Peramivir Dry Powder Inhaler and Method of Preparing the Same

Abstract

Disclosed is a peramivir dry powder inhaler, comprising a peramivir API or its acceptable salt or hydrate, wherein a single-dose preparation has a content of 5˜30 mg; the particle size distribution D10 of the dry powder is 1.3˜2.2 μm, D50 is 3˜6 μm, and D90 is 6˜13 μm. The peramivir dry powder inhaler prepared can effectively lower the titer of the influenza A virus in mouse lungs, has a notable anti-virus effect, can significantly prolong survival time and reduce mortality rate. The drug efficacy of the peramivir dry powder inhaler is superior to those of the peramivir sodium chloride injection and oseltamivir phosphate. The peramivir dry powder inhaler has a specific lung targeting effect, with notable improvement in drug effectiveness and safety.

Claims

1. A peramivir dry powder inhaler, comprising: dry powder of a peramivir active pharmaceutical ingredient API or an acceptable salt or hydrate of the peramivir API, wherein a dry powder loading capacity of a single-dose preparation ranges from 5 to 30 mg; and particle size distribution D10 of the dry powder ranges from 1.3 μm to 3 μm, particle size distribution D50 of the dry powder ranges from 3 μm to 6 μm, and particle size distribution D90 of the dry powder ranges from 6 to 13 μm.

2. The peramivir dry powder inhaler according to claim 1, wherein the dry powder has an angle of repose ranging from 33° to 37°, preferably 34°, 35°, 36°; a bulk density of 0.23˜0.28 g/cm.sup.3, preferably 0.24, 0.25, 0.26, 0.27 g/cm.sup.3; and a tapped density of 0.39˜0.44 g/cm.sup.3, preferably 0.40, 0.41, 0.42, 0.43 g/cm.sup.3.

3. The peramivir dry powder inhaler according to claim 1, wherein the Carr's flowability index of the dry powder ranges from 58 to 65, preferably 59, 60, 61, 62.

4. The peramivir dry powder inhaler according to claim 1, wherein the percentage of the dry powder with a fine powder fraction FPF less than 4.46 μm is greater than 30% and less than 45%, preferably 32%, 33%, 34%, 35%, 36%, 37%, 38%, 40%, 41%, more preferably ranging from 34% to 38%.

5. The peramivir dry powder inhaler according to claim 1, wherein the dry powder has an aerodynamic particle size greater than 2.5 μm and less than 3.6 μm, preferably ranging from 2.8 μm to 3.5 μm or from 2.6 μm to 3.1 μm or from 2.9 μm to 3.4 μm, and more preferably from 3.0 μm to 3.2 μm or from 3.1 μm to 3.3 μm.

6. The peramivir dry powder inhaler according to claim 1, wherein the particle size distribution D10 of the dry powder ranges from 1.3 μm to 2.0 μm, preferably 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.1 μm; the particle size distribution D50 is preferably 3.5 μm, 4.5 μm, 5 μm, 5.5 μm; and the particle size distribution D90 is preferably 6.2 μm, 6.5 μm, 7 μm, 7.5 μm, 7.8 μm, 8.0 μm, 8.4 μm, 9.0 μm, 10 μm, 11 μm, 12 μm.

7. The peramivir dry powder inhaler according to claim 1, wherein the dry powder inhaler is prepared by a peramivir trihydrate.

8. A peramivir dry powder inhaler preparation, wherein the dry powder according to claim 1 is prepared into a capsule dosage form, a niosome dosage form, or a depot dosage form, wherein a dry powder loading capacity of each unit of dosage form ranges from 5 to 30 mg, preferably 20 mg.

9. A method of preparing the peramivir dry powder inhaler according to claim 1, comprising: jet milling a peramivir trihydrate at a feed pressure 0.4˜0.55 MPa and a milling pressure 0.4˜0.6 MPa, whereby to obtain a dry powder.

Description

DETAILED DESCRIPTION

[0035] Hereinafter, the present disclosure will be further described with reference to the accompanying drawings. It is understood that the embodiments provided herein are only intended for illustrating the present application, not intended for limiting the scope of the present disclosure. The experiment methods without setting forth specific conditions in the embodiments follow conventional conditions or those recommended by manufacturers.

[0036] Unless otherwise defined, all professional and scientific terminologies used herein have meanings familiar to those skilled in the art. In addition, any method and material similar or equivalent to the contents disclosed herein may be applied to the method of the present disclosure. The preferred implementation methods and materials are only for illustrative purposes.

[0037] The present disclosure involves the following determination methods:

[0038] 1. determining the angle of repose, comprising: determining the angle of repose by a fixed funnel method, wherein the drug powder flew out from the funnel at a predetermined velocity; then the diameter (D) and height (h) of the piled powder were measured, wherein r=D/2; then the angle of repose was calculated according to the equation tan a=h/r.

[0039] 2. determining the bulk density and tapped density, comprising: uniformly transferring the drug powder into a measuring cylinder and tapping the drug powder therein 100 times, wherein the pre-tapping drug weight and volume and the post-tapping drug weight and volume were recorded.

[0040] 3. determining the particle size of the powder, comprising: placing the drug powder on a laser particle size analyzer to measure its particle size.

[0041] D.sub.g and aerodynamic particle size D.sub.a: the median particle size (D.sub.g) was measured; the aerodynamic diameter (D.sub.a, MMAD) was calculated according to the equation:

[00001]$D_a=D_g\sqrt{\frac{\rho }{{\rho }_0𝓍}}.$

1. Example 1

[0042] The peramivir spray dry powder formulations were set forth below:

TABLE-US-00001 TABLE 1 Peramivir Spray Dry Powder Formulations Ingredients Composition 1 Composition 2 peramivir  6 g  6 g  leucine 0 600 mg phospholipid 0 120 mg ultrapure water 120 ml 120 ml

[0043] Process conditions: the parameters of spray drying process were as such: inlet temperature 200° C., outlet temperature 100° C., and velocity: 400 ml/h. The resulting powder was sieved through a 180-mesh sieve. The experiment results were set forth below:

TABLE-US-00002 TABLE 2 Experiment Results of Peramivir Spray Dry Powder (n = 3) Indexes Composition 1 Composition 2 ρbulk density(g/cm.sup.3) 0.080 0.08 ρtapped density(g/cm.sup.3) 0.144 0.14 median particle size D.sub.g (μm) 3.29 2.99 aerodynamic particle size D.sub.a (μm) 1.25 1.12 angle of repose α(°) 38.81 44.86
The experiment results show that after the formulation was optimized by adding phospholipid and amid acid, the density and particle size of the spray dry powder were diminished, but flowability was deteriorated.

[0044] 2. The spray dry powder was blended with mannitol to obtain a dry powder blend, wherein the peramivir spray dry powder prepared according to composition 1 was sufficiently blended with the mannitol in proportions of: 1:1; 1:2; 1:5 (w/w). The experiment results are set forth below:

TABLE-US-00003 TABLE 3 Experiment Results of the Peramivir Spray Powder and Mannitol Blends(n = 3) Com- Com- position Com- position 1: Com- position 1: position 1: Mannitol Mannitol Mannitol Indexes 1 (1:1) (1:2) (1:5) ρbulk 0.080 0.140 0.224 0.313 density (g/cm.sup.3) ρtapped density 0.144 0.144 0.293 0.322 (g/cm.sup.3) median particle size 3.29 3.693 4.732 8.457 D.sub.g (μm) aerodynamic particle 1.25 2.000 2.650 5.733 size D.sub.a (μm) angle of repose α(°) 38.81 33.62 29.40 31.54
The experiment results show that after the peramivir dry powder was blended with mannitol, the flowability improves although the particle size and density increase prominently.

[0045] 3. The spray dry powder was blended with lactose to obtain a dry powder blend, wherein the peramivir spray dry powder of compositions 1 was blended with lactose in a proportion of 1:1 (w/w).

TABLE-US-00004 TABLE 4 Experiment Results of the Peramivir Spray Dry Powder and Lactose Blend (n = 3) Composition 1: Indexes Composition 1 Lactose (1:1) ρbulk density (g/cm.sup.3) 0.080 0.15 ρtapped density (g/cm.sup.3) 0.144 0.32 median particle sizeD.sub.g(μm) 3.29 6.07 aerodynamic particle sizeD.sub.a(μm) 1.25 2.05 angle of repose α (°) 38.81 44.0
The experiment results show that after the dried powder was blended with lactose (1:1, w/w), its density and particle size increased, but its flowability was deteriorated.

[0046] It was also found in the experiment that the electrostatic adsorption between spray dried powder particles increased, such that the dry powder was easily agglomerated. Therefore, the spray dried peramivir powder was not suitable for being prepared into a dry powder inhaler, and this situation is not improved even after blending with lactose.

2. Example 2

[0047] Formulation 1: peramivir dry micropowder, which was prepared by jet milling peramivir active pharmaceutical ingredient (API) under the following conditions: feed rate 130V, feed pressure 0.45 MPa, and milling pressure 0.45 MPa.

[0048] Formulation 2: the dry powder resulting from Formulation 1 was blended with lactose Inhalac 120 in a mass ratio of 1:1 to obtain a powder blend.

[0049] Formulation 3: the dry powder resulting from Formulation 1 was blended with lactose Inhalac 400 in a mass ratio of 1:1 to obtain a powder blend.

Pulmonary Deposition Ratio Experiment

[0050] The powders resulting from Formulations 1 to 3 were loaded into capsules, respectively, 20 mg for each capsule. Before starting the experiment, the NGI (Next Generation Pharmaceutical Impactor) was closed and an induction port was installed and tightly sealed with a seal film. The experiment procedure comprised: first turning on the pump, turning on the flow meter, turning on the TPK (critical flow controller) instrument; then connecting the flow meter to the induction port, loading empty capsules and punching holes through the capsules with a pen-type drug delivery device, and connecting the pen-type drug delivery device to the flow meter to measure the flow rate. Parameters of the DPI particle size distribution analyzer were set as such: Flow=60; P3=14.4; P2=66.8. The number of sample capsules fed was set to 20, and the feed duration was set to 7 seconds. Then, an adaptor was installed to the induction port. The drug-loaded capsules were connected to the inhaler device of the drug particle size distribution analyzer; and then the inhalation button was clicked; the above operations were repeated twenty times. After the 20 capsules were completely inhaled, the drug powder inhaled in the collection trays of the induction port, stage 1, stage 2, stage 3, and stage 4 was rinsed twice with 10 ml deionized water, respectively; the rinsed water was then transferred into a 50 ml volumetric flask; meanwhile, the inhaler device and the induction port were rinsed with ultrapure water, and the rinsed water was collected into a volumetric flask, respectively. The drug powder inhaled in the collection trays of stage 6, stage 7, and stage 8 of the NGI was rinsed twice with 10 ml deionized water, respectively; the rinsed ultrapure water was transferred in a 25 ml volumetric flask. Finally, the fine particle fraction (FPF) of each formulation was measured. The results are set forth below:

TABLE-US-00005 TABLE 5 Fine Particle Fraction (n = 3) Result Formulation 1 Formulation 2 Formulation 3 FPF, <4.46 μm 31.32 ± 0.02 33.97 ± 2.99 13.97 ± 0.06

TABLE-US-00006 TABLE 6 Distribution of the Powder in Various Stages of the NGI (n = 3) Mean Content (mg) NGI Stages Formulation 1 Formulation 2 Formulation 3 Stage 1 62.70 91.79 74.90 Stage 2 32.14 35.64 41.32 Stage 3 32.45 30.71 22.88 Stage 4 31.76 31.93 15.00 Stage 5 24.90 55.34 8.29 Stage 6 13.95 14.26 2.81 Stage 7 3.59 6.12 0.81 Stage 8 3.25 3.97 0.62 Inhaler Device 118.90 109.96 21.39 Induction Port 16.92 27.61 168.27 Total 340.56 407.33 356.29

[0051] In terms of FPF, formulation 1 is approximate to formulation 2, but formulation 3 has a much smaller FPF, which is approximate to 10% of the criteria provided in the pharmacopoeia. The particles in formulation 3 were mainly stuck at the induction port, a possible cause of which is that too fine lactose particles easily produce static. It is seen that formulation 3 is not suitable as a peramivir dry powder formulation.

Stability Experiment

[0052] Capsules with formulations 1 and 2 were placed for 0 days, 5 days, and 10 days under 60° C., respectively, to observe appearance change of the blends and measure the following indexes:

[0053] (1) Delivered Dose Uniformity (DDU)

[0054] Capsules with formulations 1 and 2 were connected to a DDU device, wherein the sample loaded in each capsule had a content of 20 mg; the pump was turned on, the flow meter was connected to a collection tube, wherein one end of the collection tube was placed with filter paper, and the other end thereof was connected to the flow meter; a DUSA (Dosage Unit Sampling Apparatus) collection tube was connected to the flow meter; and empty capsules were loaded and punched with holes with the pen-type drug delivery device to measure the flow rate. The TPK (critical flow controller) instrument was turned on; the Set Up button on the TPK instrument was pressed to set parameters; after the parameters were set, the “OK” button was pressed, and then the “set P1” button was pressed to adjust the flow rate to 60 L/min. The “set flow” button was pressed, and when the screen displays flow (Q), the “Yes” button was pressed; and then the “Yes” button was pressed again; the readings on the screen were recorded, and then the flow meter was removed. The DDU parameters were set as such: Flow=60; P3=14.4; P2=66.8. The drug-loaded capsules were placed in an inhaler device manufactured by Suzhou Wantong; the inhalation button was clicked, with 1 capsule being inhaled each time. The medicine on the filter paper and in the collection tube was rinsed with ultrapure water into a 50 ml beaker; the beaker was rinsed three times, and the collected liquid was transferred into a 50 ml volumetric flask, and then ultrapure water was dripped into the flask to bring to volume. 10 parts of collected liquid were subjected to HPLC detection to determine the content of drug in each part of the collected liquid.

[0055] (2) Fine Particle Fraction (FPF<4.46 μm), which was measured by NGI.

TABLE-US-00007 TABLE 7 Experiment Results of DPI Stability under High Temperature (60° C.) results Day 0 Day 5 Day 10 FPF < Delivered FPF < Delivered FPF < Delivered formulations Appearance 4.46 μm dose % appearance 4.46 μm dose % appearance 4.46 μm dose % Formulation White 27.18 ± 0.03  99.99 ± 16.02 White 27.63 ± 0.16 100.02 ± 10.82 White 26.00 ± 0.59 105.54 ± 13.30 1 powder powder powder Formulation White 32.37 ± 2.82 101.82 ± 16.87 White 21.82 ± 0.08 105.70 ± 22.88 White 18.43 ± 0.27 100.05 ± 2.40  2 powder powder powder

[0056] The above table shows the delivered doses of different formulations under different influencing factors, wherein the samples (20 mg per capsule) were manually loaded and accurately quantified. The results show that the delivered doses meet the criteria (mean value between 75% and 125%) specified in the pharmacopeia, and high temperature does not affect the DDU much.

[0057] The fine particle fraction (FPF<4.46 μm) results show that the high temperature does not affect the FPF of formulation 1 much, but affects the FPF of formulation 2 much. Therefore, additive-free, carrier-free peramivir is the optimal formulation, while blend with excipients and carriers does not lead to performance improvement.

Example 3

[0058] A 1.3 kg peramivir trihydrate API was milled with a jet mill to obtain a dry powder under feed rate 130V, inlet pressure 0.45 Mpa, and milling pressure 0.40 MPa; the dry powder was loaded into HPMC (Hydroxypropyl Methyl Cellulose) capsules, 20 mg for each capsule, wherein the particle size distribution D10 of the dry powder was 1.934 μm, D50 was 4.415 μm, and D90 was 8.858 μm; the angle of repose was 34.8°; the bulk density was 0.25 g/cm.sup.3, the tapped density was 0.41 g/cm.sup.3, and the Carr's index was 59.0.

Example 4

[0059] A 1.3 kg peramivir trihydrate ingredient was milled with a jet mill to obtain a dry powder under feed rate 125V, inlet pressure 0.50 Mpa, and milling pressure 0.45 MPa; the dry powder was loaded into HPMC (Hydroxypropyl Methyl Cellulose) capsules, 20 mg for each capsule, wherein the particle size distribution D10 of the dry powder was 1.447 μm, D50 was 3.269 μm, and D90 was 6.988 μm. The results showed that the angle of repose was 35.3°, the bulk density was 0.26 g/cm.sup.3, the tapped density was 0.43 g/cm.sup.3, and the Carr's index was 60.0.

Example 5

[0060] A 1.3 kg peramivir trihydrate ingredient was milled with a jet mill to obtain a dry powder under feed rate 135V, inlet pressure 0.42 Mpa, and milling pressure 0.40 MPa; the dry powder was loaded into HPMC (Hydroxypropyl Methyl Cellulose) capsules, 20 mg for each capsule, wherein the particle size distribution D10 of the dry powder was 2.034 μm, D50 was 5.716 μm, and D90 was 12.67 μm. The results showed that the angle of repose was 34.1°, the bulk density was 0.23 g/cm.sup.3, the tapped density was 0.39 g/cm.sup.3, and the Carr's index was 61.0.

Example 6

[0061] A 1.3 kg peramivir trihydrate ingredient was milled with a jet mill to obtain a dry powder under feed rate 140V, inlet pressure 0.40 Mpa, and milling pressure 0.35 MPa; the dry powder was loaded into HPMC (Hydroxypropyl Methyl Cellulose) capsules, 15 mg for each capsule, wherein the particle size distribution D10 of the dry powder was 2.89 μm, D50 was 7.78 μm, and D90 was 16.39 μm. The results showed that the angle of repose was 33.7°, the bulk density was 0.24 g/cm.sup.3, the tapped density was 0.41 g/cm.sup.3, and the Carr's index was 65.0.

Example 7

[0062] A 1.3 kg peramivir trihydrate ingredient was milled with a jet mill to obtain a dry powder under feed rate 120V, inlet pressure 0.60 Mpa, and milling pressure 0.40 MPa; the dry powder was loaded into HPMC (Hydroxypropyl Methyl Cellulose) capsules, 15 mg for each capsule, wherein the particle size distribution D10 of the dry powder was 1.332 μm, D50 was 3.015 μm, and D90 was 5.658 μm. The results showed that the angle of repose was 38.4°, the bulk density was 0.28 g/cm.sup.3, the tapped density was 0.47 g/cm.sup.3, and the Carr's index was 66.0.

Experiment Example 1

Inhaled Powder NGI Delivery Experiment

[0063] 1. Preparing Samples

[0064] The dry powder sample obtained from Example 1 was subjected to NGI delivery test to measure its in vitro deposition ratio. The sample was filled in single-dose capsules. The test was performed three times, 10 capsules delivered each time.

[0065] 2. NGI Test Results

[0066] Upon completion of the NGI delivery test, the sample in each reception cup/sample tray of the NGI was rinsed, respectively; the rinsed water was collected into a volumetric flask and brought to volume; and then the content was measured using the HPLC method.

TABLE-US-00008 TABLE 8 In Vitro Deposition Ratio Test Results of Example 1 Batch No. Example 3 Number of Samples under Test 10 capsules per time Number of Times of Testing 3 times Flow Rate 60 L/min Distribution of Samples at Software Calculation Results of NGI Various Stages of NGI Delivery In Vitro Deposition Ratio Inhaler Device 17.83% Metered(mg) 20.689 Induction Port 32.86% Delivered Dose (mg) 16.998 Preseparator  9.43% Fine particle dose (mg)  6.129 Stage 1  3.75% FPF(%) 36.038 Stage 2  8.62% MMAD(um)  3.271 Stage 3 11.37% GSD  1.961 Stage 4  8.58% R{circumflex over ( )}2  0.993 Stage 5  3.72% Stage 6  2.02% Stage 7  1.14% MOC (Micro-Orifice  0.66% Collector) Stages 2-7 35.46% Stages 3-7 26.84%

Experiment Example 2

Comparative Experiment on In Vitro Deposition Ratios of Different Particle Sizes

[0067] The samples obtained from Examples 1 to 4 were subjected to NGI in vitro deposition ratio test. The testing results are set forth below:

TABLE-US-00009 TABLE 9 Results of NGI In Vitro Deposition Ratio Test on Different Particle Sizes Batch No. Example 3 Example 4 Example 5 Example 6 Number of 10 capsules 10 capsules 10 capsules 10 capsules Samples under per time per time per time per time Test Number of 3 3 3 3 Testing Flow Rate 60 L/min 60 L/min 60 L/min 60 L/min Inhaler Device 17.84% 24.89% 17.86% 18.97% Induction Port 32.86% 18.12% 40.94% 55.37% Preseparator  9.43%  9.19%  8.32%  9.56% Stage 1  4.05%  2.57%  3.19%  4.93% Stage 2  8.62%  8.20%  6.78%  5.01% Stage 3 11.37% 13.30%  8.75%  4.12% Stage 4  8.58% 14.24%  8.19%  1.35% Stage 5  3.72%  6.47%  3.71%  0.43% Stage 6  2.02%  2.16%  1.58%  0.11% Stage 7  1.14% 21.38%  0.49%  0.09% MOC  0.66%  0.26%  0.20%  0.06% Stages 2~7 35.46% 65.76% 29.50% 11.17% Stages 3~7 26.84% 57.56% 22.71%  6.16%

[0068] The in vitro deposition ratio of samples with a particle size D90 greater than 12.67 μm can hardly meet the criteria specified in the pharmacopeia (which requires a fine particle dose not less than 10%), while Example 2 provides a good in vitro deposition ratio.

Experiment Example 3

Stability Experiment

[0069] The dry powder obtained from Example 1 was exposed to high-temperature (60° C.) and sampled on day 0, day 5, day 10, and day 30 to test their NGI in vitro deposition ratio.

TABLE-US-00010 TABLE 10 Stability Experiment on the Dry Powder of Example 1 under High Temperature (60° C.) Starting Items under sample Capsule Batch No. Test Day 0 Day 5 Day 10 Day 30 Sample 1 Metered(mg) 20.689 20.309 21.608 21.695 Delivered(mg) 16.998 16.179 16.488 17.378 Fine Particle 6.129 6.306 6.473 5.780 Dose(mg) FPF(%) 36.038 38.978 39.219 33.274 MMAD(μm) 3.271 3.451 3.496 3.182 GSD 1.961 1.945 1.893 2.007 R{circumflex over ( )}2 0.993 0.995 0.999 0.980 Stage 1  3.75%  4.44%  4.02%  3.35% Stage 2  8.62% 10.60% 10.59%  7.60% Stage 3 11.37% 12.05% 12.01%  9.51% Stage 4  8.58%  8.87%  9.46%  6.84% Stage 5  3.72%  3.64%  3.85%  3.32% Stage 6  2.02%  2.02%  1.29%  2.55% Stage 7  1.14%  1.12%  0.43%  1.53% Stage 8  0.65%  0.74%  0.26%  1.02% Induction Port 32.86% 28.24% 26.54% 35.98% Inhaler Device 17.83% 20.35% 23.69% 19.90% Preseparator  9.43%  7.94%  7.85%  8.42% Deposition 26.84% 27.70% 27.04%  23.7% Ratios of Stages 3~7 Deposition 35.46% 38.30% 37.64%  31.3% Ratios of Stages 2~7
The experiment results show that the dry powder inhaler according to the present disclosure has a superb stability at a high temperature.

Experiment Example 4

In Vivo Protection of Nebulized Peramivir Dry Powder Inhaler Administered to Mice Infected With Influenza A/Pr/8/34 Virus

[0070] 80 SPF Balb/c mice, half male and half female, weighing 16.9˜22.6 g each, were stochastically divided into 8 groups: a normal control group, a virus model group, an oseltamivir phosphate capsule group (Tamiflu) (10 mg/kg), a peramivir intravenous injection group (10 mg/kg), and peramivir dry powder inhaler (example 3) groups I-IV (0.1, 0.3, 0.9, 2.7 mg/kg), ten mice in each group. The mice in each group were mildly anaesthetized with diethyl ether and intranasally administered with influenza A/PA/8/34 virus liquid (5 LD.sub.50 diluted solution resulting from diluting the influenza virus bulk with a 4° C. precooled blank culture medium), 60 μL per mouse, wherein the normal control group was intranasally administered with the blank culture medium of the same volume. Prior to daily administration, the peramivir intravenous injection was prepared into a 1.0 mg/mL liquor with 0.9% sodium chloride injection, and the oseltamivir phosphate capsule was prepared into a 0.5 mg/mL liquor with pure water. The mice in each group were all administered at 2 h post-modeling of the intranasal virus infection, wherein the mice in each peramivir dry powder inhaler group were administered with a corresponding dosage of peramivir dry powder inhaler, the mice in the peramivir intravenous injection group were intravenously injected with the peramivir liquid as per a dosage of 10 mL/kg, the oseltamivir phosphate capsule group were intragastrically administered with oseltamivir phosphate liquid as per a dosage of 20 mL/kg, and the normal control group and the model control group were sprayed with air of the same volume via their trachea. The mice were administered once per day, 5 days in succession. The first day (D1) of virus infection was counted from the next day of the intranasal virus inflection modeling.

[0071] Starting from the day of infection modeling, the mice were observed for 15 days successively to record the weights, death time, and number of deaths of the mice in each group, so as to measure weight changes during the administration period and calculate the morality rate (=number of dead mice/total number of mice×100%) and the average survival time (=total number of survival days of the mice/number of mice).

TABLE-US-00011 TABLE 11 Protective Effect of Peramivir Against Death of Mice Infected with Influenza A/PR/834 Virus (x ± s) Average number of Dosage Number of Number of Number of Mortality survival Group # (mg/kg) mice deaths survivals rate (%) days Normal / 10 0 10  0 15.0 ± 0.0 control group Virus / 10 10 0 100.sup.++  6.2 ± 1.0.sup.++ control group Oseltamivir 10 10 4 6  40** 11.3 ± 4.8* phosphate   group   Peramivir 10 10 3 7  30** 12.3 ± 4.4** I.V.   injection   group   Peramivir 0.1 10 7 3  70  8.7 ± 4.4 DPI group I   Peramivir 0.3 10 5 5  50** 10.4 ± 4.9 DPI group II   Peramivir 0.9 10 2 8  20** 13.2 ± 3.8** DPI group   III   Peramivir 2.7 10 1 9  10** 14.0 ± 3.2** DPI group V Compared with the normal control group, .sup.++P ≤ 0.01; compared with the virus control group, *P ≤ 0.05, **P ≤ 0.01.

[0072] As shown in Table 11, during the experiment period, the mice in the normal control group were not infected by virus such that no death occurred thereto; while 10 mice in total were dead in the 10-mice virus control group, the mortality rate amounting to 100%, which attained a significant statistical difference (P≤0.01) over the normal control group. Compared with the virus control group, the mortality rates of the mice in the oseltamivir phosphate group, the peramivir intravenous injection (I.V.) group, and the peramivir DPI groups II-IV were significantly decreased (P≤0.05 or P≤0.01); while the peramivir DPI group I had no statistical significance (P>0.05) compared with the virus control group. Compared with the normal control group, the average number of survival days of the mice in the virus control group is 6.2, which is significantly decreased (P≤0.01). Compared with the virus control group, the average survival time of peramivir DPI groups I and II was prolonged to a certain extent, but they had no statistical difference (P>0.05). The average survival time of the oseltamivir phosphate group, the peramivir I.V. injection group, and the peramivir DPI groups III-IV were significantly prolonged (P≤0.05 or P≤0.01) over the virus control group.

[0073] The analysis of the results above shows that administration of the peramivir DPI at 2 h post-infection can significantly prolong the survival time and lower the mortality rate, which has a notable in vivo protective action and a notable dose-effect relationship. Meanwhile, the drug efficacy of the 0.9 mg/kg peramivir DPI was superior to that of the peramivir sodium chloride injection (10 mg/kg) and the oseltamivir phosphate capsule (10 mg/kg).

Experiment 5

[0074] Impact of Nebulized Administration of Peramivir DPI on Pulmonary System Virus Titer of Mice Inflected with Influenza A/PR/8/34 Virus

[0075] 84 SPF Balb/c mice, half male and half female, weighing 21.2˜26.6 g each, were stochastically divided into 7 groups: a normal control group, a virus model group, an oseltamivir phosphate capsule group (Tamiflu) (10 mg/kg), a peramivir I.V. group (10 mg/kg), and peramivir dry powder inhaler (example 3) groups I-III (0.1, 0.3, 0.9 mg/kg), twelve mice in each group (in each group, F04˜F06 and M04˜M06 were subjected to 24 h hemagglutination titer measurement, and F01˜F03 and M1˜M03 were subjected to 48 h hemagglutination titer measurement). The mice in each group were mildly anaesthetized with diethyl ether and intranasally administered with influenza A/PA/8/34 virus liquid (5 LD.sub.50 diluted solution resulting from diluting the influenza virus bulk with a 4° C. precooled blank culture medium), 60 μL per mouse, wherein the normal control group was intranasally administered with the blank culture medium of the same volume. Prior to daily administration, the peramivir I.V. injection was prepared into a 1.0 mg/mL liquor with 0.9% sodium chloride injection, and the oseltamivir phosphate capsule was prepared into a 0.5 mg/mL liquor with pure water. The mice in each group were all administered at 2 h post-modeling of the intranasal virus infection, wherein the mice in each peramivir DPI group were administered with a corresponding dosage of peramivir dry powder inhaler, the mice in the peramivir intravenous injection group were intravenously injected with the peramivir liquid as per a dosage of 10 mL/kg, the oseltamivir phosphate capsule group were intragastrically administered with oseltamivir phosphate liquid as per a dosage of 20 mL/kg, and the normal control group and the model control group were sprayed with air of the same volume via their trachea. The mice were administered once per day, 2 days in succession.

[0076] 6 mice, half male and half female, were stochastically selected from each group at 24 h and 48 h post-administration, respectively. The mice were euthanized by cervical dislocation and their lungs were procured through dissection and then put in a homogenizer. 0.9% sodium chloride injection was added according to a ratio of the lung weight (g) to 0.9% sodium chloride injection (mL)=1:9, followed by grinding the homogenates into mouse lung suspensions. The mouse lung suspensions were subjected to centrifugation at 2500 rpm for 20 min under a 4° C. environment, with the supernatant being acquired for future use. Except the first column, 50 μL PBS (Phosphate Buffer Saline) was added into hemagglutination plate wells. 100 μL to-be-tested supernatant was added into each well in the first column, respectively, followed by adding with serial dilution till the wells in the 11.sup.th column, and then 50 μL 0.5% chicken erythrocyte was added into each well, respectively, followed by setting for 40 min; the hemagglutination plate was then tilted to observe whether the erythrocyte flew in a teardrop shape. The hemagglutination titer was represented by a logarithmic value of the maximum dilution factor completely inducing coagulation of the chicken erythrocyte, wherein the higher the hemagglutination titer, the higher the titer of the virus in the mouse lung suspension.

TABLE-US-00012 TABLE 12 Impact of Peramivir DPI on Viral Titer of Mouse Lung Tissue Infected with Influenza A/PR/8/34 Virus ( X ± S , n = 6) Dosage hemagglutination titer Group # (mg/kg) 24 h 48 h Normal control group / 0.0 ± 0.0 0.0 ± 0.0 Virus control group / 4.7 ± 1.2.sup.++ 5.8 ± 1.2.sup.++ Oseltamivir phosphate group 10 2.5 ± 0.5** 2.2 ± 0.8** Peramivir I.V. injection 10 2.2 ± 1.0** 1.5 ± 0.5** group Peramivir DPI group I 0.1 3.2 ± 0.8** 2.5 ± 0.8** Peramivir DPI group II 0.3 1.8 ± 1.2** 1.7 ± 0.8** Peramivir DPI group III 0.9 1.3 ± 0.5** 1.2 ± 0.4** Note: compared with the normal control group .sup.++P < 0.01; compared with the virus control group, **P ≤ 0.01

[0077] As shown in Table 12, the mice in the normal control group were not infected by the virus such that their hemagglutination titers were 0. Compared with the normal control group, the lung hemagglutination titer of the virus control group were notably increased (P≤0.01) at 24 h and 48 h post-infection. Compared with the virus control group, the lung hemagglutination titers of the oseltamivir phosphate group, the peramivir I.V. injection group, and the peramivir inhaler groups I˜III were all notably decreased (P≤0.01) at 24 h and 48 h post-infection. The results showed that administration of peramivir DPI at 2 h post-infection can effectively decrease the titer of the influenza A virus in the lungs of mice, indicating that it has a significant antivirus effect and a notable dose-effect relationship; meanwhile, the drug efficacy of the 0.9 mg/kg peramivir DPI was superior to that of the peramivir sodium chloride injection (10 mg/kg) and the oseltamivir phosphate capsule (10 mg/kg).

[0078] What have been described above are only preferred embodiments of the present disclosure, not intended for limiting the substantive scope of the present disclosure. The substantive technical content of the present disclosure is broadly defined in the appended claims. Any technical entity or method accomplished by others with a completely identical scope as defined in the appended claims is an equivalent modification to the present disclosure, which shall fall into the scope of the appended claims of the disclosure.