CN107496998B

CN107496998B - Peripheral drug eluting stent and preparation and application thereof

Info

Publication number: CN107496998B
Application number: CN201710695391.7A
Authority: CN
Inventors: 周挺; 果艳东; 石培国; 胡堃; 赵艳
Original assignee: Beijing Yongyi Runcheng Technology Co ltd
Current assignee: Beijing Yongyi Runcheng Technology Co ltd
Priority date: 2017-08-15
Filing date: 2017-08-15
Publication date: 2020-12-08
Anticipated expiration: 2037-08-15
Also published as: CN107496998A

Abstract

The invention provides a peripheral drug eluting stent, wherein a drug coating of the peripheral drug eluting stent is divided into an outer drug sustained-release layer, a middle drug sustained-release mixed layer and an inner drug sustained-release mixed layer, wherein: the outer slow release layer has molecular weight of 30000, PLA: PGA 70: 30 PLGA; the intermediate drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 50: 50, PTX by mass ratio: PLGA ═ 3: 1; the inner drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 80: 20, PTX in mass ratio: PLGA ═ 3: 1. The invention also relates to the preparation and application of the peripheral drug eluting stent. The invention can effectively treat the peripheral vascular stenosis diseases; the problem of restenosis in the stent generated after the traditional peripheral metal bare stent is implanted into the peripheral blood vessel is avoided.

Description

Peripheral drug eluting stent and preparation and application thereof

Technical Field

The invention relates to a peripheral drug eluting stent and preparation and application thereof.

Background

The incidence of peripheral vascular disease has increased remarkably in recent years, and arteriosclerotic occlusion, arteriovenous thrombosis, and the like are common. At present, the professional technology for treating peripheral vascular diseases in China is developing vigorously, the traditional surgical technology is continuously perfected, and the application of the interventional therapy method in clinic is becoming wide. The clinical application of the self-expandable peripheral vascular stent is an important milestone for treating the peripheral vascular stenosis diseases. However, the problem of in-stent restenosis generated after many traditional peripheral metal bare stents are implanted into peripheral blood vessels is increasingly obvious. According to statistics, the middle and long term restenosis rate of the peripheral metal bare stent can reach 15-60 percent, and the curative effect of the peripheral intravascular stent implantation is seriously restricted.

The causes of restenosis in stents are mainly: after the stent is implanted, the peripheral blood vessel intima hyperplasia is caused. After the peripheral intravascular stent is implanted into a diseased blood vessel, mechanical injury of intima can be caused to different degrees, the body can actively repair the injured part, and the repairing mode is that the surface of the stent is covered by a new intima layer, and the excessive repairing process is usually an excessive repairing process, namely excessive hyperplasia. Research shows that 24 hours after the peripheral blood vessel internal stent is implanted, local inflammatory reaction can be caused in a metal bare stent, blood vessel smooth muscle cells begin to proliferate under stimulation, the smooth muscle cell proliferation reaches the most active stage after about 4 weeks, the proliferation can last for 3 months, and finally the peripheral blood vessel intimal hyperplasia is caused, so that the in-stent restenosis is generated.

With the wide application of a drug sustained-release stent system and the continuous development of new technology, a peripheral drug eluting stent is selected to replace a metal bare stent in the current peripheral vascular interventional therapy, but the current peripheral drug eluting stent has poor sustained-release effect, and a serious defect of drug release is 'burst release', namely, the drug release amount reaches about 70% within 24 hours after the stent is placed, and the effective drug concentration is obviously insufficient in the subsequent release period, thereby seriously affecting the curative effect of the peripheral drug eluting stent.

Disclosure of Invention

In view of the technical drawbacks and disadvantages of the prior art, embodiments of the present invention provide a peripheral drug eluting stent, a method of making the same, and applications thereof, that overcome or at least partially address the above-mentioned problems.

The invention provides a peripheral drug eluting stent, wherein a drug coating of the peripheral drug eluting stent is divided into an outer drug sustained-release layer, a middle drug sustained-release mixed layer and an inner drug sustained-release mixed layer, wherein:

the outer slow release layer is 30000 in molecular weight, polylactic acid (PLA): glycolic Acid (PGA) 70: 30 polylactic-co-glycolic acid (PLGA);

the intermediate drug sustained-release mixed layer is a mixture of Paclitaxel (PTX) and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 50: 50, PTX by mass ratio: PLGA ═ 3: 1;

the inner drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 80: 20, PTX in mass ratio: PLGA ═ 3: 1.

Specifically, the drug density of the drug coating layer is 3 micrograms per square millimeter, and the mass ratio of the PTX of the intermediate drug sustained-release mixed layer to the PTX of the inner drug sustained-release mixed layer is 1: 1, the mass ratio of PLGA of the outer layer slow release layer, the middle drug slow release mixed layer and the inner layer drug slow release mixed layer is 1: 1: 1.

specifically, the solvent for preparing the drug coating is tetrahydrofuran.

Specifically, the peripheral drug eluting stent is a nickel titanium stent.

The embodiment of the invention also relates to a method for preparing the peripheral drug eluting stent, which comprises the following steps:

weighing 10mg of molecular weight 30000, PLA: PGA 70: 30 ml of PLGA is added with 10ml of tetrahydrofuran, and the mixture is magnetically stirred for 30-60min to completely dissolve the polymer, so as to obtain outer layer slow-release layer spraying liquid;

weigh 30mg ptx and 10mg molecular weight 20000, PLA: PGA 50: adding 10ml of tetrahydrofuran into 50 ml of PLGA, and magnetically stirring for 30-60min to completely dissolve the polymer to obtain the intermediate drug slow-release mixed layer spraying solution;

weigh 30mg ptx and 10mg molecular weight 20000, PLA: PGA 80: adding 10ml of tetrahydrofuran into 20ml of PLGA, and magnetically stirring for 30-60min to completely dissolve the polymer to obtain the inner drug slow-release mixed layer spraying solution;

rinsing the polished bracket in acetone, absolute ethyl alcohol and purified water for 5-10 minutes in sequence respectively, and drying the cleaned bracket in a vacuum drying oven for later use;

and spraying the medicine coating spraying liquid to a bracket in an ultrasonic atomization spraying mode, wherein: the spraying cycle times of the spraying liquid of the inner drug slow-release mixing layer and the spraying liquid of the middle drug slow-release mixing layer are both 5 times, and the spraying cycle times of the spraying liquid of the outer drug slow-release mixing layer are 3 times.

Specifically, the method further includes: filtering the dissolved outer layer slow release layer spraying liquid, the middle drug slow release mixed layer spraying liquid and the inner layer drug slow release mixed layer spraying liquid by using a 0.22 mu m sterile filter before spraying.

Specifically, the method further includes: and (3) putting the sprayed stent into a vacuum drying oven, and drying for 30 minutes under the conditions that the vacuum degree is 0.8bar and the drying temperature is 38 ℃.

Specifically, the method further includes: the environment humidity of the ultrasonic atomization spraying process is controlled to be 20-25%, and the temperature is controlled to be 22-24 ℃.

Specifically, the method further includes: when the drug coating is sprayed to the stent by the ultrasonic atomization spraying mode, the spraying parameters of the ultrasonic atomization spraying machine are set as follows: the distance between the nozzle and the surface of the bracket is 6mm, the spraying air flow is 3L/min, the liquid medicine flow rate is 3L/min, the ultrasonic power is 2W, the axial moving speed of the spraying along the bracket is 10mm/s, and the rotating speed of the rotating shaft of the bracket is 200 r/min.

Specifically, the stent used in the method is a nickel titanium stent.

The invention also relates to the application of the peripheral drug eluting stent in peripheral vascular interventional therapy.

The outer, middle and inner drug coatings are sprayed on the peripheral drug eluting stent, the slow release material adopts PLGA, the drugs in the middle drug slow release mixing layer and the inner drug slow release mixing layer are released along with the degradation of the PLGA in the outer drug slow release layer, the middle drug slow release mixing layer and the inner drug slow release mixing layer, the drug release rate can be controlled, and early burst release can be prevented. The results of the PLGA in-vitro degradation behavior research show that: the PTX drug is released as the PLGA degrades, with the drug release rate at different time periods: the release rate detected by the test at the 1 st day is 5-20%, the release rate detected by the test at the 7 th day is 15-40%, the release rate detected by the test at the 14 th day is 30-60%, the release rate detected by the test at the 28 th day is 50-80%, and the release rate detected by the test at the 90 th day is more than 80%. The existing research results show that: after the intravascular stent is placed in the operation, smooth muscle cells begin to proliferate for 24 hours, and the smooth muscle cell proliferation is most active around week 4 and can last for 3 months. The PLGA of the peripheral drug eluting stent has higher degradation speed in 2 to 6 weeks, the release speed of the carried drug is increased, and the PLGA can play a stronger drug role when the smooth muscle cell proliferation is most active, which shows that the PLGA slow release material controlled release drug rule adopted by the invention is adapted to the time window of the intimal hyperplasia, so that the intimal hyperplasia can be better inhibited, and the purpose of preventing the restenosis in the stent can be achieved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

FIG. 1 is the in vitro release results for the peripheral drug eluting stent of example 1;

FIG. 2 is the in vitro release results for the peripheral drug eluting stent of example 2;

FIG. 3 is the in vitro release results for the peripheral drug eluting stent of example 3;

FIG. 4 is the in vitro release results for the peripheral drug eluting stent of example 4;

FIG. 5 is the in vitro release results for the peripheral drug eluting stent of example 5;

FIG. 6 is the in vitro release results for the peripheral drug eluting stent of example 6;

figure 7 is the in vitro release results for the peripheral drug eluting stent of example 7.

Detailed Description

Exemplary embodiments of the present disclosure are described in more detail below. While this section shows exemplary embodiments of the disclosure, it should be understood that the disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In order to explain the technical means of the present invention, the following description will be given by way of specific examples.

The embodiment of the invention adopts a nickel titanium bare stent. The outer diameter of the nickel-titanium bare stent is 8mm, and the length of the nickel-titanium bare stent is 80 mm; the medicament in the medicament coating spraying liquid is PTX; the slow release material is PLGA; tetrahydrofuran is adopted as a solvent.

Example 1

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 1, 2, 3 are specifically prepared as follows:

preparation of spraying liquid medicine of the stent 1:

preparing the outer-layer medicament of the medicament stent: weighing 10mgPLGA (molecular weight 30000, PLA: PGA 70: 30), adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

drug preparation of the middle layer of the drug stent: weighing 20mg PTX and 10mg PLGA (molecular weight 20000, PLA: PGA is 50: 50), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

drug stent inner layer drug configuration: 20mg of PTX and 10mg of PLGA (molecular weight 20000, PLA: PGA: 80: 20) were weighed, 10ml of tetrahydrofuran was added, and the mixture was magnetically stirred for 30 to 60min to completely dissolve the polymer.

Preparation of spraying liquid medicine for the stent 2:

drug preparation of the middle layer of the drug stent: weighing 30mg PTX and 10mg PLGA (molecular weight 20000, PLA: PGA is 50: 50), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

drug stent inner layer drug configuration: 30mg of PTX and 10mg of PLGA (molecular weight 20000, PLA: PGA: 80: 20) were weighed, 10ml of tetrahydrofuran was added, and the mixture was magnetically stirred for 30 to 60min to completely dissolve the polymer.

Preparation of spraying liquid medicine for the stent 3:

drug preparation of the middle layer of the drug stent: weighing 40mg PTX and 10mg PLGA (molecular weight 20000, PLA: PGA is 50: 50), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

drug stent inner layer drug configuration: 40mg of PTX and 10mg of PLGA (molecular weight 20000, PLA: PGA: 80: 20) were weighed, 10ml of tetrahydrofuran was added, and the mixture was magnetically stirred for 30 to 60min to completely dissolve the polymer.

Respectively filtering the spraying liquid medicine of the three-layer medicine coating of the 3 metal stents by using a sterile filter with the diameter of 0.22 mu m, and spraying the filtered liquid medicine by using SONO-TEK BCC-300 type ultrasonic atomization spraying equipment according to the following spraying process parameters: the specification of the peripheral drug stent is that the outer diameter is 8mm, the length is 80mm, the distance between a nozzle and the surface of the stent is 6mm, the spraying air flow is 3L/min, the flow rate of liquid medicine is 3L/min, the ultrasonic power is 2W, the axial moving speed of the spraying along the stent is 10mm/s, the rotating speed of a rotating shaft of the stent is 200r/min, the inner-layer drug is firstly sprayed, the spraying cycle is 5 times, the middle-layer drug is then sprayed, the spraying cycle is 5 times, and finally the outer-layer drug is sprayed, and the spraying cycle is.

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, the peripheral drug eluting stents 1, 2 and 3 are respectively obtained.

Example 2

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 4, 5, 6 are specifically prepared as follows:

preparation of spraying liquid medicine for the stent 4:

preparing the outer-layer medicament of the medicament stent: weighing 10mg PLGA (molecular weight 20000, PLA: PGA 70: 30), adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

Preparation of spraying liquid medicine for the bracket 5:

Preparation of spraying liquid medicine for the bracket 6:

preparing the outer-layer medicament of the medicament stent: weighing 10mgPLGA (molecular weight 40000, PLA: PGA 70: 30), adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, the peripheral drug eluting stents 4, 5 and 6 are respectively obtained.

Example 3

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 7, 8, 9 are specifically prepared as follows:

preparation of spraying liquid medicine for the stent 7:

Preparation of spraying liquid medicine for the stent 8:

drug preparation of the middle layer of the drug stent: weighing 30mgPTX and 10mgPLGA (molecular weight 30000, PLA: PGA is 50: 50), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

Preparation of spraying liquid medicine for the stent 9:

drug preparation of the middle layer of the drug stent: weighing 30mgPTX and 10mgPLGA (molecular weight 40000, PLA: PGA is 50: 50), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, peripheral drug eluting stents 7, 8 and 9 are respectively obtained.

Example 4

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 10, 11, 12 are specifically prepared as follows:

preparation of spraying liquid medicine for the stent 10:

Preparation of spraying liquid medicine for the stent 11:

drug stent inner layer drug configuration: 30mg PTX and 10mg PLGA (molecular weight 30000, PLA: PGA: 80: 20) were weighed, 10ml tetrahydrofuran was added, and the mixture was magnetically stirred for 30-60min to completely dissolve the polymer.

Preparation of spraying liquid medicine for the stent 12:

drug stent inner layer drug configuration: 30mg of PTX and 10mg of PLGA (molecular weight 40000, PLA: PGA: 80: 20) were weighed, 10ml of tetrahydrofuran was added, and the mixture was magnetically stirred for 30 to 60min to completely dissolve the polymer.

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, peripheral drug eluting stents 10, 11, 12 are obtained respectively.

Example 5

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 13, 14, 15 are specifically prepared as follows:

preparation of spraying liquid medicine for the stent 13:

Preparation of spraying liquid medicine for the stent 14:

preparing the outer-layer medicament of the medicament stent: weighing 10mgPLGA (molecular weight 30000, PLA: PGA 50: 50), adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

Preparation of spraying liquid medicine for the stent 15:

preparing the outer-layer medicament of the medicament stent: weighing 10mgPLGA (molecular weight 30000, PLA: PGA 80: 20), adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, peripheral drug eluting stents 13, 14, 15 are obtained, respectively.

Example 6

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 16, 17, 18 are specifically prepared as follows:

preparation of spraying liquid medicine for the stent 16:

drug preparation of the middle layer of the drug stent: weighing 30mg PTX and 10mg PLGA (molecular weight 20000, PLA: PGA 70: 30), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

Preparation of spraying liquid medicine for the stent 17:

Preparation of spraying liquid medicine for the stent 18:

drug preparation of the middle layer of the drug stent: weighing 30mg PTX and 10mg PLGA (molecular weight 20000, PLA: PGA: 80: 20), respectively adding 10ml tetrahydrofuran, and magnetically stirring for 30-60min to completely dissolve the polymer;

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, peripheral drug eluting stents 16, 17, 18 are obtained, respectively.

Example 7

Three peripheral medicine elution stents that this embodiment provided, three layers of drug coating are sprayed respectively to the outside of three naked stents of metal. The peripheral vascular stents 19, 20, 21 are specifically prepared as follows:

preparation of spraying liquid medicine for the stent 19:

drug stent inner layer drug configuration: 30mg of PTX and 10mg of PLGA (molecular weight 20000, PLA: PGA: 70: 30) were weighed, 10ml of tetrahydrofuran was added, and the mixture was magnetically stirred for 30 to 60min to completely dissolve the polymer.

Preparation of spraying liquid medicine for the stent 20:

drug stent inner layer drug configuration: 30mg of PTX and 10mg of PLGA (molecular weight 20000, PLA: PGA: 50) were weighed, 10ml of tetrahydrofuran was added, and the mixture was magnetically stirred for 30 to 60min to completely dissolve the polymer.

Preparation of spraying liquid medicine for the stent 21:

And (3) putting the sprayed 3 supports into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃. Finally, peripheral drug eluting stents 19, 20, 21 are obtained, respectively.

Example 8

Method for measuring paclitaxel in vitro release rate

Test conditions

The chromatographic column was C18 (4.6X 250mm, 5 μm), the detection wavelength was 227nm, the sample size was 10 μ l, the flow rate was 1.0ml/min, the column temperature was 45 ℃ and the mobile phase acetonitrile-water ratio was 60: 40.

Standard solution preparation

Accurately weighing paclitaxel about 20mg by weight loss method with a precision electronic balance, placing in a 100ml volumetric flask, dissolving with chromatographic pure acetonitrile, diluting to scale, and shaking. Using acetonitrile as solvent to prepare 1-100 mug/ml standard solution of paclitaxel as testing solution.

Determination of Standard Curve

The above solution was diluted with chromatographically pure acetonitrile to 5 control solutions ranging from 1. mu.g/ml to 100. mu.g/ml. And respectively injecting samples according to the chromatographic conditions. And performing linear regression by taking the concentration of the paclitaxel reference substance as a vertical coordinate and taking the corresponding peak area as a horizontal coordinate to obtain a regression equation, and calculating a correlation coefficient. The sample concentration was calculated from the standard curve.

Release method

The scaffolds were vertically fixed in brown graduated stoppered tubes, 20ml of a release medium containing 76% (v/v) acetonitrile and 24% water was added to each scaffold, sealed, and shaken at constant temperature of 100rpm at 37 ℃. The stent is taken out after 1, 7, 14, 28 and 90 days respectively, and is put into a brown dissolution cup filled with 20ml of fresh release medium for continuous slow release. Taking 1ml of the sustained-release solution to be detected, adding 1ml of acetonitrile, uniformly mixing in a vortex mixer, filtering by using a 0.45-micron organic filter membrane, taking the subsequent filtrate, injecting into a liquid chromatograph, and recording the retention time and the peak area.

Calculation of results

Substituting the peak area of the sample into the standard curve according to the standard curve prepared by the standard solution, and calculating the content of the paclitaxel. The in vitro release rate (Rt,%) was calculated according to the following formula:

wherein Wt is the amount of drug released at different times (t) and W0 is the nominal amount of drug in the stent.

The in vitro release curves of the drug-eluting stents prepared by the methods of examples 1 to 7 were determined according to the above-mentioned paclitaxel in vitro release rate determination method, and are shown in fig. 1 to 7.

Referring to fig. 1, the slow release curves of the peripheral drug eluting stents 1, 2 and 3 show that the drug release period of the stent 2 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted by the metal stent, and the stent has better slow release effect than the stent 1 and the stent 2, can well inhibit the intimal hyperplasia of the peripheral blood vessel, and achieves the purpose of preventing restenosis in the stent.

Referring to fig. 2, the slow release curves of the peripheral drug eluting stents 4, 5 and 6 show that the drug release period of the stent 5 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted by the metal stent, and the slow release effect is better than that of the stent 4 and the stent 6, so that the intimal hyperplasia of the peripheral blood vessel can be well inhibited, and the purpose of preventing restenosis in the stent can be achieved.

Referring to fig. 3, it can be seen from the slow release curves of the peripheral drug eluting stents 7, 8, 9 that the drug release period of the stent 7 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted with the metal stent, and the stent has better slow release effect than the stent 8 and the stent 9, and can well inhibit the intimal hyperplasia of the peripheral blood vessel, thereby achieving the purpose of preventing restenosis in the stent.

Referring to fig. 4, it can be seen from the slow release curves of the peripheral drug eluting stents 10, 11, 12 that the drug release period of the stent 10 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted with the metal stent, and the stent has better slow release effect than the stent 11 and the stent 12, and can well inhibit the intimal hyperplasia of the peripheral blood vessel, thereby achieving the purpose of preventing restenosis in the stent.

Referring to fig. 5, it can be seen from the slow release curves of the peripheral drug eluting stents 13, 14, 15 that the drug release period of the stent 13 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted with the metal stent, and the stent has better slow release effect than the stent 14 and the stent 15, and can well inhibit the intimal hyperplasia of the peripheral blood vessel, thereby achieving the purpose of preventing restenosis in the stent.

Referring to fig. 6, it can be seen from the slow release curves of the peripheral drug eluting stents 16, 17, 18 that the drug release period of the stent 17 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted with the metal stent, and the stent has better slow release effect than the stent 16 and the stent 18, and can well inhibit the intimal hyperplasia of the peripheral blood vessel, thereby achieving the purpose of preventing restenosis in the stent.

Referring to fig. 7, it can be seen from the slow release curves of the peripheral drug eluting stents 19, 20, 21 that the drug release period of the stent 21 is adapted to the intimal hyperplasia time of the peripheral blood vessel implanted with the metal stent, and the stent has better slow release effect than the stent 19 and the stent 20, and can well inhibit the intimal hyperplasia of the peripheral blood vessel, thereby achieving the purpose of preventing restenosis in the stent.

The peripheral drug-eluting stents 2, 5, 7, 10, 13, 17, 21 of examples 1-7 all gave the best release results in comparative experiments, and thus, it can be seen that the drug coating layer of the peripheral drug-eluting stent is divided into an outer drug-eluting layer, an intermediate drug-eluting mixed layer and an inner drug-eluting mixed layer, wherein: the outer slow release layer has a molecular weight of 30000, and PLA: PGA 70: 30 PLGA; the intermediate drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 50: 50, PTX by mass ratio: PLGA ═ 3: 1; the inner drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 80: 20, PTX in mass ratio: when PLGA is 3:1, the optimal effect of inhibiting intimal hyperplasia in peripheral blood vessels can be achieved, thereby preventing restenosis.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. The utility model provides a periphery medicine elution support, its characterized in that, periphery medicine elution support's medicine coating divide into outer layer slowly-releasing layer, middle medicine slowly-releasing mixed layer and inlayer medicine slowly-releasing mixed layer, wherein:

the outer slow release layer has a molecular weight of 30000, and PLA: PGA 70: 30 PLGA;

the intermediate drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 50: 50, PTX by mass ratio: PLGA ═ 3: 1;

the inner drug sustained-release mixed layer is a mixture of PTX and PLGA, wherein the molecular weight of PLGA is 20000, and the weight ratio of PLA: PGA 80: 20, PTX in mass ratio: PLGA ═ 3: 1;

the drug density of the drug coating is 3 micrograms/square millimeter, and the mass ratio of the PTX of the middle drug slow-release mixed layer to the PTX of the inner drug slow-release mixed layer is 1: 1;

the mass ratio of PLGA of the outer layer slow release layer, the middle drug slow release mixed layer and the inner layer drug slow release mixed layer is 1: 1: 1.

2. the peripheral drug-eluting stent of claim 1, wherein the drug coating is formulated with tetrahydrofuran as a solvent.

3. The peripheral drug-eluting stent of claim 1, wherein the peripheral drug-eluting stent is a nickel titanium stent.

4. A method of making a peripheral drug eluting stent according to any of claims 1-3, comprising the steps of:

weighing 30000 molecular weight, PLA: PGA 70: 30, adding tetrahydrofuran into the PLGA, and magnetically stirring to completely dissolve the polymer to obtain an outer-layer slow-release layer spraying liquid;

weighing PTX and molecular weight 20000, PLA: PGA 50: 50 parts of PLGA, adding tetrahydrofuran, and magnetically stirring to completely dissolve the polymer to obtain an intermediate drug slow-release mixed layer spraying solution;

weighing PTX and molecular weight 20000, PLA: PGA 80: 20, adding tetrahydrofuran into the PLGA, and magnetically stirring to completely dissolve the polymer to obtain the inner drug slow-release mixed layer spraying solution;

5. The method as recited in claim 4, further comprising: filtering the dissolved outer layer slow release layer spraying liquid, the middle drug slow release mixed layer spraying liquid and the inner layer drug slow release mixed layer spraying liquid by using a 0.22 mu m sterile filter before spraying.

6. The method of claim 4 or 5, further comprising: and (3) putting the sprayed stent into a vacuum drying oven, and drying for 30 minutes at the vacuum degree of 0.8bar and the drying temperature of 38 ℃.

7. The method of claim 6, wherein the humidity of the environment during the ultrasonic spray is controlled to be 20-25% and the temperature is controlled to be 22-24 ℃.

8. The method of claim 6, wherein when the drug coating is applied to the stent by ultrasonic spray, the spray parameters of the ultrasonic spray applicator are set as: the distance between the nozzle and the surface of the bracket is 6mm, the spraying air flow is 3L/min, the liquid medicine flow rate is 3L/min, the ultrasonic power is 2W, the axial moving speed of the spraying along the bracket is 10mm/s, and the rotating speed of the rotating shaft of the bracket is 200 r/min.

9. Use of a peripheral drug eluting stent according to any of claims 1-3 in a peripheral vascular interventional treatment device.