasal sprays. The standard (8-stage) 28.3?lpm CI flow rate configuration is recommended when using the Andersen Cascade Impactor (ACI), as no other assembly showed a distinct advantage.     

Formulation and optimization of nanoemulsion using antifungal lipid and surfactant for accentuated topical delivery of Amphotericin B

The objective of the study was to develop, optimize and evaluate a nanoemulsion (NE) of Amphotericin B (AmB) using excipients with inherent antifungal activities (Candida albicans and Aspergillus niger) for topical delivery. AmB-loaded NE was prepared using Capmul PG8 (CPG8), labrasol and polyethylene glycol-400 by spontaneous titration method and evaluated for mean particle size, polydispersity index, zeta potential and zone of inhibition (ZOI). NE6 composed of CPG8 (15%w/w), S_mix (24%w/w) and water (61%w/w) was finally selected as optimized NE. AmB-NE6 was studied for improved in vitro release, ex vivo skin permeation and deposition using the Franz diffusion cell across the rat skin followed with drug penetration using confocal laser scanning microscopy (CLSM) as compared to drug solution (DS) and commercial Fungisome^®. The results of in vitro studies exhibited the maximum ZOI value of NE6 as 19.1?±?1.4 and 22.8?±?2.0?mm against A. niger and C. albicans, respectively, along with desired globular size (49.5?±?1.5?nm), zeta potential (?24.59?mV) and spherical morphology. AmB-NE6 revealed slow and sustained release of AmB as compared to DS in buffer solution (pH 7.4). Furthermore, AmB-NE6 elicited the highest flux rate (22.88?±?1.7?μg/cm²/h) as compared to DS (2.7?±?0.02?μg/cm²/h) and Fungisome^® (11.5?±?1.0?μg/cm²/h). Moreover, the enhancement ratio and drug deposition were found to be highest in AmB-NE6 than DS across the stratum corneum barrier. Finally, CLSM results corroborated enhanced penetration of the AmB-NE6 across the skin as compared to Fungisome^® and DS suggesting an efficient, stable and sustained topical delivery.     

Inertial Particle Deposition in a Monkey Nasal Mold Compared with that in Human Nasal Replicas

Information on nasal particle deposition is used in risk assessments for exposure to airborne particulate pollutants and for optimizing the delivery of therapeutic aerosols. Monkeys are commonly used to assess the therapeutic potential of inhaled substances and to a lesser extent the toxicity of inhaled xenobiotics. Yet no reliable measurements of the deposition efficiency of monkey nasal airways for particles >1 μm have been reported to date. The goals of this study were to measure the deposition efficiency (>1 μm) of a replica of monkey nasal airways and to investigate potential differences in nasal deposition between humans and monkeys by comparing results with similar measurements recently reported for human nasal replicas. The monkey nasal replica was an acrylic mold made from a postmortem cast of the nasal airways of a 12-kg, male rhesus monkey. Particle deposition in the monkey nasal mold was measured for monodisperse aerosols between 1 and 10 μm and constant inspiratory flow rates between 2 and 7 lpm. Total deposition efficiency increased from nearly 0 to 100% with increasing particle inertia and was uniquely determined by values of an inertial impaction parameter. The deposition efficiencies of the monkey replica agreed well with those of human nasal replicas when compared according to equivalent Stokes numbers based on minimum cross-sectional area. Results from this study could improve monkey-to-human extrapolation models and interpretations of data from particle toxicity and therapeutic aerosol studies using monkeys.     

In vitro evaluation of potential drug interactions mediated by cytochrome P450 and transporters for luseogliflozin,an SGLT2 inhibitor

1.?We evaluated potential in vitro drug interactions of luseogliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, mediated by CYP inhibition, CYP induction and drug transporters using human liver microsomes, primary hepatocytes and recombinant cells-expressing efflux or uptake transporters, respectively.

2.?Human CYP inhibition studies indicated that luseogliflozin was a weak inhibitor for CYP2C19 with an IC₅₀ value of 58.3?μM, whereas it was not an inhibitor of the other eight major isoforms that were tested. The exposure of primary hepatocytes to luseogliflozin for 72?hrs weakly induced CYP3A4 at a concentration of 10?μM, whereas it did not induce CYP1A2 or CYP2B6 at concentrations of 0.1–10?μM.

3.?An in vitro transport study suggested that luseogliflozin is a substrate for human P-glycoprotein (P-gp), but not for breast cancer resistance protein (BCRP), organic anion transporting polypeptide (OATP) 1B1 and OATP1B3, organic anion transporter (OAT) 1 and OAT3, or organic cation transporter (OCT) 2. Luseogliflozin weakly inhibited OATP1B3 with an IC₅₀ value of 93.1?μM, but those for other transporters are greater than 100?μM.

4.?Based on the therapeutic plasma concentration of the drug, clinically relevant drug interactions are unlikely to occur between luseogliflozin and coadministered drugs mediated by CYPs and/or transporters.     

Multicomponent aerosol particle deposition in a realistic cast of the human upper respiratory tract

Inhalation of aerosols generated by electronic cigarettes leads to deposition of multiple chemical compounds in the human airways. In this work, an experimental method to determine regional deposition of multicomponent aerosols in an in vitro segmented, realistic human lung geometry was developed and applied to two aerosols, i.e. a monodisperse glycerol aerosol and a multicomponent aerosol. The method comprised the following steps: (1) lung cast model preparation, (2) aerosol generation and exposure, (3) extraction of deposited mass, (4) chemical quantification and (5) data processing. The method showed good agreement with literature data for the deposition efficiency when using a monodisperse glycerol aerosol, with a mass median aerodynamic diameter (MMAD) of 2.3?μm and a constant flow rate of 15?L/min. The highest deposition surface density rate was observed in the bifurcation segments, indicating inertial impaction deposition. The experimental method was also applied to the deposition of a nebulized multicomponent aerosol with a MMAD of 0.50?μm and a constant flow rate of 15?L/min. The deposited amounts of glycerol, propylene glycol and nicotine were quantified. The three analyzed compounds showed similar deposition patterns and fractions as for the monodisperse glycerol aerosol, indicating that the compounds most likely deposited as parts of the same droplets. The developed method can be used to determine regional deposition for multicomponent aerosols, provided that the compounds are of low volatility. The generated data can be used to validate aerosol deposition simulations and to gain insight in deposition of electronic cigarette aerosols in human airways.     

Effects of indirubin and isatin on cell viability,mutagenicity, genotoxicity and BAX/ERCC1 gene expression

Context: Indigofera suffruticosa Miller (Fabaceae) and I. truxillensis Kunth produce compounds, such as isatin (ISA) and indirubin (IRN), which possess antitumour properties. Their effects in mammalian cells are still not very well understood.

Objective: We evaluated the activities of ISA and/or IRN on cell viability and apoptosis in vitro, their genotoxic potentials in vitro and in vivo, and the IRN- and ISA-induced expression of ERCC1 or BAX genes.

Materials and methods: HeLa and/or CHO-K1 cell lines were tested (3 or 24?h) in the MTT, Trypan blue exclusion, acridine orange/ethidium bromide, cytokinesis-blocked micronucleus (CBMN) and comet (36, 24 and 72?h) tests after treatment with IRN (0.1 to 200?μM) or ISA (0.5 to 50?μM). Gene expression was measured by RT-qPCR in HeLa cells. Swiss albino mice received IRN (3, 4 or 24?h) by gavage (50, 100 and 150?mg/kg determined from the LD₅₀ – 1?g/kg b.w.) and submitted to comet assay in vivo.

Results: IRN reduced the viability of CHO-K1 (24?h; 5 to 200?μM) and HeLa cells (10 to 200?μM), and was antiproliferative in the CBMN test (CHO-K1: 0.5 to 10?μM; HeLa: 5 and 10?μM). The drug did not induce apoptosis, micronucleus neither altered gene expression. IRN and ISA were genotoxic for HeLa cells (3 and 24?h) at all doses tested. IRN (100 and 150?mg/kg) also induced genotoxicity in vivo (4?h).

Conclusion: IRN and ISA have properties that make them candidates as chemotherapeutics for further pharmacological investigations.     

Validation of Anatomical Models to Study Aerosol Deposition in Human Nasal Cavities

Purpose

Intranasal deposition of aerosols is often studied using in vitro nasal cavity models. However, the relevance of these models to predict in vivo human deposition has not been validated. This study compared in vivo nasal aerosol deposition and in vitro deposition in a human plastinated head model (NC1) and its replica constructed from CT-scan (NC2).

Methods

Two nebulizers (Atomisor Sonique® and Easynose®) were used to administer a 5.6 μm aerosol of ^99mTc-DTPA to seven healthy volunteers and to the nasal models. Aerosol deposition was quantified by γ-scintigraphy in the nasal, upper nasal cavity and maxillary sinus (MS) regions. The distribution of aerosol deposition was determined along three nasal cavity axes (x, y and z).

Results

There was no significant difference regarding aerosol deposition between the volunteers and NC1. Aerosol deposition was significantly lower in NC2 than in volunteers regarding nasal region (p?<?0.05) but was similar for the upper nasal cavity and MS regions. Mean aerosol distribution for NC1 came within the standard deviation (SD) of in vivo distribution, whereas that of NC2 was outside the in vivo SD for x and y axes.

Conclusions

In conclusion, nasal models can be used to predict aerosol deposition produced by nebulizers, but their performance depends on their design.     

Genotoxicity of antiobesity drug orlistat and effect of caffeine intervention: an in vitro study

Context: Obesity is a major global health problem associated with various adverse effects. Pharmacological interventions are often necessary for the management of obesity. Orlistat is an FDA-approved antiobesity drug which is a potent inhibitor of intestinal lipases. Objective: In the current study, orlistat was evaluated for its genotoxic potential in human lymphocyte cells in vitro and was compared with that of another antiobesity drug sibutramine, presently withdrawn from market due its undesirable health effects. Caffeine intake may be an additional burden in people using anorectic drugs, therefore, further work is needed to be carried out to evaluate the possible effects of caffeine on orlistat-induced DNA damage. Materials and methods: Human lymphocytes were exposed to orlistat (250, 500 and 1000?μg/ml), sibutramine (250, 500 and 1000?μg/ml) and caffeine (25, 50, 75, 100, 125 and 150?μg/ml) to assess their genotoxicity by comet assay in vitro. In addition, lymphocytes were co-incubated with caffeine (50, 75 and 100?μg/ml) and a single concentration of orlistat (250?μg/ml). Results: Orlistat and sibutramine were genotoxic at all concentrations tested, sibutramine being more genotoxic. Caffeine was found to be genotoxic at concentrations 125?μg/ml and above. Co-treatment of orlistat with non-genotoxic concentrations (50, 75 and 100?μg/ml) of caffeine lead to a decrease in DNA damage. Discussion and conclusion: Orlistat can induce DNA damage in human lymphocytes in vitro and caffeine was found to reduce orlistat-induced genotoxicity.     

Safety evaluation of an oat grain alkaloid gramine by genotoxicity assays

Gramine is a natural indole alkaloid that has been isolated from different raw plants occurring mainly in Avena sativa, etc. The study was aimed to investigate the possible in vitro antioxidant, in vitro mutagenic, in vitro antimutagenic, and in vivo genotoxic activity of gramine using ferric reducing ability of plasma (FRAP) assay, Metal chelating, Ames bacterial reverse mutation test, and the mouse bone marrow micronucleus assay as well as chromosomal aberration. Four concentrations of gramine viz. 250, 500, 1000, and 2000?μg/mL were evaluated for its antioxidant activity in FRAP Assay and Metal Chelating Test. Four concentrations of gramine (1250?μg/plate, 2500?μg/plate, 5000?μg/plate, and 10?000?μg/plate) were employed in Salmonella typhimurium strains to study the mutagenicity in the presence and absence of standard mutagens, 2-aminofluorene (2-AF), sodium azide (SA), and 2-nitrofluorene (2-NF). Three doses, i.e. 0.1, 0.2, and 0.3?×?the LD₅₀ of gramine (i.e. 50?mg/kg, 100?mg/kg, and 150?mg/kg) were administered orally to either sex of Swiss albino mice for 48?h to study the genotoxic activity in micronucleus assay as well as chromosomal aberration. Gramine showed potent antioxidant activity in both the assay. Gramine at the given dose lacks mutagenicity as well as found to possess antimutagenic efficacy. Interestingly, S9 enzymes increase the antimutagenic activity in a dose-dependent manner. There was no significant increase in the frequency of micronucleated polychromatic erythrocytes (MNPCEs), as well as no significant difference in the percentage of chromosomal aberrations was observed between the gramine groups and the negative groups but percentage of polychromatic erythrocytes (PCEs) is found to be higher in all the gramine groups. These results indicate significant antioxidant, non-mutagenic as well as non-genotoxic activity of gramine in vitro and in vivo in the given doses.     

Testosterone solid lipid microparticles for transdermal drug delivery. Formulation and physicochemical characterization

Purpose: The main objective of the study was to formulate and characterize testosterone (TS) solid lipid microparticles (SLM) to be applied as a transdermal delivery system.

Methods: Testosterone SLMs were formulated using an emulsion melt homogenization method. Various types and concentrations of fatty materials, namely glyceryl monostearate (GM), glyceryl distearate (GD), stearic acid (SA) and glyceryl behanate (GB) were used. The formulations contained 2.5 or 5?mg TS?g^?1. Morphology, particle size, entrapment efficiency (EE), rheological properties and thermal behaviour of the prepared SLM were examined. In vitro release characteristics of TS from various prepared SLM were also evaluated over 24?h using a vertical Franz diffusion cell. In addition, the effect of storage and freeze-drying on particle size and release pattern of TS from the selected formulation was evaluated.

Results: The results indicated that the type of lipid affected the morphology and particle size of SLM. A relatively high drug percentage entrapment efficiency ranging from 80.7–95.7% was obtained. Rheological studies showed plastic flow characteristics of the prepared formulations. DSC examination revealed that TS existed in amorphous form in the prepared SLM. Release studies revealed the following rank order of TS permeation through cellophane membrane after application of various formulations: 5% GM?<?5% GD?<?5% SA?<?5% GB?<?2.5% GM?<?2.5% SA?<?10% GD?<?10% GB. The drug permeation through excised abdomen rat skin after application of 10% GB–2.5?mg TS?g^?1 SLM was lower than that permeated through cellophane membrane. Moreover, SLM containing 10% GB–2.5?mg TS?g^?1 stored at 5°C showed good stability as indicated by the release study and particle size analysis. Trehalose showed high potential as a cryoprotectant during freeze drying of the selected SLM formulation.

Conclusions: The developed TS SLM delivery system seemed to be promising as a TS transdermal delivery system.