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1.

Purpose

This study aims to develop liposomal formulations containing synergistic antibiotics of colistin and ciprofloxacin for the treatment of infections caused by multidrug-resistant Pseudomonas aeruginosa.

Methods

Colistin (Col) and ciprofloxacin (Cip) were co-encapsulated in anionic liposomes by ammonium sulfate gradient. Particle size, encapsulation efficiency, in vitro drug release and in vitro antibiotic activities were evaluated.

Results

The optimized liposomal formulation has uniform sizes of approximately 100 nm, with encapsulation efficiency of 67.0% (for colistin) and 85.2% (for ciprofloxacin). Incorporation of anionic lipid (DMPG) markedly increased encapsulation efficiency of colistin (from 5.4 to 67.0%); however, the encapsulation efficiency of ciprofloxacin was independent of DMPG ratio. Incorporation of colistin significantly accelerated the release of ciprofloxacin from the DMPG anionic liposomes. In vitro release of ciprofloxacin and colistin in the bovine serum for 2 h were above 70 and 50%. The cytotoxicity study using A549 cells showed the liposomal formulation is as non-toxic as the drug solutions. Liposomal formulations of combinations had enhanced in vitro antimicrobial activities against multidrug resistant P. aeruginosa than the monotherapies.

Conclusions

Liposomal formulations of two synergistic antibiotics was promising against multidrug resistant P. aeruginosa infections.
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2.

Objective

To examine whether in vitro and ex vivo measurements of topical drug product performance correlate with in vivo outcomes, such that more efficient experimental approaches can be reliably and reproducibly used to establish (in)equivalence between formulations for skin application.

Materials and Methods

In vitro drug release through artificial membranes, and drug penetration into porcine skin ex vivo, were compared with published human in vivo studies. Two betamethasone valerate (BMV) formulations, and three marketed econazole nitrate (EN) creams were assessed.

Results

For BMV, the stratum corneum (SC) uptake of drug in 6 h closely matched data observed in vivo in humans, and distinguished between inequivalent formulations. SC uptake of EN from the 3 creams mirrored the in vivo equivalence in man (both clinically and via similar tape-stripping experiments). However, EN clearance from SC ex vivo did not parallel that in vivo, presumably due to the absence of a functioning microcirculation. In vitro release of BMV from the different formulations did not overlap with either ex vivo or in vivo tape-stripping data whereas, for EN, a good correlation was observed. No measurable permeation of either BMV or EN was detected in a 6-h in vitro skin penetration experiment.

Conclusions

In vitro and ex vivo methods for topical bioequivalence determination can show correlation with in vivo outcomes. However, these surrogates have understandable limitations. A “one-size-fits-all” approach for topical bioequivalence evaluation may not always be successful, therefore, and the judicious use of complementary methods may prove a more effective and reliable strategy.
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3.

Purpose

We developed simulation and modeling methods to predict the in vivo pharmacokinetic profiles of acyclovir, following escalating oral doses of valacyclovir, in wildtype and Pept1 knockout mice. We also quantitated the contribution of specific intestinal segments in the absorption of valacyclovir in these mice.

Methods

Simulations were conducted using a mechanistic advanced compartmental absorption and transit (ACAT) model implemented in GastroPlus?. Simulations were performed for 3 h post-dose in wildtype and Pept1 knockout mice following single oral doses of 10, 25, 50 and 100 nmol/g valacyclovir, and compared to experimentally observed plasma concentration-time profiles of acyclovir.

Results

Good fits were obtained in wildtype and Pept1 knockout mice. Valacyclovir was primarily absorbed from duodenum (42%) and jejunum (24%) of wildtype mice, with reduced uptake from ileum (3%) and caecum/colon (1%), for a total of 70% absorption. In contrast, the absorption of valacyclovir in Pept1 knockout mice was slow and sustained throughout the entire intestinal tract in which duodenum (4%), jejunum (14%), ileum (10%) and caecum/colon (12%) accounted for a total of 40% absorption.

Conclusion

The ACAT model bridged the gap between in situ and in vivo experimental findings, and facilitated our understanding of the complicated intestinal absorption processes of valacyclovir.
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4.

Purpose

Polymer-xerogel composite materials have been introduced to better optimize local anesthetics release kinetics for the pain management. In a previous study, it was shown that by adjusting various compositional and nano-structural properties of both inorganic xerogels and polymers, zero-order release kinetics over 7 days can be achieved in vitro. In this study, in vitro release properties are confirmed in vivo using a model that tests for actual functionality of the released local anesthetics.

Methods

Composite materials made with tyrosine-polyethylene glycol(PEG)-derived poly(ether carbonate) copolymers and silica-based sol–gel (xerogel) were synthesized. The in vivo release from the composite controlled release materials was demonstrated by local anesthetics delivery in a rat incisional pain model.

Results

The tactile allodynia resulting from incision was significantly attenuated in rats receiving drug-containing composites compared with the control and sham groups for the duration during which natural healing had not yet taken place. The concentration of drug (bupivacaine) in blood is dose dependent and maintained stable up to 120 h post-surgery, the longest time point measured.

Conclusions

These in vivo studies show that polymer-xerogel composite materials with controlled release properties represent a promising class of controlled release materials for pain management.
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5.

Purpose

To evaluate the use of Labrafil® M2125CS as a lipid vehicle for danazol. Further, the possibility of predicting the in vivo behavior with a dynamic in vitro lipolysis model was evaluated.

Methods

Danazol (28 mg/kg) was administered orally to rats in four formulations: an aqueous suspension, two suspensions in Labrafil® M2125CS (1 and 2 ml/kg) and a solution in Labrafil® M2125CS (4 ml/kg).

Results

The obtained absolute bioavailabilities of danazol were 1.5?±?0.8%; 7.1?±?0.6%; 13.6?±?1.4% and 13.3?±?3.4% for the aqueous suspension, 1, 2 and 4 ml Labrafil® M2125CS per kg respectively. Thus administration of danazol with Labrafil® M2125CS resulted in up to a ninefold increase in the bioavailability, and the bioavailability was dependent on the Labrafil® M2125CS dose. In vitro lipolysis of the formulations was able to predict the rank order of the bioavailability from the formulations, but not the absorption profile of the in vivo study.

Conclusions

The bioavailability of danazol increased when Labrafil® M2125CS was used as a vehicle, both when danazol was suspended and solubilized in the vehicle. The dynamic in vitro lipolysis model could be used to rank the bioavailabilities of the in vivo data.
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6.

Purpose

The clinical use of Epirubicin (Epi), as an anthracycline drug, is limited because of its cardiotoxicity. Here, an Epirubicin (Epi)-modified polyvalent aptamer system (MPAS) conjugate was developed for the treatment of both murine colon carcinoma cells (C26) and breast cancer cells (MCF-7).

Methods

Epi-MPAS conjugate formation was evaluated by fluorometric analysis. Release profiles of Epi from the developed conjugate were analyzed at pHs 5.4 and 7.4. For MTT assay (cytotoxic study) C26 and MCF-7 (target cells) and CHO cells (Chinese hamster ovary cell, nontarget) were treated with Epi, MPAS and Epi-MPAS conjugate. Internalization was assessed by fluorescence imaging and flow cytometry analysis. The designed conjugate was used for prohibition of tumor growth in vivo.

Results

Release of Epi from the Epi-MPAS conjugated was pH-dependent (more release at pH 5.5). Flow cytometry analysis and MTT assay showed that Epi-MPAS conjugate could significantly enhance the cellular uptake of Epi and increase its cytotoxicity in target cells as compared with non-targeted cell (CHO). Additionally, this complex could efficiently prohibit the tumor growth in vivo.

Conclusion

In conclusion, the developed drug delivery system had the characteristics of efficient Epi loading, pH-dependent drug release and tumor targeting in vitro and in vivo.
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7.

Purpose

Performance of a transdermal delivery system (TDS) can be affected by exposure to elevated temperature, which can lead to unintended safety issues. This study investigated TDS and skin temperatures and their relationship in vivo, characterized the effective thermal resistance of skin, and identified the in vitro diffusion cell conditions that would correlate with in vivo observations.

Methods

Experiments were performed in humans and in Franz diffusion cells with human cadaver skin to record skin and TDS temperatures at room temperature and with exposure to a heat flux. Skin temperatures were regulated with two methods: a heating lamp in vivo and in vitro, or thermostatic control of the receiver chamber in vitro.

Results

In vivo basal skin temperatures beneath TDS at different anatomical sites were not statistically different. The maximum tolerable skin surface temperature was approximately 42–43°C in vivo. The temperature difference between skin surface and TDS surface increased with increasing temperature, or with increasing TDS thermal resistance in vivo and in vitro.

Conclusions

Based on the effective thermal resistance of skin in vivo and in vitro, the heating lamp method is an adequate in vitro method. However, the in vitro-in vivo correlation of temperature could be affected by the thermal boundary layer in the receiver chamber.
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8.

Purpose

Multidrug resistance-associated protein 2 (MRP2/ABCC2) is an efflux pump that removes drugs and chemicals from cells. We sought to characterize the expression, trafficking and in vitro activity of seven single nucleotide polymorphisms (SNPs) in the ABCC2 gene.

Methods

ABCC2 SNPs were generated using site-directed mutagenesis and stably expressed in Flp-In HEK293 cells, which allows targeted insertion of transgenes within the genome. Total and cell surface expression of MRP2 as well as accumulation of substrates (calcein AM and 5(6)-carboxy-2′,7′-dichlorofluorescein diacetate, CDCF) were quantified in cells or inverted membrane vesicles expressing wild-type (WT) or variant forms.

Results

The cell surface expression of the C-24T-, G1249A-, G3542T-, T3563A-, C3972T- and G4544A-MRP2 variants was similar to WT-MRP2. While expression was similar, transport of calcein AM was enhanced in cells expressing the G3542T-, T3563A-, C3972T-, and G4544A-MRP2 variants. By comparison, cells expressing the C2366T-MRP2 variant had 40–50% lower surface expression, which increased the accumulation of calcein AM up to 3-fold. Accumulation of CDCF in inverted membrane vesicles expressing the C2366T-MRP2 variant was also reduced by 50%. In addition, the G1249A-MRP2 variant had decreased transport of CDCF.

Conclusions

Taken together, these data demonstrate that genetic variability in the ABCC2 gene influences the in vitro expression, trafficking, and transport activity of MRP2.
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9.

Purpose

A delayed release bio-polymeric Dual-Biotic system has been extensively evaluated in this study to overcome the therapeutic issue of probiotic killing due to incorrect administration with the antibiotic.

Methods

In vitro and ex vivo release and characterization studies have been undertaken on the Dual-Biotic system. In vivo analyses utilizing a Large White pig model were also performed with commercial products used as a comparison. Intestinal fluid for probiotic quantification was aspirated using a surgically implanted intestinal cannula with Lactobacillus acidophilus cell counts determined through luminescence and inoculation onto Lactobacilli-specific agar. Plasma amoxicillin concentrations were determined through Ultra-Performance Liquid Chromatography. The reactional profile and crosslinking mechanism of ovalbumin and genipin was elucidated using molecular mechanic energy relationships in a vacuum system by exploring the spatial disposition of different concentrations of genipin with respect to ovalbumin with ovalbumin/genipin ratios of 1:1, 1:5 and 1:10.

Results

In vivo evaluation of the Dual-Biotic system detailed maximum Lactobacillus viability (~455% baseline viability) 6 h after oral administration. Concurrent administration of the commercial products revealed a 75% decrease in bacterial viability when compared to the controls analyzed. A level A in vitro-in vivo correlation was also established with 96.9% predictability of amoxicillin release ascertained. The computational results achieved corroborated well with the experimental findings and physicochemical data.

Conclusions

Evaluation and correlation of the Dual-Biotic system has detailed the success of the formulation for the concurrent delivery of an antibiotic and probiotic.
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10.

Purpose

FCGRT encodes the alpha-chain component of the neonatal Fc receptor (FcRn). FcRn is critical for the trafficking of endogenous and exogenous IgG molecules and albumin in various tissues. Few regulators of FcRn expression have been identified. We investigated the epigenetic regulation of FcRn by two microRNAs (hsa-miR-3181 and hsa-miR-3136-3p) acting on FCGRT.

Methods

The binding of candidate microRNAs to the 3′-untranslated region of FCGRT was evaluated using luciferase reporter constructs in CHO cells. The effect of microRNAs on FCGRT mRNA and FcRn protein expression was evaluated using specific microRNA mimics and inhibitor transfections in A549, HEK293 and HepG2 cells.

Results

Hsa-miR-3181 mimic reduced luciferase reporter activity by 70.1% (10 nM, P <?0.0001). In A549, HEK293 and HepG2 cells, hsa-miR-3181 decreased FCGRT mRNA expression (48.6%, 51.3% and 43.5% respectively, 25 nM, P <?0.05). The hsa-miR-3181 mimic decreased the expression of FcRn protein by 40% after 48 h (25 nM, P <?0.001). The mature form of hsa-miR-3181 was detected in samples of human liver.

Conclusions

These data suggest that hsa-miR-3181 is an epigenetic regulator of FCGRT expression. The identification of this regulator of FCGRT may provide insights into a potential determinant of interindividual variability in FcRn expression.
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11.

Purpose

To determine the in vitro sub-cellular localization and in vivo efficacy of chitosan/GMO nanostructures containing paclitaxel (PTX) compared to a conventional PTX treatment (Taxol®).

Methods

The sub-cellular localization of coumarin-6 labeled chitosan/GMO nanostructures was determined by confocal microscopy in MDA-MB-231 cells. The antitumor efficacy was evaluated in two separate studies using FOX-Chase (CB17) SCID Female-Mice MDA-MB-231 xenograph model. Treatments consisted of intravenous Taxol® or chitosan/GMO nanostructures with or without PTX, local intra-tumor bolus of Taxol® or chitosan/GMO nanostructures with or without PTX. The tumor diameter and animal weight was monitored at various intervals. Histopathological changes were evaluated in end-point tumors.

Results

The tumor diameter increased at a constant rate for all the groups between days 7-14. After a single intratumoral bolus dose of chitosan/GMO containing PTX showed significant reduction in tumor diameter on day 15 when compared to control, placebo and intravenous PTX administration. The tumor diameter reached a maximal decrease (4-fold) by day 18, and the difference was reduced to approximately 2-fold by day 21. Qualitatively similar results were observed in a separate study containing PTX when administered intravenously.

Conclusion

Chitosan/GMO nanostructures containing PTX are safe and effective administered locally or intravenously. Partially supported by DOD Award BC045664
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12.

Purpose

To develop and validate a Level A in vitro-in vivo correlation (IVIVC) for potassium chloride extended-release (ER) formulations.

Methods

Three prototype ER formulations of potassium chloride with different in vitro release rates were developed and their urinary pharmacokinetic profiles were evaluated in healthy subjects. A mathematical model between in vitro dissolution and in vivo urinary excretion, a surrogate for measuring in vivo absorption, was developed using time-scale and time-shift parameters. The IVIVC model was then validated based on internal and external predictability.

Results

With the established IVIVC model, there was a good correlation between the observed fraction of dose excreted in urine and the time-scaled and time-shifted fraction of the drug dissolved, and between the in vitro dissolution time and the in vivo urinary excretion time for the ER formulations. The percent prediction error (%PE) on cumulative urinary excretion over the 24 h interval (Ae0–24h) and maximum urinary excretion rate (Rmax) was less than 15% for the individual formulations and less than 10% for the average of the two formulations used to develop the model. Further, the %PE values using external predictability were below 10%.

Conclusions

A novel Level A IVIVC was successfully developed and validated for the new potassium chloride ER formulations using urinary pharmacokinetic data. This successful IVIVC may facilitate future development or manufacturing changes to the potassium chloride ER formulation.
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13.

Purpose

Over expression of ATP-binding cassette transporters is considered one of the major reasons for non-responsiveness to antiepileptic drugs. Carbamazepine (CBZ), one of first line antiepileptic drug is known to influence ABCC2 expression but its exact molecular mechanism is unknown.

Methods

We investigated the effect of CBZ on expression of ABCC2 and pregnane X receptor (PXR) in HepG2 cell line and compared with hyperforin (agonist of PXR) and ketoconazole (antagonist of PXR) through realtime PCR and western blot assay. Involvement of PXR was demonstrated through nuclear translocation and RNA interference and related effect of CBZ on ABCC2 through functional activity assay. Molecular docking and dynamic simulation approach was used to understand the interaction of CBZ with PXR.

Results

CBZ and hyperforin increased the PXR and ABCC2 expression whereas reversed when present it in combination with ketoconazole. Experiments confirmed CBZ induced ABCC2 expression is PXR dependent. Molecular dynamic (MD) simulation and in vitro experiment indicated possibility of CBZ to be PXR agonist and PXR residue Gln285 to be important for CBZ-PXR interaction.

Conclusions

CBZ alters the functional activity of ABCC2 through PXR, which in turn can interfere with therapy. Mutational analysis of residues revealed the importance of Gln285 in ligand interaction.
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14.

Purpose

This study examined whether a CYP2D6 polymorphism (CYP2D6*4) was related to beta-blocker maintenance dose in patients with heart failure.

Methods

Logistic regression modeling was utilized in a retrospective chart-review analysis of heart-failure patients (60% Male, 90% of European descent) to assess whether CYP2D6*4 (non-functional CYP2D6 allele present in 1 of 5 individuals of European descent) is associated with maintenance dose of carvedilol (n?=?65) or metoprolol (n?=?33).

Results

CYP2D6*4 was associated with lower maintenance dose of metoprolol (OR 0.13 [95% CI 0.02–0.75] p?=?0.023), and a trend was observed between CYP2D6*4 and higher maintenance dose of carvedilol (OR 2.94 [95% CI 0.84–10.30] p?=?0.093). None of the patients that carried CYP2D6*4 achieved the recommended target dose of metoprolol (200 mg/day).

Conclusion

Consistent with the role of CYP2D6 in the metabolism of metoprolol, the tolerated maintenance dose of metoprolol was lower in CYP2D6*4 carriers compared to non-carriers. Consistent with the role of CYP2D6 in activation of carvedilol, tolerated maintenance dose of carvedilol was higher in CYP2D6*4 carriers compared to non-carriers. Further investigation is warranted to ascertain the potential of CYP2D6 as a potential predictive biomarker of beta-blocker maintenance dose in heart failure patients.
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15.

Purpose

The present study investigated the immunogenic potential of different cationic liposome formulations with a DNA plasmid encoding Pfs25, a malaria transmission-blocking vaccine candidate.

Methods

Pfs25 plasmid DNA was complexed with cationic liposomes to produce lipoplexes at different charge ratios of the cationic lipid head group to the nucleotide phosphate (N:P). The formation of lipoplexes was visualized by Cryogenic-TEM. Confocal microscopy of lipoplexes formed with GFP encoding plasmid DNA, and flow cytometry was used to determine their in vitro transfection capability. Two different lipoplex formulations using plasmid DNA encoding Pfs25 were evaluated for in vivo immunogenicity after intramuscular administration in Balb/c mice. Immune sera were analyzed by ELISA.

Results

The results demonstrated that the cationic liposome-mediated DNA immunization with an N:P charge ratio of 1:3 (anionic lipoplexes) is more effective than the use of naked plasmid DNA alone. No antibody response was observed when lipoplexes with a higher N:P charge ratio of 10:3 (cationic lipoplexes) were used. Trehalose was added to some lipoplex formulations as a cryoprotectant and adjuvant, but it did not yield any further improvement of immunogenicity in vivo.

Conclusions

The results suggest that Pfs25 plasmid DNA delivered as lipoplexes at a charge ratio of 1:3 elicited strong immunogenicity in mice and may be improved further to match the immune responses of DNA vaccines administered by in vivo electroporation.
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16.

Purpose

To establish a platform for the possibility of effective and safe delivery of Temozolomide (TMZ) to brain via surface engineered (polyamidoamine) PAMAM dendrimer for the treatment of glioblastoma.

Methods

The present study aims to investigate the efficacy of PAMAM-chitosan conjugate based TMZ nanoformulation (PCT) against gliomas in vitro as well as in vivo. The prepared nanoconjugated formulation was characterized by 1H NMR, FT-IR spectroscopy and for surface morphological parameters. The reported approach was also designed in such a way to ensure toxicity before in vivo delivery through conducting the hemolytic study.

Result

Surface morphology was found as per nanoformulation via size, pdi and zeta potential measurement. PCT was more efficacious in terms of IC50 values compared to pure TMZ against U-251 and T-98G glioma cell lines. The in vivo pharmacokinetic parameters proved sustained release fashion such as half-life (t1/2) of 22.74 h (PCT) rather than15.35 h (TMZ) only. Higher concentration was found in heart than brain in bio-distribution studies. This study exhibits the potential applicability of dendrimer and CS in improving the anticancer activity and delivery of TMZ to brain.

Conclusion

The attractive ex vivo cytotoxicity against two glioma cell lines; U-251 and T-98G and phase solubility studies of TMZ revealed remarkable results. In vivo studies of prepared nanoformulation were significant and promising that explored the double concentration of TMZ in brain due to surface functionality of dendrimer. The reported work is novel and non- obvious as none of such approaches using chitosan anchored dendrimer for TMZ delivery has been reported earlier.
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17.

Purpose

To test the hypothesis that a mixture combining fast and slower release rate microspheres can restore blood flow rapidly and prevent formation of another blockage in thrombolysis.

Methods

We used polyethylene glycol (PEG) microspheres which provide the release of the encapsulated streptokinase (SK) on the scale of minutes, and Eudragit FS30D (Eud), a polymethacrylate polymer, for development of delayed release microspheres which were desirable to prevent a putative second thrombus. Eud microspheres were coated with chitosan (CS) to further extend half-life. Experiments included the development, characterization of Eud/SK and CS-Eud/SK microspheres, and in vitro thrombolytic studies of the mixtures of PEG/SK and Eud /SK microspheres and of PEG/SK and CS-Eud/SK microspheres.

Results

CS-Eud/SK microspheres have slightly lower encapsulation efficiency, reduced activity of SK, and a much slower release of SK when compared with microspheres of Eud/SK microspheres. Counter-intuitively, slower release leads to faster thrombolysis after reocclusion as a result of greater retention of agent and the mechanism of distributed intraclot thrombolysis.

Conclusions

A mixture of PEG/SK and CS-Eud/SK microspheres could break up the blood clot rapidly while providing clot-lytic efficacy in prevention of a second blockage up to 4 h.
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18.

Purpose

To assess the gelation power of N-palmitoyl L-alanine derivatives in injectable oils and to use the best chosen organogel as parenteral implant of granisetron for the treatment of emesis.

Methods

Twelve N-palmitoyl L-alanine derived organogels were developed and evaluated in terms of morphology, thermal properties and in vivo performance. The ability of the selected formula to form in situ gel upon subcutaneous injection in rats and its biocompatibility were monitored over 2 weeks by histopathological examination of the injection site.

Results

The acid derivative (N-palmitoyl L-alanine; PA) was superior to ester derivatives. The chosen formula (PA/safflower oil 10% w/v) was successful in forming an in situ gel of granisetron when subcutaneously injected in rats, lasting for 2 weeks and proved to be biocompatible by histopathological examination. Moreover, it exerted an extended antiemetic activity by decreasing the cisplatin-induced pica for a duration of 96 h and reduced preprotachykinin A mRNA expression and Substance P level for up to 4 days (gastric tissue) or 5 days (medulla oblongata) in rats.

Conclusion

Granisetron organogel could be considered as a safe, sustained-release and supportive anticancer treatment in both acute and chronic emesis as well as an accompanying treatment with chemotherapeutics in cancer cases.
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19.

Purpose

To evaluate the combination of a pressure-indicating sensor film with hydrogel-forming microneedle arrays, as a method of feedback to confirm MN insertion in vivo.

Methods

Pilot in vitro insertion studies were conducted using a Texture Analyser to insert MN arrays, coupled with a pressure-indicating sensor film, at varying forces into excised neonatal porcine skin. In vivo studies involved twenty human volunteers, who self-applied two hydrogel-forming MN arrays, one with a pressure-indicating sensor film incorporated and one without. Optical coherence tomography was employed to measure the resulting penetration depth and colorimetric analysis to investigate the associated colour change of the pressure-indicating sensor film.

Results

Microneedle insertion was achieved in vitro at three different forces, demonstrating the colour change of the pressure-indicating sensor film upon application of increasing pressure. When self-applied in vivo, there was no significant difference in the microneedle penetration depth resulting from each type of array, with a mean depth of 237 μm recorded. When the pressure-indicating sensor film was present, a colour change occurred upon each application, providing evidence of insertion.

Conclusions

For the first time, this study shows how the incorporation of a simple, low-cost pressure-indicating sensor film can indicate microneedle insertion in vitro and in vivo, providing visual feedback to assure the user of correct application. Such a strategy may enhance usability of a microneedle device and, hence, assist in the future translation of the technology to widespread clinical use.
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20.

Purpose

The ability of two semi-mechanistic simulation approaches to predict the systemic pharmacokinetics (PK) of inhaled corticosteroids (ICSs) delivered via dry powder inhalers (DPIs) was assessed for mometasone furoate, budesonide and fluticasone propionate.

Methods

Both approaches derived the total lung doses and the central to peripheral lung deposition ratios from clinically relevant cascade impactor studies, but differed in the way the pulmonary absorption rate was derived. In approach 1, the rate of in vivo drug dissolution/absorption was predicted for the included ICSs from in vitro aerodynamic particle size distribution and in vitro drug solubility estimates measured in an in vivo predictive dissolution medium. Approach 2 derived a first order absorption rate from the mean dissolution time (MDT), determined for the test formulations in an in vitro Transwell® based dissolution system.

Results

Approach 1 suggested PK profiles which agreed well with the published pharmacokinetic profiles. Similarly, within approach 2, input parameters for the pulmonary absorption rate constant derived from dissolution rate experiments were able to reasonably predict the pharmacokinetic profiles published in literature.

Conclusion

Approach 1 utilizes more complex strategies for predicting the dissolution/absorption process without providing a significant advantage over approach 2 with regard to accuracy of in vivo predictions.
  相似文献   

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