Study on process parameters and optimization of microencapsulation based on phase separation.

As surfactants are capable of influencing the droplet formation, our study primarily aims the investigation of the effect of a nonionic surfactant e.g. Polysorbate 80 on the formation of microspheres on the course of vibrating nozzle method with coacervation. The experiments also concern the impact of the different process parameters (e.g. vibration frequency, feed rate and voltage) on the shape and size distribution of microspheres characterized by laser diffraction size determination completed with particle image analysis. The calcium-alginate microspheres were processed using freeze-drying to ensure solid state with better drug carrier capability. Addition of isomalt was advantageous in the formation of freeze-dried microspheres at low alginate concentration, which was explained by micro-CT analysis of the constructed particle structure. The internal three-dimensional network of calcium alginate demonstrated a more cancellous architecture ameliorating the roundness of microparticles.

Developing and advancing dry powder inhalation towards enhanced therapeutics.

Enhanced therapeutics are drug products derived from existing generic drugs that provide additional benefits to the patients and the healthcare system. Enhanced therapeutics are considered to be an important and relatively low risk source of innovation. Pulmonary drug delivery is the major delivery route to treat chronic respiratory diseases and has been proven as a potential delivery route for complex drugs that cannot be delivered orally. Development of dry powder inhalation systems targets the delivery of fine drug particles to the deep lung surface by a combination of drug formulation, primary packaging and a device, whereby each contributes to the overall performance. Various methodologies for the non-clinical and clinical performance testing of orally inhaled products have been proposed and applied with variable success. Regulatory pathways have been developed and applied since. Considerable efforts have been made during the past decade to understand and optimize pulmonary drug delivery including their efficient commercial manufacturing. Pulmonary drug delivery remains an area of future innovation in the effective treatment of pulmonary diseases as well as the systemic delivery of systemically active complex drugs.

New formulation of in situ gelling Metolose-based liquid suppository.

CONTEXT: An in situ gelling liquid suppository is liquid at room temperature but forms a gel at body temperature. In our work, Metolose® SM-4000 (methylcellulose) is studied that basically shows thermal gelation at 68°C (2%, w/w). OBJECTIVE: The objective was to study the potency of different factors (concentration, pH, additives) to change the value of thermal gelation temperature (T (t)) for Metolose® to form an in situ gelling liquid suppository. MATERIALS AND METHODS: We studied the effect of Metolose® concentration, pH, and salts (sodium chloride, potassium chloride, sodium hydrogen carbonate, and sodium monohydrogen phosphate) on T (t) by viscosimetry. To choose the appropriate compound, in vitro drug release was examined. Rectal safety test was performed on rats in vivo after 12-hour application. RESULTS: Increasing the Metolose® concentrations (0.5-4%, w/w), T (t) can be decreased, but it also altered the consistency of gel. pH does not affect the T (t). The water-soluble salts allowed reducing the gelation temperature to 37°C. Sodium monohydrogen phosphate in 4.5% concentration was found to be the most appropriate. The impact of examined factors on in vitro drug release of piroxicam from the in situ-formed gel was characterized according to Fickian diffusion. Metolose® and the chosen salt did not cause any morphological damage on the rectal tissues. DISCUSSION: According to our study, Metolose® has the physical and chemical potential to be used as base for liquid suppositories.

In vitro food-drug interaction study: Which milk component has a decreasing effect on the bioavailability of ciprofloxacin?

The purpose of the present work was developing an in vitro dissolution test to highlight the possible molecular background causing ciprofloxacin (CPFX)-milk interaction. The in vitro dissolution of CPFX from film-coated tablets (Ciprinol) 500mg) was examined at different pH values, simulating certain parts of the gastrointestinal tract, in the presence of water, low-fat milk, casein- or calcium enriched water. In order to determine the amount of dissolved CPFX, solid phase extraction sample preparation followed by high performance liquid chromatography coupled with mass spectrometry was applied. Comparing the dissolution efficiency values in various media, it can be concluded, that casein has a more pronounced effect on the absorbable amount of the antibiotic at each pH value studied, than calcium. In the case of concomitant intake of CPFX film-coated tablet and milk or other dairy products not only the complexation with calcium, but also the adsorption of CPFX on the surface of proteins decreases the absorbable amount of CPFX.

Characterization of liposomal vesicles encapsulating rhodanese for cyanide antagonism.

The major mechanism of removing cyanide from the body is its enzymatic conversion by a sulfurtransferase, e.g. rhodanese, to the less toxic thiocyanate in the presence of a sulfur donor. Earlier results demonstrated that externally administered encapsulated rhodanese significantly enhances the in vivo efficacy of the given sulfur donor. Present studies are focused on liposomal carrier systems encapsulating rhodanese. Physicochemical properties, e.g. membrane rigidity, size distribution, surface potential, osmolarity, and viscosity, were determined for various liposomal lipid compositions and hydrating buffers to establish in vitro stability and in vivo fate. Lipid composition was also optimized to achieve maximum encapsulation efficiency.

Formulation of thermoresponsive and bioadhesive gel for treatment of oesophageal pain and inflammation.

The aim of this study was the formulation and examination of a novel thermoresponsive and bioadhesive, in situ gelling drug delivery system, which can be used in the treatment of oesophageal pain and inflammation. A bioadhesive cellulose derivative (Metolose) 60SH) was used as a thermoresponsive material, because Metolose has thermal gelation properties at certain temperature. The thermal gelation temperature (T(2)) of Metolose 60SH 2 w/w% solution is above body temperature (65-66 degrees C), but by using different methods (Metolose 60SH concentration, auxiliary materials), it can be shifted near to body temperature. The pH alteration between pH=2-10 and the application of different alcohols did not influence the gelation temperature, but using water-soluble salts and changing the concentration of Metolose 60SH solution between 2 and 3 w/w% the thermal gelation point could be decreased. Different NSAIDs were used as model drugs and which had not influence on thermal gelation temperature, but difference in in vitro liberation and penetration can be observed. In vitro adhesion test pointed out that the condition of investigated membrane can change the adhesion. Morphological test of oesophageal tissue showed that investigated materials had no irritative or tissue-damaging effect on the oesophageal mucosa even after 12h.

Liposomal oxytetracycline and doxycycline: studies on enhancement of encapsulation efficiency.

Liposomal encapsulations of oxytetracycline (OTC) and doxycycline (DC) with various lipid compositions and hydrating solutions have been studied in order to develop a new liposomal formulation to treat bacterial infections. Encapsulation efficiencies as a function of pH (pH 4.0-8.0) in ionic (phosphate buffers) and non-ionic (mannitol or glucose) hydrating solutions with various lipid compositions (lecithin or α-L-dipalmitoylphosphatidylcholine, with or without cholesterol) were determined and compared to the character of lipid vesicles. Based on our encapsulation efficiency studies and on the drug stability considerations it can be concluded that for OTC/DC encapsulation the use of non-ionic solutions is the most promising.

Potential application of Metolose in a thermoresponsive transdermal therapeutic system.

The purpose of the present study was to formulate a novel thermoresponsive membrane controlled therapeutic system from Metolose for possible transdermal application. Metolose gel shows thermal gelation property, which can be characterized by two (T(1), T(2)) temperatures. A sharp decrease of viscosity can be measured at T(1), but gelation can be observed at T(2). Different types of Metolose polymers were compared considering their thermoresponsive behaviour. Only thermal gelation was observed in the case of Metolose SM, while Metolose SH showed a sudden decrease of viscosity at T(1). Since this temperature is above the body temperature, so it should be shifted to the skin temperature in case of possible transdermal application. Modulation of thermoresponsibility was followed by rheological method, and the thermoresponsive drug release from Metolose gel was studied by static liberation test. Our results demonstrated that the effect of different salts (NaCl, NaHCO(3), KCl) of various concentrations in Metolose SH gel reduced T(1) to the skin temperature, which enabled enhanced drug release.

Metabolism of moexipril to moexiprilat: determination of in vitro metabolism using HPLC-ES-MS.

Moexipril is a long-acting, non-sulfhydryl angiotensine-converting enzyme inhibitor. It is used for treatment of arterial hypertension. Moexipril is the prodrug, yielding moexiprilat by hydrolysis of an ethyl ester group. Moexiprilat is the metabolite responsible for the pharmacological effect after moexipril administration. Samples of rat and human microsomal preparations exposed to moexipril treatment were analyzed by HPLC using octyl silica stationary phase and isocratic elution. To detect moexipril and moexiprilat the separation was monitored by both ultraviolet and mass specific detection. The rat liver microsomal preparation was more effective to in producing moexiprilat than the similar one derived from human liver cell lines. While additional potential metabolites of moexipril were suggested by computer-modeling, moexiprilat was the sole metabolite detected after microsomal treatment.

The effect of oil as a dietary component on in vitro dissolution of an acid-labile drug.

The non-benzodiazepine-like anxiolytic agent deramiclane fumarate (EGIA-3886) was used to demonstrate that the presence of high oil/fat content in dissolution media serves as a barrier against accelerated drug degradation in acidic media.

Metabolite analysis, isolation and purity assessment using various liquid chromatographic techniques combined with radioactivity detection.

During the discovery of metabolic routes of a drug candidate, radioactively labeled substances are administered. This study reports the multidimensional application of overpressured layer chromatography (OPLC) and high-performance liquid chromatography (HPLC) coupled with online or off-line nondestructive radioactivity detection methods in metabolism studies. Among these methods, digital autoradiography and flow-cell radioactivity detectors (RD) using solid scintillators are used. In this study, the hyphenation of OPLC with RD is reported. The application of the OPLC-RD technique is demonstrated on a metabolism study as well as the multidimensional chromatographic selectivity using normal-phase OPLC for the separation in the first dimension, followed by reversed-phase HPLC-RD, which provides additional selectivity to the separation. Information regarding the identity of radiolabeled metabolites and data obtained from spectroscopic methods could be advantageously used during structure elucidation.

Comparative bioavailability of alpha-methyldopa normal and film tablet formulations after single oral administration in healthy volunteers.

In a single dose, randomized, cross-over study, with one week of wash-out period, the relative bioavailability of Dopegyt tablets containing 250 mg alpha-methyldopa (AMD) and Presinol film tablets with identical active ingredient content was examined in 24 healthy volunteers. Since technologically two completely different preparations (a film-tablet and a non-film-tablet) having significantly different in vitro dissolution were to be compared, both preparations were compared to a third one, AMD solution (Dopegyt solution) with 250 mg/50 ml concentration. Plasma concentrations of the drug were measured for 24 hours post-dose, applying HPLC with fluorometric detection. Pharmacokinetic parameters calculated from individual data (AUC0-infinity, AUC0-t, Cmax, Cmax/AUC0-infinity, t(max)) were evaluated statistically. Wilcoxon's nonparametric test and the four-way variance analysis could not detect any significant difference at the usual a=95% probability level in these pharmacokinetic parameters of the two tablet preparations. For AUC0-infinity at the 90% probability level, the confidence interval was 0.883-1.237 (with an estimated geometric mean of 1.045), for the test/reference ratio of Dopegyt and Presinol tablets, thus the two preparations proved to be bioequivalent. The relative bioavailability of Dopegyt (test preparation) and Presinol (reference preparation) calculated from the AUC0-infinity values was 116.7+/-56.7% that also confirmed bioequivalence. The results of all the applied statistical tests suggest that Dopegyt and Presinol can be considered as bioequivalent preparations.

Determination of deramciclane and N-desmethylderamciclane in human plasma by liquid chromatography-tandem mass spectrometry using off-line robotic sample pretreatment.

A rapid and highly sensitive LC-MS-MS method using deuterium-labelled internal standards was developed and evaluated for the simultaneous determination of deramciclane and its pharmacologically active metabolite (N-desmethylderamciclane). The sample preparation based on liquid-liquid extraction was carried out with an off-line robotic system. Evaluation of this analytical method shows that samples can be assayed with acceptable accuracy and precision in the 0.1 to 50 ng/ml concentration range for both compounds. The method was applied for the quantitative determination of deramciclane and its metabolite in human plasma samples during a food interaction pharmacokinetic study.

Oral, intraperitoneal and intravenous pharmacokinetics of deramciclane and its N-desmethyl metabolite in the rat.

The pharmacokinetic properties of deramciclane fumarate (EGIS-3886), a new potential anxiolitic agent, and its N-desmethyl metabolite have been investigated in Wistar rats after 10 mgkg(-1) deramciclane fumarate was administered orally, intraperitoneally or intravenously. A highly sensitive, validated and optimized gas chromatographic method with nitrogen selective detection (GC-NPD) using a solid-phase extraction technique was used to determine plasma levels of the parent compound and its N-desmethyl metabolite. After oral administration the absorption of the parent compound was very fast (t(max) 0.5h). The maximum plasma concentration (C(max)) was detected at 44.9, > or =177.8 and > or =2643.0 ngmL(-1) after oral, intraperitoneal and intravenous administration of deramciclane, respectively. For the metabolite the respective Cmax values were 32.0, > or =25.4 and 51.0 ngmL(-1). The pharmacokinetic curves of both the parent compound and its metabolite showed enterohepatic recirculation for all administration routes. The biological half-life (tbeta 1/2) for deramciclane ranged from 3.42 to 5.44 h and for the N-desmethyl metabolite the range was 2.90-5.44 h, after administration of the drug by the three different routes. After intravenous administration AUC0-infinity, of deramciclane was 29.2- and 5.4-times higher than that observed after oral and intraperitoneal treatment, respectively. These AUC0-infinity ratios were only 2.1- and 1.5-times higher for the metabolite. The absolute bioavailability of deramciclane in rats was 3.42% after oral and 18.49% after intraperitoneal administration. The comparative pharmacokinetic study of deramciclane in rat after the different administration routes showed fast absorption. Furthermore, plasma levels were found to be administration route-dependent, low bioavailability of the parent compound indicated an extremely fast and strong first-pass metabolism. The apparent volume of distribution suggested strong tissue binding after administration of the drug by any of the three routes studied.

Pharmacokinetics and safety of deramciclane during multiple oral dosing.

UNLABELLED: Deramciclane is a new putative non-benzodiazepine-type anxiolytic compound. It is a selective serotonin 5-HT(2A) and 5-HT(2C) receptor antagonist and has also inverse agonist properties. The aim of this study was to reveal the pharmacokinetics and tolerability of deramciclane during repeated oral dosing in healthy male volunteers. SUBJECTS, MATERIAL AND METHODS: A randomized double-blind, placebo-controlled design was used. The study had three consecutive groups that received first a single oral dose of 10, 30 and 60 mg of deramciclane followed by twice a day administration for seven days. The total number of subjects was 28. The pharmacokinetic parameters were calculated for a single dose and after repeated administration. Tolerability was assessed by monitoring safety laboratory variables, electrocardiogram, heart rate, blood pressure and adverse events. RESULTS: The steady-state was reached during the seven-day administration. The pharmacokinetics of deramciclane was dose-proportional at steady-state at each dose level. Deramciclane accumulated about three-fold during repeated administration. The relative bioavailability of deramciclane increased about 1.4-fold compared to that of a single dose at each dose level. The mean elimination half-life of deramciclane for 10, 30 and 60 mg doses prolonged from 24.3, 20.9 and 22.9 h after a single dose to 30.5, 25.6 and 28.7 h at steady-state, respectively. Only few adverse events were reported, all mild and transient in nature. The most frequently reported adverse drug reactions were tiredness and headache. There were no deramciclane-induced changes in the clinical chemistry or hematology variables, blood pressure, heart rate or in electrocardiogram. CONCLUSIONS: In conclusion, the pharmacokinetics of deramciclane is linear over the dose range of 10 - 60 mg at steady-state. The slight non-linearity within the dose levels during repeated administration of seven days was regarded as clinically irrelevant. Deramciclane was safe and well tolerated up to doses of 60 mg b.i.d. for seven days.

[Comparative pharmacokinetics of 800 mg of acyclovir-containing Telviran and Zovirax tablets in healthy volunteers]. / Telviran és Zovirax 800 mg acyclovir hatóanyagtartalmú tabletták összehasonlító farmakokinetikája egészséges önkénteseken.

The authors performed a detailed comparative clinical and pharmacokinetic study with two 800 mg acyclovir containing tablets, namely the Telviran (EGIS Pharmaceuticals Ltd.) and the Zovirax (Wellcome Foundation Ltd.). The determination of the detailed pharmacokinetic parameters and the relative bioavailability was carried out on 24 healthy male volunteers in a two way, open, randomised, cross-over design study after single dose administration. The plasma concentration of acyclovir was determined by a newly developed and validated highly sensitive (LLOQ = 10 ng/ml) HPLC-UV bioanalytical method after sample preparation with RP-18 solid phase extraction method (SPE). The individual pharmacokinetic parameters calculated from the time-plasma concentration curve (tmax, Cmax, AUC0-infinity, AUC0-16, AUC0-t, AUC0-z, AUCRest, t beta 1/2, MRT, Cmax/AUC0-infinity) were compared with statistical methods (ANOVA, ANOVAlog, Confidence interval, Schuirmann, Wilcoxon tests). On the basis of the results of the statistical evaluation and the clinical study, there was no significant difference found between the two acyclovir containing preparations. The comparative pharmacokinetic study demonstrated, that the relative bioavailability of the 800 mg Telviran and Zovirax tablets are equivalent and the two products are bioequivalent.

Application of overpressured layer chromatography combined with digital autoradiography and mass spectrometry in the study of deramciclane metabolism.

Overpressured layer chromatography was combined with the highly sensitive and rapid digital autoradiography (DAR) and mass spectrometry to separate, detect, and identify 3H- and 14C-labeled deramciclane metabolites in different biological matrixes. Several minor and major metabolites were separated from plasma and urine samples. The radioactive metabolites localized by DAR were scraped from the thin-layer chromatographic plate and transferred to a mass spectrometer for structure identification. Several metabolites were isolated and characterized, including hydroxy-N-desmethyl deramciclane, which is described in detail. The combination of techniques is efficient and has good sensitivity: about 2 micrograms metabolite from a biological matrix was isolated and identified this way.

Whole-body autoradiography and quantitative organ-level distribution study of deramciclane in rats.

The distribution of 3H-labelled deramciclane (EGIS-3886), a new 5-HT2 antagonist with anxiolytic activity, has been investigated by whole-body autoradiography and quantitative organ-level determination after intravenous and oral administration to male and female rats at a dose of 3 mg kg(-1). Pregnant dams were also studied, but by autoradiography only. In the autoradiographic study 32 organs were investigated, while in the quantitative organ-level study the radioactivity in 15 organs were determined. There are no sex differences in the distribution of deramciclane, absorption is rapid, elimination is comparatively fast, no specific organ is targeted, and the accumulation of the compound is very unlikely. Penetration of the blood-brain barrier was complete and extremely fast, a very important feature of a potential anxiolytic drug. There is no penetration of the foetus in pregnant dams. The study demonstrated that deramciclane has advantageous pharmacokinetic properties in rats.

The single dose pharmacokinetics and safety of deramciclane in healthy male volunteers.

The pharmacokinetics and tolerability of a new putative non-benzodiazepine type anxiolytic compound deramciclane was studied in two consecutive studies. An open dose-escalation design was used to study doses from 0.2 to 50 mg in 18 healthy male volunteers. In the second study doses from 50 to 150 mg were investigated in 14 healthy males in a double-blind, placebo-controlled, dose escalation study. Deramciclane was rapidly absorbed from the GI-tract and T(max) was 2-4 h. The elimination half-life increased from about 20 h to about 32 h with the increasing dose. Nevertheless, the AUC(0-infinity) values increased linearly within the studies over the dose ranges of 3-50 and 50-150 mg. However, the increase was more than the ratio of the dose over the total dose range of 3-150 mg. Therefore, non-linear pharmacokinetics of deramciclane at high doses cannot be excluded. N-desmethyl deramciclane, which is the active metabolite of deramciclane, was determined in plasma. C(max) was reached at about 6 h. The AUC(0-48 h) for the N-desmethyl metabolite was about one third of the AUC(0-infinity) of the parent compound and the ratio remained constant at each dose level. Deramciclane was safe, and was well tolerated at each dose level.

Pharmacokinetics of deramciclane in rabbits.

The pharmacokinetics of deramciclane (CAS 120444-78-8, EGIS-3886) was investigated in rabbits after i.v., p.o. and s.c. administration of 3 mg/kg 14C-phenyl-deramciclane. The plasma, concentration-time curves of total radioactivity, the parent compound (deramciclane) and its N-demethylated metabolite (EGIS-7056) were determined. The radioactivity level was measured by liquid scintillation technique while the concentration of the parent compound and its metabolite was determined by gas chromatography-mass spectrometry detection. The p.o. and i.v. studies were carried out on the same group of animals, while a separate group of rabbits was used for studying s.c. absorption. Deramciclane was readily absorbed after p.o. and s.c. treatment (tmax 1.0 to 1.4 h). The terminal elimination half-life (t1/2 beta) of the parent compound fell between 5.8 to 7.1 h, while that of the total radioactivity ranged from 21.6 and 26.0 h. The absolute bioavailability of deramciclane calculated from the AUC0-infinity values was found to be 43 and 60% after p.o. and s.c. treatment. The apparent volume of distribution (Vd) and the whole body clearance (Cl) of deramciclane after i.v. administration were 25.0 +/- 7.1 l/kg and 2.6 +/- 0.5 l/h/kg, respectively. The AUC0-infinity values of the parent compound varied between 4.6 and 7.9% of that of total radioactivity, suggesting that deramciclane was subjected to intensive metabolic conversion. The AUC0-infinity of N-desmethyl-deramciclane was 5.7%, compared to that of the parent compound after i.v. administration.