The Effect of the Particle Size Reduction on the Biorelevant Solubility and Dissolution of Poorly Soluble Drugs with Different Acid-Base Character.

Particle size reduction is a commonly used process to improve the solubility and the dissolution of drug formulations. The solubility of a drug in the gastrointestinal tract is a crucial parameter, because it can greatly influence the bioavailability. This work provides a comprehensive investigation of the effect of the particle size, pH, biorelevant media and polymers (PVA and PVPK-25) on the solubility and dissolution of drug formulations using three model compounds with different acid-base characteristics (papaverine hydrochloride, furosemide and niflumic acid).

Use of an In Vitro Skin Parallel Artificial Membrane Assay (Skin-PAMPA) as a Screening Tool to Compare Transdermal Permeability of Model Compound 4-Phenylethyl-Resorcinol Dissolved in Different Solvents.

Absorption through the skin of topically applied chemicals is relevant for both formulation development and safety assessment, especially in the early stages of development. However, the supply of human skin is limited, and the traditional in vitro methods are of low throughput. As an alternative, an artificial membrane-based Skin Parallel Artificial Membrane Permeability Assay (Skin-PAMPA) has been developed to mimic the permeability through the stratum corneum.

Transient voltage-activated K currents in central antennal lobe neurons: cell type-specific functional properties.

In this study we analyzed transient voltage-activated K currents () of projection neurons and local interneurons in the antennal lobe of the cockroach The antennal lobe is the first synaptic processing station for olfactory information in insects. Local interneurons are crucial for computing olfactory information and form local synaptic connections exclusively in the antennal lobe, whereas a primary task of the projection neurons is the transfer of preprocessed olfactory information from the antennal lobe to higher order centers in the protocerebrum. The different physiological tasks of these neurons require specialized physiological and morphological neuronal phenotypes.

Properties and physiological function of Ca2+-dependent K+ currents in uniglomerular olfactory projection neurons.

Ca(2+)-activated potassium currents [IK(Ca)] are an important link between the intracellular signaling system and the membrane potential, which shapes intrinsic electrophysiological properties. To better understand the ionic mechanisms that mediate intrinsic firing properties of olfactory uniglomerular projection neurons (uPNs), we used whole cell patch-clamp recordings in an intact adult brain preparation of the male cockroach Periplaneta americana to analyze IK(Ca) In the insect brain, uPNs form the principal pathway from the antennal lobe to the protocerebrum, where centers for multimodal sensory processing and learning are located. In uPNs the activation of IK(Ca) was clearly voltage and Ca(2+) dependent.

Experimental infection of the squirrel (Sciurus vulgaris) and the muskrat (Ondatra zibethica) with Tahyna virus (California group, Bunyaviridae).

Two squirrels aged 16 weeks and three muskrats aged 24 weeks were subcutaneously infected with a dose of 400 SMicLD50 of the extraneurally passaged "236" strain of Tahyna virus. Viremia was detected in one squirrel (48 and 96 hours post infection) and in two muskrats (24 and 48 hours p.i.

Arbovirological survey in Silica plateau area, Roznava District, Czechoslovakia.

The serosurveys conducted in the Silica plateau area of the Slovak karst region revealed the presence of specific neutralizing antibody against tick-borne encephalitis (TBE) virus in 18% of local inhabitants (33 examined, mostly goats and sheep farmers), 54% of goats (26 examined), 18% of sheep (120 examined) and 13% of cattle (60 examined), against Lipovník (LIP) virus in 30% of inhabitants, 88% of goats, 55% of sheep and 45% of cattle, and against Bhanja (BHA) virus in 27% of inhabitants, 46% of goats, 29% of sheep and 23% of cattle. The results of hemagglutination-inhibition tests with TBE and BHA antigens were analogous. A detailed analysis of these serologic data points to a recent enhancement of the circulation of LIP and BHA viruses and to a very low TBE virus activity in this natural focus of arboviral infections.

Prevalence of arbovirus antibodies in sera of animals in Sri Lanka.

The sera of cattle, goats, dogs and crows from the Colombo area were tested for antibodies against seven arboviruses of the families Togaviridae and Bunyaviridae by a plaque-reduction neutralization microtest, using Vero cells and a stable line of pig kidney (PS) cells. The overall percentages of positive sera among the mammals were: Bhanja, 92.5%; Calovo (Batai), 30.

Detection of human Bhanja virus-specific antibodies in Czechoslovakia.

Blood sera from 185 Czechoslovak citizens, residents of South-Moravia (Znojmo district: 107, Breclav district: 13) and East-Slovakia (Roznava district: 65) regions, were examined for the presence of neutralizing antibodies to Bhanja arbovirus, using PS and Vero cell lines, constant dose of virus and serial serum dilutions. Specific antibody titres greater than or equal to 1:10 were detected in the sera of 10 persons (i.e.

Effect of cyclophosphamide on the infection of mice with Tahyna virus.

Juvenile SPF randombred ICR mice were given intraperitoneally (i.p.) a single dose of cyclophosphamide (CPA - 80 mg/kg), and 10(3.

Identification of Tettnang virus ('possible arbovirus') as mouse hepatitis virus.

Virus isolation attempts in specific-pathogen-free suckling mice (strain ICR) yielded 21 virus strains initially shown to be closely related to or identical with Tettnang virus. Subsequent studies showed them, as well as standard strains of Tettnang virus, to be closely related to or identical with mouse hepatitis virus. Tettnang virus is not an arbovirus.

Is Tettnang virus a possible arbovirus?

The paper describes the isolation of 21 identical virus strains during virus isolation experiments in SPF suckling mice strain ICR. The isolated strains were first identified as closely related or identical to Tettnang virus and later as closely related to mouse hepatitis virus. Tettnang virus seems not to be an arbovirus.

A proposal for the evaluation of vertebrates as to their role in the circulation of arboviruses.

The authors present a proposal for the classification of vertebrates as hosts or hosts-amplifiers of arboviruses from an ecological point of view.

Experimental transmission of Tahyna virus (California group) to wild rabbits (Oryctolagus cuniculus) by mosquitoes.

Two wild rabbits (Oryctolagus cuniculus) were subcutaneously infected with a dose of 2.6 dex. i.

Experimental infection of Putorius eversmanni polecats and Martes foina martens with Tahyna virus.

Three Putorius eversmanni pole-cats and two Martes foina martens aged about 9 months were subcutaneously infected with about 260 suckling mouse LD50 of the extraneurally passaged "236" strain of Tahyna virus (California group, genus Bunyavirus). Viraemia with maximal titres of 1.32 (pole-cats) and 1.

Isolation of Bhanja virus from ticks of the genus Haemaphysalis in southeast Bulgaria and presence of antibodies in pastured sheep.

Bhanja virus was isolated from ticks of the genus Haemaphysalis (H. punctata and H. sulcata) collected from sheep pastured in the surroundings of Akhtopol in southeast Bulgaria, and simultaneously blood sera of 58 sheep were investigated in plaque-reduction neutralization test with B lranja arbovirus.

Virological examination of mosquito larvae from southern Moravia.

254 pools of 4,115 mosquito larvae belonging to nine species were examined by isolation experiments. The larvae were collected in breeding places in an inundated forest--a natural focus of Tahyna virus, in April, June and July 1974 and 1975. Tahyna virus was isolated from one pool of 10 Culiseta annulata larvae collected in July 1974.