Development and evaluation of dexibuprofen formulation with fast onset and prolonged effect.

In the present study, in order to improve the solubility and bioavailability of poorly water-soluble dexibuprofen, a novel dexibuprofen-loaded solid dispersion was developed using the spray-drying technique. The controlled-release dexibuprofen formulation was developed by combining the immediate-release dispersion powder and the sustained-release formula. The solid dispersion composed of dexibuprofen/poloxamer 407/hydroxypropyl methylcellulose (HPMC) 2910 (50 cps)/sodium lauryl sulfate (SLS) (10/1/4/0.1 mg) was selected as the immediate-release formulation due to its increased solubility and dissolution rate. This immediate-release formulation showed a significantly higher initial plasma concentration, AUC, and Cmax of dexibuprofen than those of dexibuprofen powder. Based on the prolonged effect of high plasma concentration, the formulation consisting of dexibuprofen/ethylcellulose/HPMC 2910 (4000 cps)/magnesium stearate (66/16.5/16.5/1 mg) was selected as the sustained-release formulation. Finally, the controlled-release (CR) formulation was prepared by encapsulating the immediate-release and sustained-release formulations in hard gelatin capsules. The proposed CR formulation showed enhanced AUC (5.5-fold) and Cmax (3.5-fold) compared to dexibuprofen powder. The results of the present study suggest that the CR formulation containing dexibuprofen may be a potential oral dosage form for a fast onset and a prolonged effect of poorly water-soluble dexibuprofen.

Functional and cytometric examination of different human lung epithelial cell types as drug transport barriers.

To develop inhaled medications, various cell culture models have been used to examine the transcellular transport or cellular uptake properties of small molecules. For the reproducible high throughput screening of the inhaled drug candidates, a further verification of cell architectures as drug transport barriers can contribute to establishing appropriate in vitro cell models. In the present study, side-by-side experiments were performed to compare the structure and transport function of three lung epithelial cells (Calu-3, normal human bronchial primary cells (NHBE), and NL-20). The cells were cultured on the nucleopore membranes in the air-liquid interface (ALI) culture conditions, with cell culture medium in the basolateral side only, starting from day 1. In transport assays, paracellular transport across all three types of cells appeared to be markedly different with the NHBE or Calu-3 cells, showing low paracellular permeability and high TEER values, while the NL-20 cells showed high paracellular permeability and low TEER. Quantitative image analysis of the confocal microscope sections further confirmed that the Calu-3 cells formed intact cell monolayers in contrast to the NHBE and NL-20 cells with multilayers. Among three lung epithelial cell types, the Calu-3 cell cultures under the ALI condition showed optimal cytometric features for mimicking the biophysical characteristics of in vivo airway epithelium. Therefore, the Calu-3 cell monolayers could be used as functional cell barriers for the lung-targeted drug transport studies.

Iron casein succinylate-chitosan coacervate for the liquid oral delivery of iron with bioavailability and stability enhancement.

Iron casein succinylate (ICS) liquid oral preparation as iron supplement has uncomfortable taste after a long period of storage because of its stability, and poor bioavailability of iron compared to any other iron preparations. To improve the chemical stability of ICS and enhance the bioavailability of iron, chitosan-ICS nanoparticles (NPs) were prepared by complex coacervation method and stabilized with polyethylene glycol (PEG) 400. NPs were spherical (mean diameter of 830-1070 nm) with positive charge (+30-60 mV) depending on the composition of NPs. Addition of PEG400 (2 w/v %) increased the zeta potential (26-50 %) and physical stability of chitosan-ICS NPs suspension. Also, NPs decreased iron release compared to ICS after 7-weeks of storage at 4 °C. NPs markedly increased the permeability of iron in Caco-2 cell up to 32-38-fold compared to ICS, while physical mixture of chitosan and ICS increased the iron permeability only 2.5-fold. In summary, NPs improved the physicochemical stability and enhanced the transport of iron compared to other iron preparations in Caco-2 cell model. Thus, chitosan-ICS coacervate might be a promising candidate as a liquid oral iron delivery system for iron deficiency patients with stability and bioavailability enhancement.

Comparative effects of PEG-containing liposomal formulations on in vivo pharmacokinetics of streptokinase.

Streptokinase (SK) is an effective thrombolytic agent, but it has a short half-life due to its rapid elimination from the body. In this study, we prepared and evaluated polyethyleneglycol (PEG)-based liposomal formulations (PEG-liposomes) containing SK with a view toward prolonging its circulatory half-life. SK-bearing liposomes (SK-liposomes) were prepared using freeze-thaw method after film hydration and extrusion techniques, composed of phosphatidylcholine [egg phosphatidylcholine (EPC), dipalmitoyl PC, or distearoyl PC], cholesterol and cholesterol-3-sulfate with or without PEG. Their physicochemical properties were characterized by the measurement of size and zeta potential and incorporation efficiency. SK-liposomal formulations were applied to rats through a femoral vein via intravenous administration to compare the effects of liposomal delivery and PEG on the half-life of SK in blood. Free SK was used as a control. SK activities in plasma were measured to estimate the amidolytic activity of SK-plasminogen complex after rupturing liposomes with Triton X-100. Pharmacokinetic parameters were obtained from SK activity-time profiles. The SK-liposomes had a homogenous distribution of negatively charged nanoparticles at the range of 10-33% of the incorporation efficiencies of SK. Among the SK-liposomes, SK-EPC- and SK-EPC/PEG-liposomes had injectable diameters (<200 nm). SK was administered as free SK, SK-EPC-liposomes, or SK-EPC/PEG-liposomes for in vivo study. SK-EPC/PEG-liposomes had significantly greater the t(1/2), AUC(∞) and MRT values of SK than SK alone or SK-EPC-liposomes. These findings suggest that PEG-liposomal incorporation of SK enhances thrombolytic activity in vivo, and that such liposomes can be utilized to enhance the pharmacokinetic profiles of other therapeutic proteins with a short biological half-life.

Charge-mediated topical delivery of plasmid DNA with cationic lipid nanoparticles to the skin.

Cationic lipid nanoparticles (cLNs) were modified to develop a gene delivery system for topical use via a dermal route. The cLNs were formulated using high pressure homogenization method and were composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dioleoylphosphatidylethanolamine (DOPE), Tween 20, and tricaprin as a solid core (1:1:1:1.67, w/w). The prepared cLNs were nanoscale-sized (<100 nm) and were highly positive (51 mV). The cLN/DNA complexes demonstrated enhanced transfection potential in the cells at the optimal ratio without cytotoxic effects. To evaluate its efficacy in topical application, in vitro skin transfer of the cLN/DNA complexes was monitored using the measurement of the surface zeta potential of hairless mouse skin and validated using confocal microscopy of the sectioned skin. The in vivo delivery of plasmid DNA with the cLN formulation was examined using the relative expression levels of mRNA after non-invasive application with the cLN/DNA complexes on hair-removed dorsal skin of mice. The cLNs successfully transferred plasmid DNA to the skin, which was facilitated by the charge-mediated interaction between the cLN/DNA complexes and the skin. These results suggest the promising potential of cLNs as a topical gene delivery system for gene vaccine delivery and cutaneous gene therapy in preclinical and clinical applications.

Determination of cefdinir levels in rat plasma and urine by high-performance liquid chromatography-tandem mass spectrometry: application to pharmacokinetics after oral and intravenous administration of cefdinir.

A selective and sensitive liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed and validated for the determination of cefdinir in rat plasma and urine. Following a simple protein precipitation using methanol, chromatographic separation was achieved with a run time of 10 min using a Synergi 4 µ polar-RP 80A column (150 × 2.0 mm, 4 µm) with a mobile phase consisting of 0.1% formic acid in water and methanol (65:35, v/v) at a flow rate of 0.2 mL/min. The protonated precursor and product ion transitions for cefdinir (m/z 396.1 → 227.2) and cefadroxil, an internal standard (m/z 364.2 → 208.0) were monitored in the multiple reaction monitoring in positive ion mode. The calibration curves for plasma and urine were linear over the concentration range 10-10,000 ng/mL. The lower limit of quantification was 10 ng/mL. All accuracy values were between 95.1 and 113.0% and the intra- and inter-day precisions were <13.0% relative standard deviation. The stability under various conditions in rat plasma and urine was also found to be acceptable at three concentrations. The developed method was applied successfully to the pharmacokinetic study of cefdinir after oral and intravenous administration.

Design and evaluation of ondansetron liquid suppository for the treatment of emesis.

The thermosensitive-mucoadhesive ondansetron liquid suppository (tmOLS) was developed to enhance patient compliance and bioavailability in high-risk patients receiving highly emetogenic therapy and having difficulty in swallowing, The thermosensitive-mucoadhesive liquid suppository bases were formulated using poloxamers (P407 and P188) and hydroxypropylmethyl cellulose (HPMC). The physicochemical properties of the liquid suppository bases were characterized by their gelation temperature, mucoadhesive force, rheological properties, and in vitro release. Rectal mucosal damage following rectal administration of tmOLS in rats was assessed using microscopy. Pharmacokinetic analyses were performed to compare tmOLS administered via the rectal route to ondansetron solution administered orally. The liquid suppository base of tmOLS contained P407, P188, and HPMC in the ratio 18:20:0.8, was in the liquid state at room temperature, underwent gelation at body temperature. Area under the curve and half-life (t1/2) of ondansetron were significantly higher in the tmOLS-treated group, indicating that the formulation bypassed the first-pass metabolism and that it was released slowly from the tmOLS because of the formation of mucoadhesive gel state. Furthermore, the t1/2 of tmOLS was two-fold that of the oral solution. Thus, tmOLS could be administered to patients who have difficulty in swallowing; however, adjustments in dosing interval may be needed.

Effect of adjuvant on pharmacokinetics, organ distribution and humoral immunity of hepatitis B surface antigen after intramuscular injection to rats.

Two types of radioiodinated plasma driven antigens, heat-inactivated (¹²5I-h-HBsAg) and formalin-inactivated HBsAg (¹²5I-f-HBsAg) were investigated for the effect of immunoadjuvant, aluminium phosphate (AP) on pharmacokinetics, organ distribution and humoral immunity of differently inactivated hepatitis B surface antigens (HBsAg) in rats. As a result, most of h-HBsAg (90%) was retained and slowly eliminated from the injection site. The h-HBsAg was highly localized in regional lymph node (RLN), but resulted in low humoral immune response. On the other hand, f-HBsAg was less localized in the injection site and RLN, but mainly distributed into serum and liver (62.9 and 22.4%, respectively). However, both h-HBsAg and f-HBsAg slowly disappeared from the injection site with AP, resulting in the increased area under the amount-time curve (AUQ) of h-HBsAg and f-HBsAg in the injection site. Exposures of h-HBsAg and f-HBsAg in serum were increased (1.4 and 2.8 times increase in AUC, respectively) with AP. The RLN uptake of both antigens were dramatically increased (25 and 3.1 times increase in AUC, respectively) with higher humoral immune response. The antibody titres were also increased with AP. In conclusion, pharmacokinetics, organ distribution and humoral immunity of h-HBsAg were highly dependent on the inactivation method of antigen and the presence of immunoadjuvant such as AP.

Artemisia capillaris extracts as a green factory for the synthesis of silver nanoparticles with antibacterial activities.

We report a green synthesis of silver nanoparticles that uses extracts from the aerial part of Artemisia capillaris. Both water and 70% ethanol extracts successfully generated silver nanoparticles. The formation of silver nanoparticles was confirmed by surface plasmon resonance bands, Fourier transform-infrared spectra, high resolution-transmission electron and atomic force microscopic images. Various shapes of silver nanoparticles were generated with an average diameter of 29.71 nm with water extract and 29.62 nm with 70% ethanol extract. An improvement in antibacterial activity (MIC 8.35-16.7 microg/mL) was observed against a total of twenty different strains of Gram-negative and Gram-positive bacteria. A remarkable enhancement (approximately 12-fold) was observed against Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella oxytoca, and Klebsiella areogenes when compared with the extract alone. Silver nanoparticles produced by the 70% ethanol extract showed slightly higher antibacterial activity than those generated with the water extract. The correlation between total flavonoid content of each extract and the antibacterial activity did not exert any significant relationships. This report suggests that plant extracts have the potential to be used as powerful reducing agents for the production of biocompatible silver nanoparticles possessing enhanced antibacterial activities.

Long-term stable cationic solid lipid nanoparticles for the enhanced intracellular delivery of SMAD3 antisense oligonucleotides in activated murine macrophages.

PURPOSE: Long-term stable cationic solid lipid nanoparticles (cSLNs) were formulated to transfer SMAD3 antisense oligonucleotides (ASOs) into the cells to enhance the intracellular activity of the ASOs. The SMAD3 ASOs were designed to block the inflammatory processes linked to TGFß/SMAD3 pathway. METHODS: The cSLN formulation was prepared by high-pressure homogenization method composed of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP), dioleoylphosphoethanolamine (DOPE), Tween 20, and tricaprin as a solid lipid core (1:1:1:1.67, w/w). The size and the zeta potential of the prepared cSLNs were measured by light scattering. The cSLN/ASO complexes were generated and introduced into the murine macrophage cells. After the treatment of the complexes, the cellular uptake of the complexes was determined by flow cytometry and the intracellular activity of SMAD3 ASOs from the complexes was evaluated by western blotting of SMAD3. In addition, TGFß1, an upstream molecule of TGFß/SMAD3 pathway, was monitored by ELISA. RESULTS: The nano-scale sized cSLNs were positively charged and physically stable at 4oC during the storage up to 24 months. The uptake efficiency of the cSLN/ASO complexes into macrophage cells was enhanced up to 80% without cytotoxicity. After the treatment of the cSLN/ASO complexes, SMAD3 as well as TGFß1 was significantly suppressed based on the SMAD3 ASO activity in the macrophage cells. In addition, the cSLN/ASO complexes prevented the morphological change to dendritic shape in the activated macrophage cells. CONCLUSION: These results suggest that the cSLNs have a potential to deliver the SMAD3 ASOs to intracellular compartments for the anti-inflammatory effect. The development of this strategy might lead to anti-inflammatory and anti-fibrotic therapies in immunological disorders.

Antibacterial activity and increased freeze-drying stability of sialyllactose-reduced silver nanoparticles using sucrose and trehalose.

The resistance to current antibiotics results in the emergence of health-threatening bacteria. Silver nanoparticles are known to exhibit broad-spectrum antibacterial activities without the development of resistance. Herein, we developed a green synthetic method for the preparation of silver nanoparticles with sialyllactose instead of toxic chemicals as a reducing agent, which would improve its therapeutic applicability and increase its biocompatibility. Oven incubation, autoclaving and microwave irradiation methods were applied to prepare the silver nanoparticles. High resolution-transmission electron microscopy and atomic force microscopy images revealed mostly spherical and amorphous silver nanoparticles with an average diameter of 23.64 nm. Fourier Transform-infrared spectra suggest that the N-H amide of sialyllactose might be involved in the binding of silver nanoparticles. Based on thermogravimetric analyses, 2,3-sialyllactose-reduced silver nanoparticles are composed of 54.3 wt% organic components and 45.7 wt% metallic silver. Enhanced antibacterial activities of silver nanoparticles (approximately 8-fold) were observed against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhimurium (minimum inhibitory concentration 16 microg/mL). Next, we employed the use of carbohydrate stabilizers to increase the stability of silver nanoparticles during a freeze-drying process. It was found that sucrose and trehalose were the most effective stabilizers. In addition, silver nanoparticles possessed excellent salt stability as well as on-the-shelf stability in the presence of these stabilizers. Derivatives of sialic acid are known to be anti-influenza agents; therefore, the newly prepared silver nanoparticles may serve as useful antibacterial and antiviral agents to cope with both pathogenic bacteria and viruses in the near future.

Simplified analysis of lipoprotein lipase activity: evaluation of lipasemic activity of low molecular weight heparin in rats.

A simple procedure for measuring lipoprotein lipase activity was developed by using newly formulated substrate with turbidimetry method. The activity of lipoprotein lipase was expressed as Y (value) (%) that was calculated by measuring UV absorbance (600 nm) at two time points (30 sec and 15 min). Lipid emulsions as the substrate and other factors affecting the lipolytic activity of lipase were studied. The optimal conditions for an in vitro experiment were found to be with LIPOMCT as lipid substrate at 37°C in tris-HCl buffer (pH 7.4) in the presence of BSA. To evaluate an in vivo applicability, low molecular weight heparin (LMWH)-containing drug, Sulodexide, was administered to the rats. The serum from LMWH-administered rats was incubated in an optimized analytical condition without BSA. As expected, increasing the amount of LMWH administered led to higher lipase activity. The newly developed method was successfully applied to an in vivo model suggesting the potential to be applicable for the pharmacodynamic studies of commercially available products of LPL analogues in human subjects, and for the diagnosis of acute pancreatitis in the clinical laboratory.

Cellular delivery of cationic lipid nanoparticle-based SMAD3 antisense oligonucleotides for the inhibition of collagen production in keloid fibroblasts.

SMAD3 is a key player in the TGFß signaling pathway as a primary inducer of fibrosis. The inhibition of SMAD3 production is one strategy to alleviate fibrosis in keloid fibroblasts. In the present study, antisense oligonucleotides (ASOs) against SMAD3 were designed to specifically block the expression of SMAD3. The cationic lipid nanoparticles (cLNs) were formulated to enhance an intracellular activity of SMAD3 ASOs in keloid fibroblasts. This formulation was prepared using melt-homogenization method, composed of 3-[N-(N',N'-dimethylaminoethane)-carbamol] cholesterol (DC-Chol), dioleoylphosphatidylethanolamine (DOPE), Tween20, and trimyristin as a lipid core (1:1:1:1.3, w/w). The size and zeta potential of cLNs and cLN/ASO complexes were measured using light scattering. AFM was used to confirm the morphology and the size distribution of cLNs and cLN/ASO complexes. The prepared cLNs had a nano-scale sized spherical shape with highly positive charge, which were physically stable without aggregation during the storage. The cLN/SMAD3 ASO complexes were successfully generated and internalized onto keloid fibroblasts without toxicity. After the treatment with cLN/ASO complexes, SMAD3 was inhibited and collagen type I was also significantly suppressed in keloid fibroblasts. These results suggest that SMAD3 ASOs complexed with cLNs have a therapeutic potential to suppress collagen deposition in fibrotic diseases. Therefore, this strategy might be developed to lead to anti-fibrotic therapies.

Isolation and identification of steroidogenic peptides from calf spleen.

Since women with climacteric syndrome have significantly lower serum levels of estradiol and other related hormones, hormone replacement therapies (HRT) such as estrogen are needed to lessen symptoms. However, HRT can often cause severe adverse effects that include many cancers and stroke. Therefore, new and novel approaches to relieve climacteric syndrome still need to be developed. The aim of this study was to identify biologically active peptides from calf spleen that are responsible for stimulating biosynthesis of steroid hormone and to explore the potential of isolated peptides as therapeutic agents for menopausal syndrome. The reverse phase HPLC system was used to isolate active compounds from calf spleen extract, a cell culture system was used to screen the activity of stimulating hormone secretion, and Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometry was used for molecular weight determination. In the present study, two calf steroidogenic peptides, CSP-1 (MW; 4.655 kDa) and CSP-2 (MW; 8.331 kDa), were isolated and identified from calf spleen and may be putative climacteric syndrome therapeutic agents.

Development of chitosan-based ondansetron buccal delivery system for the treatment of emesis.

BACKGROUND: For the buccal drug delivery, chitosan (CS) can be used to improve drug absorption and reduce application frequency and drug amount. The aim of this study is to develop and evaluate mucoadhesive ondansetron buccal films for the treatment of emesis using CS as a mucoadhesive polymer. METHODS: The film prepared by solvent casting method was comprised of ondansetron (approximately 65 µg)-loaded mucoadhesive gels containing 1, 2 or 3% CS and impermeable backing layer. Rheological property of the gels, physiochemical properties of the films (weight, thickness, drug content, swelling ratio, adhesion time and mucoadhesive force) and in vitro ondansetron release profile from the films were determined to evaluate the formulation. The films containing 3% CS (diameter: 0.5 cm; thickness: 170 µm) was selected as the novel formulation, and were used for the in vivo study. Comparative pharmacokinetic studies of ondansetron with this film and oral solution were performed at the same dose in hamsters. RESULTS: The mean values of T(max) and C(max) of the film and oral solution were similar. However, the half-life, mean residence time and AUC(0-24 h) of the film were about 1.7, 1.4 and 2.0-fold higher than those of the oral solution, respectively. The film showed enhanced bioavailability and prolonged efficacy compared to the oral solution. CONCLUSIONS: The mucoadhesive ondansetron buccal film may be a potential alternative to the marketed oral formulation, parenterals and solid suppositories with better patient compliance and higher bioavailability for the treatment of emesis.

Detection of malathion, fenthion and methidathion by using heparin-reduced gold nanoparticles.

Green-synthesized gold nanoparticles were utilized for the detection of organophosphorous pesticides. Heparin, one of glycosaminoglycans, was used as a reducing and stabilizing agent. The reaction conditions were optimized, and high resolution-transmission electron microscopic images revealed gold nanoparticles of various shapes. Organophosphorous pesticides in water were detected by simply mixing them with gold nanoparticles. NaCl induced a color change in the mixed solution from wine-red to purple-blue that was dependent on the pesticide concentration in the range of 10-1,000 ppb. Gold nanoparticles were immobilized on a silica gel matrix in order to prepare solid supports for removing pesticides. The incorporation of atomic gold and heparin bound to 2 g of silica gel was determined 4,058 ppm and 33 microg as measured by inductively coupled plasma-atomic emission spectrophotometry and carbazole assay, respectively. AuNPs-immobilized silica gel columns were successfully applied for removing fenthion in water confirmed by RP-HPLC and FT-IR analyses.

Development of coated nifedipine dry elixir as a long acting oral delivery with bioavailability enhancement.

To develop the long acting nifedipine oral delivery with bioavailability enhancement, a nifedipine dry elixir (NDE) containing nifedipine ethanol solution in dextrin shell was prepared using a spray-dryer, and then coated nifedipine dry elixir (CNDE) was prepared by coating NDE with Eudragit acrylic resin. The physical characteristics and bioavailability of NDE and CNDE were evaluated, and then compared to those of nifedipine powder. NDE and CNDE, which were spherical in shape, had about 6.64 and 8.68-8.75 µm of geometric mean diameters, respectively. The amount of nifedipine dissolved from NDE for 60 min increased about 7- and 40-fold compared to nifedipine powder in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, respectively. Nifedipine released from CNDE was retarded in both dissolution media compared with that from NDE. After oral administration of NDE, the C(max) and AUC(0→8h) of nifedipine in rat increased about 13- and 7-fold, respectively, and the Tmax of nifedipine was reduced significantly compared with those after oral administration of nifedipine powder alone. The AUC(0→8h) and T(max) of nifedipine in CNDE increased markedly and the C(max) of nifedipine in CNDE was significantly reduced compared to those in NDE. It is concluded that CNDE, which could lower the initial burst-out plasma concentration and maintain the plasma level of nifedipine over a longer period with bioavailability enhancement, might be one of potential alternatives to the marketed long acting oral delivery system for nifedipine.

Effect of subconjunctivally injected liposome-encapsulated tissue plasminogen activator on the absorption rate of subconjunctival hemorrhages in rabbits.

PURPOSE: To evaluate the effect of subconjunctivally injected liposome-encapsulated tissue plasminogen activator (tPA) on the absorption rate of subconjunctival hemorrhages (SHs). METHODS: SHs were induced in 1 eye each of 36 rabbits by subconjunctival injection of 0.05 mL of autologous blood. After 8 hours, randomized subconjunctival injections were performed: 26,000 IU/mL liposome-encapsulated tPA (0.05 mL) in 9 eyes (group A), free-form tPA (26,000 IU/mL; 0.05 mL) in 9 eyes (group B), only liposomes (0.05 mL) in 9 eyes (group C), or no injection in 9 eyes (group D). The sizes of the SHs at 8, 24, 48, 72, 96, and 120 hours after induction were measured using an image analyzer and were compared among the 4 groups. RESULTS: Group A showed significantly more rapid absorption rates than all the other groups at 24, 48, and 72 hours and had the significantly shortest mean elapsed time for the complete resorption of SHs. The tPA activity in ocular tissue except conjunctiva and plasma were negligible beyond 24 hours after SH induction with both forms of tPA. In the conjunctiva, the tPA activity was significantly prolonged in the liposome-encapsulated tPA group than in the free tPA group. CONCLUSIONS: Subconjunctival injection of liposome-encapsulated tPA seems to enhance SH absorption in rabbits, especially during the early stages with minimal systemic and ocular absorption.

Reverse-phase liquid chromatography with electrospray ionization/mass spectrometry for the quantification of pseudoephedrine in human plasma and application to a bioequivalence study.

A sensitive and selective reverse-phase liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method was developed and validated to quantify pseudoephedrine (CAS 90-82-4) in human plasma. Phenacetin was used as the internal standard (I.S.). Sample preparation was performed with a deproteinization step using acetonitrile. Pseudoephedrine and I.S. were successfully separated using gradient elution with 0.5% trifluoroacetic acid (TFA) in water and 0.5% TFA in methanol at a flow-rate of 0.2 mL/min. Detection was performed on a single quadrupole mass spectrometer by a selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The ESI source was set at positive ionization mode. The ion signals of m/z 166.3 and 180.2 were measured for the protonated molecular ions of pseudoephedrine and I.S., respectively. The lower limit of quantification (LLOQ) of pseudoephedrine in human plasma was 10 ng/mL and good linearity was observed in the range of concentrations 10-500 ng/mL (R2 = 1). The intra-day accuracy of the drug containing plasma samples was more than 97.60% with a precision of 3.99-11.82%. The inter-day accuracy was 99.36% or more, with a precision of 7.65-18.42%. By using this analytical method, the bioequivalence study of the pseudoephedrine preparation was performed and evaluated by statistical analysis of the log transformed mean ratios of pharmacokinetic parameters. All the results fulfilled the standard criteria of bioequivalence, being within the 80-125% range which is required by the Korea FDA, US FDA, and EMEA to conclude bioequivalence. Consequently, the developed reverse-phase LC-ESI-MS method was successfully applied to bioequivalence studies of pseudoephedrine in healthy male volunteers.

Retained topical delivery of 5-aminolevulinic acid using cationic ultradeformable liposomes for photodynamic therapy.

5-Aminolevulinic acid (5-ALA), inducing photodynamic protoporphyrin (PpIX), is a hydrophilic molecule, resulting in leashing the capacity to cross tissue barriers like stratum corneum (SC) of skin. Here, we aimed to develop 5-ALA loaded ultradeformable liposomes (UDL) with different surface charges, and to investigate their physicochemical characteristics and capability for the skin penetration and retention of 5-ALA for topical photodynamic therapy (PDT). The effects of surface charges of UDL on in vitro permeation of 5-ALA and in vivo accumulation of 5-ALA-induced PpIX in viable skin were determined and then compared with conventional neutral liposomes (nLiposome). All UDL showed smaller particle size and better deformability than nLiposome. However, entrapment efficiency of 5-ALA was similar to each vesicle. Among vesicles, the cationic UDL (cUDL) demonstrated higher stability and permeability, and could deliver 5-ALA into deep skin tissue by topical application. Moreover, the 5-ALA loaded in cUDL was long retained, and induced more amount of PpIX in viable skin than those in other UDL and nLiposome. Considering that the conversion of 5-ALA into PpIX occurs preferentially in epidermis, these results suggested that topical delivery of 5-ALA loaded in cUDL could be an interesting proposal to optimize PDT related to 5-ALA.