Preclinical Assessment of Steroidal Nanostructured Lipid Carriers Based Gels for Atopic Dermatitis: Optimization and Product Development.

BACKGROUND: Betamethasone Valerate (BV) is a potent topical corticosteroid. Preparation of nanostructured lipid carriers (NLC) involves process parameters optimization and formulations were developed. It is available in several conventional formulations like creams and ointments which have well-known problems of frequent dosing and consequently additional side effects. The aim is to ascertain the probability of NLC as an exclusive carrier for betamethasone valerate topical application with regard to release modulation and improved therapeutic effect. METHOD: Preparation of BVNLC formulations involves rigorous broad range optimization of process parameters viz. selection of lipids, surfactants, formulation technique, stirring time, stirring speed and homogenization cycles. Accordingly, optimized parameters were selected and formulation table was developed. Characterizations of developed NLC comprise particle shape, size, zeta potential, percent drug entrapment, in vitro drug release studies. The optimized NLC formulation was gelled and evaluated for ex vivo permeation studies and preclinical anti-inflammatory testing. RESULTS: The permeation studies revealed that enhancement ratio of BVNLC based gel was 2.59 folds higher as compared to plain BV gel. Release models indicated anomalous (non-fickian) diffusion viz. drug release is controlled by more than one process i.e. superposition of both phenomenon, the diffusion controlled as well as swelling controlled release. Preclinical studies indicated a significant (P < 0.05) extended anti-inflammatory effect and 16.5% inhibition compared to plain gel. CONCLUSION: The outcome of entire characterization advocates that the developed formulation is efficient as once a day dosing in therapy of atopic dermatitis.

Modificar en el Petitorio Farmacológico de ESSALUD la unidad de manejo del producto lípidos / Modify in the Pharmacological Request of ESSALUD the product handling unit lipids

Resolución de Instituto de Evaluación de Tecnologías en Salud e Invstigación Número 30 -IETSI-ESSALUD-2016. Vista: La carta Número 272-DETS-IETSI-ESSALUD-2016, el Informe Número 110-S Modificar en el Petitorio Farmacológico de ESSALUD, el siguiente producto farmacéutico: Codigo: 011050115 - Denominación Según DCI: Lipidos - Especificaciones Tecnicas: 20% x 250 mL a 500 mL (apto para mezclas con lípidos incorporados) - Unidad de Manejo: cm³ - Restricción de Uso: 1,7. Disponer que la Dirección de Evaluación de Tecnologías Sanitarias del Instituto de Evaluación de Tecnología en Salud e Investigación haga de conocimiento a todos los órganos desconcentrados, órganos prestadores nacionales, establecimientos de salud y demás órganos que correspondan, la presente Resolución. Disponer que la Dirección de Evaluación de Tecnologías Sanitarias del Instituto de Evaluación de Tecnología en Salud e Investigación coordine con la Gerencia Central de Tecnologías de Información y Comunicaciones, la publicación de lo dispuesto en la presente resolución, en la página Web de ESSALUD.

In Vitro and Ex Vivo Evaluations of Lipid Anti-Cancer Nanoformulations: Insights and Assessment of Bioavailability Enhancement.

Lipid-based nanoformulations have been extensively investigated for improving oral efficacy of plethora of drugs. Chemotherapeutic agents remain a preferred option for effective management of cancer; however, most chemotherapeutic agents suffer from limitation of poor oral bioavailability that is associated with their physicochemical properties. Drug delivery via lipid-based nanosystems possesses strong rational and potential for improving oral bioavailability of such anti-cancer molecules through various mechanisms, viz. improving their gut solubilisation owing to micellization, improving mucosal permeation, improving lymphatic uptake, inhibiting intestinal metabolism and/or inhibiting P-glycoprotein efflux of molecules in the gastrointestinal tract. Various in vitro characterization techniques have been reported in literature that aid in getting insights into mechanisms of lipid-based nanodevices in improving oral efficacy of anti-cancer drugs. The review focuses on different characterization techniques that can be employed for evaluation of lipid-based nanosystems and their role in effective anti-cancer drug delivery.

Quantitative and Mechanistic Assessment of Model Lipophilic Drugs in Micellar Solutions in the Transport Kinetics Across MDR1-MDCK Cell Monolayers.

An approach to characterizing P-glycoprotein (Pgp) interaction potential for sparingly water-soluble compounds was developed using bidirectional transport kinetics in MDR1-MDCK cell monolayers. Paclitaxel, solubilized in a dilute polysorbate 80 (PS80) micellar solution, was used as a practical example. Although the passage of paclitaxel across the cell monolayer was initially governed by the thermodynamic activity of the micelle-solubilized drug solution, Pgp inhibition was sustained by the thermodynamic activity (i.e., critical micelle concentration) of the PS80 micellar solution bathing the apical (ap) membrane. The mechanistic understanding of the experimental strategies and treatment of data was supported by a biophysical model expressed in the form of transport events occurring at the ap and basolateral (bl) membranes in series whereas the vectorial directions of the transcellular kinetics were accommodated. The derived equations permitted the stepwise quantitative delineation of the Pgp efflux activity (inhibited and uninhibited by PS80) and the passive permeability coefficient of the ap membrane, the passive permeability at the bl membrane and, finally, the distinct coupling of these with efflux pump activity to identify the rate-determining steps and mechanisms. The Jmax/KM(∗) for paclitaxel was in the order of 10(-4) cm/s and the ap- and bl-membrane passive permeability coefficients were asymmetric, with bl-membrane permeability significantly greater than ap.

Surface-modified Epirubicin-HCl liposomes and its in vitro assessment in breast cancer cell-line: MCF-7.

BACKGROUND: Epirubicin-HCl is highly efficient for breast cancer management at a concentration of 60-90 mg/m(2). However, its application is limited due to cumulative dose-dependent cardio-toxicity. PURPOSE: The main aim of this study was to formulate breast cancer-targeted liposomal carrier by surface conjugation of transferrin to minimize cardio-toxicity of drug along with improved pharmacokinetic profile. METHOD: Liposomes were formulated by ethanol injection method using HSPC, cholesterol and DSPG and later loaded with drug by the ammonium sulfate gradient method. The formulation was characterized for physicochemical properties like size, zeta potential, entrapment efficiency, TEM; in vitro tests like electro-flocculation, hemolysis and drug release; cell line study (MCF-7 cells); in vivo studies including LD50 determination, pharmacokinetic analysis, myocardial toxicity determination and stability. RESULTS AND DISCUSSION: Optimized formulation had molar ratio of 60:30:8:2 (HSPC:Chol:DSPG:mPEG-DSPE) with entrapment efficiency ∼83%, particle size below 200 nm and zeta potential about -20 mV. In vitro studies proved non-interfering property and drug release character of formulation while cell line studies demonstrated improvement in cell uptake and thereby increased cytotoxicity of targeted formulation. The IC50 value obtained for epirubicin solution, non-targeted and targeted liposomes was 0.675, 0.532 and 0.192 µg/ml, respectively. Furthermore, in vivo tests validated safety and distribution profile of prepared formulations. CONCLUSION: Apt properties of prepared Epirubicin-HCl liposomal formulation warrant its clinical application in breast cancer treatment after further studies.

Assessment of the cellular internalization of thermolytic phosphorothioate DNA oligonucleotide prodrugs.

The bioactivity of a CpG-containing phosphorothioate DNA oligonucleotide with thermolytic 2-(N-formyl-N-methylamino)ethyl (fma) thiophosphate groups in mice led us to investigate the parameters affecting the internalization of these thermosensitive DNA prodrugs in various cell lines. Flow cytometry and confocal microscopy analyses indicate that 5'-fluoresceinated fma-phosphorothioate DNA sequences are poorly internalized in Vero, HeLa and GC-2 cells. However, when four fma-thiophosphate groups of a 15-nucleotide long oligothymidylate prodrug are replaced with 3-(N,N-dimethylamino)prop-1-yl thiophosphate functions, internalization of the positively charged prodrug, under physiological conditions, increased fourfold in HeLa and 40-fold in Vero or GC-2 cells. No cytotoxic effects are observed in Vero cells even at an extracellular prodrug concentration of 50 µM over a period of 72 h. Confocal microscopy studies show that internalization of the positively charged oligothymidylate prodrug in Vero cells is time-dependent with early trafficking of the DNA sequence through endosomal vesicles and, eventually, to the nucleus of the cells. Thus, the incorporation of four 3-(N,N-dimethylamino)prop-1-yl thiophosphate groups into thermosentive fma-phosphorothioate DNA prodrugs is an attractive strategy for efficient cellular internalization of these nucleic acid-based drugs for potential therapeutic indications.

New in vitro dermal absorption database and the prediction of dermal absorption under finite conditions for risk assessment purposes.

Most QSARs for dermal absorption predict the permeability coefficient, K(p), of a molecule, which is valid for infinite dose conditions. In practice, dermal exposure mostly occurs under finite dose conditions. Therefore, a simple model to predict finite dose dermal absorption from infinite dose data (K(p) and lag time) and the stratum corneum/water partition coefficient (K(SC,W)) was developed. To test the model, a series of in vitro dermal absorption experiments was performed under both infinite and finite dose conditions using acetic acid, benzoic acid, bis(2-ethylhexyl)phthalate, butoxyethanol, cortisone, decanol, diazinone, 2,4-dichlorophenol, ethacrynic acid, linolenic acid, octylparaben, oleic acid, propylparaben, salicylic acid and testosterone. For six substances, the predicted relative dermal absorption was not statistically different from the measured value. For all other substances, measured absorption was overpredicted by the model, but most of the overpredictions were still below the European default absorption value. In conclusion, our finite dose prediction model provides a useful and cost-effective estimate of dermal absorption, to be used in risk assessment for non-volatile substances dissolved in water at non-irritating concentrations.

An optical and microPET assessment of thermally-sensitive liposome biodistribution in the Met-1 tumor model: Importance of formulation.

The design of delivery vehicles that are stable in circulation but can be activated by exogenous energy sources is challenging. Our goals are to validate new imaging methods for the assessment of particle stability, to engineer stable and activatable particles and to assess accumulation of a hydrophilic model drug in an orthotopic tumor. Here, liposomes were injected into the tail vein of FVB mice containing bilateral Met-1 tumors and imaged in vivo using microPET and optical imaging techniques. Cryo-electron microscopy was applied to assess particle shape prior to injection, ex vivo fluorescence images of dissected tissues were acquired, excised tissue was further processed with a cell-digest preparation and assayed for fluorescence. We find that for a stable particle, in vivo tumor images of a hydrophilic model drug were highly correlated with PET images of the particle shell and ex vivo fluorescence images of processed tissue, R(2)=0.95 and R(2)=0.99 respectively. We demonstrate that the accumulation of a hydrophilic model drug is increased by up to 177 fold by liposomal encapsulation, as compared to accumulation of the drug at 24 hours.

Prostaglandin analog treatment of glaucoma and ocular hypertension.

OBJECTIVE: To review available data related to the use of prostaglandin analogs (bimatoprost, latanoprost, travoprost, unoprostone) in the management of ocular hypertension and open-angle glaucoma. DATA SOURCES: Primary and review articles were identified from a MEDLINE search (1966-May 2001) and requested information from product manufacturers. STUDY SELECTION AND DATA EXTRACTION: All available information, including that published in articles and abstracts, which was deemed relevant was included in this review. Limited data have been published to date. DATA SYNTHESIS: The prostaglandin analogs appear to be effective, well-tolerated agents for the reduction of intraocular pressure (IOP) in patients with primary open-angle glaucoma and ocular hypertension. This drug class offers an alternative for patients who do not achieve control with another topical antiglaucoma agent or for those with a contraindication to first-line therapy with beta-adrenergic antagonists. Based on preliminary clinical data, bimatoprost, latanoprost, and travoprost appear to be at least as effective as timolol, while the effectiveness of unoprostone is similar or slightly less. Prostaglandin analogs may be used in conjunction with other antiglaucoma medications, although further studies must establish the optimal combination. Whether clinical experience will yield outcomes in favor of one of the prostaglandin analogs remains to be determined. Patients should be educated on adverse events associated with prostaglandin analogs, particularly the potential for changes in the pigmentation of the iris and eyelashes. CONCLUSIONS: Bimatoprost, latanoprost, and travoprost appear to be equivalent to the current standard of therapy in the topical treatment of elevated IOP. Further clinical data published in article versus abstract format is required to better assess potential differences among these 3 agents.

In vitro assessment of oral lipid based formulations.

In recent years there has been an increase in interest in the utility of lipid based delivery systems, at least in part as a result of the effective development of lipid based products such as Sandimmun Neoral (cyclosporin), Norvir (ritonavir) and Fortovase (saquinavir). The development pathway for lipid based formulations, however, is still largely empirical, and in vitro models that are predictive of oral bioavailability enhancement are lacking. The use of modified dissolution media, reflecting the bile salt and phospholipid levels in the intestine, has met with some success in terms of the ability to predict the bioavailability of poorly water soluble drugs and the potential bioavailability enhancing effects of food. These approaches, however, do not have the flexibility or complexity to deal with the interactions inherent in the digestion, dispersion and solubilisation of a lipid based formulation and the coincident dissolution profile of a co-administered drug. In this review, the utility of modified dissolution media to predict the impact of food on the absorption of poorly water soluble, lipophilic drugs, is explored. These dissolution based systems are subsequently contrasted with the use of lipid digestion models which have found increasing application in assessment of the interaction of digestible dose forms with the gastrointestinal milieu.

Alternative blood conduits: assessment of whether the porosity of synthetic prostheses is the key to long-term biofunctionality.

The paper examines the effects of water permeability on solid particle (platelet) adhesion and lipid transport through the wall of a blood conduit. Also tested is the capacity of external supports to reduce lipid infiltration into venous grafts. The results indicate that water permeability not only facilitates particle adhesion, but also affects the spatial distribution of the adhesion. The presence of filtration flow leads to a concentration polarisation of atherogenic lipids at the blood/wall interface, with increased lipid concentration from the bulk value towards the interface, thus enhancing the drive potential for lipid infiltration into the vessel wall. An external support to a venous graft guards against excessive distention and significantly reduces lipid infiltration into the venous wall. These results strongly suggest that too high a water permeability or porosity can lead to the late failure of arterial grafting by affecting blood cell interaction with the graft and lipid infiltration into the wall. Therefore the pore structure of an arterial prosthesis is crucial to its long-term biofunctionality. Ideally, a synthetic prosthesis should display pores of adequate size and a structural network that promotes tissue ingrowth, while maintaining water porosity at a physiological level.

Protein turnover and energy expenditure increase during exogenous nutrient availability in sickle cell disease.

In the present study, energy expenditure (EE) and rates of whole-body protein, glucose, and lipid metabolism were assessed in 8 African American sickle cell disease (SCD) patients and in 6 healthy African American control subjects during the infusion of amino acids, glucose, and lipid. Whole-body protein, glucose, and lipid kinetics were estimated by using L-[1-(13)C]leucine, D-[6,6-(2)H2]glucose, and [(2)H5]glycerol, respectively. After a 2-h tracer equilibration period and a 0.5-h basal period, nutrients were administered intravenously for 3 h with 16% of the energy as protein, 52% as carbohydrate, and 32% as fat. Breath and blood were collected during the last 30 min of nutrient infusion and EE was measured by indirect calorimetry. EE was 14% greater (P < or = 0.05) in SCD patients [145.0 +/- 3.5 kJ x kg fat-free mass (FFM)(-1) x d(-1)] than in control subjects (126.8 +/- 3.8 kJ x kg FFM(-1) x d(-1)). Whole-body protein breakdown (4.4 +/- 0.4 compared with 3.1 +/- 0.1 mg x kg FFM(-1) x min(-1), P < or = 0.05) and protein synthesis (4.6 +/- 0.4 compared with 3.2 +/- 0.1 g x kg FFM(-1) x min(-1), P < or = 0.05) were 42% and 44% greater, respectively, in the SCD patients than in control subjects, but whole-body amino acid oxidation (0.90 +/- 0.05 compared with 1.03 +/- 0.09 mg x kg FFM(-1) x min(-1)) was not significantly different between the 2 groups. Whole-body glucose and lipid kinetics did not differ significantly between the groups. EE increased in SCD patients during exogenous nutrient availability, and the additional energy required for the accelerated rates of whole-body protein breakdown and synthesis made a significant contribution to the increase in EE. These metabolic aberrations may increase the dietary energy and protein requirements of SCD patients.