Example 1
In order to prepare a PLLA mixture, first, PLLA (poly-L-lactic acid) having a molecular weight of about 150,000 kDa (kilodaltons) was prepared. CMC (carboxymethylcellulose) and mannitol were mixed with the PLLA, followed by freeze-drying. At this time, the freeze-drying was carried out by primary freeze-drying at −60 to −100° C. for 12 to 24 hours and secondary drying at 15 to 25° C. for 5 to 10 days.
The freeze-dried PLLA mixture was pulverized to a size ranging from 30 μm to 100 μm (appropriately 50 μm) using an overhead stirrer, and was subjected to gamma-ray sterilization to prepare a PLLA mixture powder.
Example 2
A multiple emulsion of water in oil in water (W/O/W) was prepared by the following two-step procedure.
A 5 mM phosphate buffer solution in which a drug containing a pain reliever and/or antibiotic is dissolved in a concentration of 5 mg/ml was mixed with a primary core material (W1), the PLLA mixture prepared in Example 1, a biodegradable polymer, an MCT (medium-chain triglyceride) oil and PGPR (polyglycerol polyricinoleate) as an emulsifier, followed by stirring to obtain an oily phase (O), and the oily phase was homogenized to prepare a W1/O emulsion as a primary emulsion.
In order to prepare a W/O/W emulsion, a secondary wall material (W2) for encapsulating the W1/O emulsion was prepared as follows.
First, HA having a molecular weight of about 2 million kDa was mixed with BDDE (butanediol diglycidyl ether) as a crosslinking agent at a predetermined ratio, and the gelled HA was washed with a phosphate buffer. The phosphate buffer was used in an amount of 30 to 80 liters (appropriately 50 liters) with respect to 100 grams of HA.
The washed HA was passed through a screen with 80 to 120 mesh having a uniform size to obtain crosslinked HA with uniform particles. In this case, the optimal screen hole size may be 100 mesh.
Distilled water was added to the crosslinked HA and was then mixed at 9,400 rpm using a homogenizer for 5 minutes. This material was further homogenized at 14,000 rpm using a homogenizer for 5 minutes to obtain a secondary wall material (W2).
Then, 25% (w/w) of the W1/O emulsion was mixed with 75% (w/w) of the secondary wall material (W2), followed by stirring at 400 rpm in a stirrer for 5 minutes and homogenization using a homogenizer (5 minutes, 20,000 rpm) to prepare a PLLA-HA W/O/W emulsion.
Example 3
A microcapsule as a powder was prepared from the W/O/W emulsion prepared in Example 2 using a spray dryer (Eyela spray-dryer SD-1000, Eyela, Tokyo, Japan). Specifically, the temperature of the fed air was adjusted to 130±5° C., the discharge air temperature was adjusted to 80±5° C., the rotary sprayer was adjusted to 10×10 kPa, the blower speed was adjusted to 0.80 m3/min, and the pump speed was adjusted to 1.0 mL/min.
The double microcapsule prepared through the above process was injected into a vial and then gamma-ray sterilized once more and frozen at −20° C.
The present invention is characterized in that the double microencapsulated PLLA-HA W/O/W emulsion can be used immediately after injecting injection water into the same. Specifically, when preparing a filler for the face, 15 to 25 ml of distilled water was mixed with 10 mg of the double microcapsule, whereas when preparing a filler for the body, to 35 cc of distilled water was mixed with 10 mg of double microcapsule.
The double microencapsulated PLLA-HA W/O/W emulsion was completely micronized and homogenized during the preparation process, thereby solving conventional problems in which it is required to form a suspension and allow the suspension to stand for 2 hours or longer before use after mixing water for injection, and particles of PLLA agglomerate in the composition.
As described above, the present invention is characterized in that the long time taken to form initial volume during injection, which is the disadvantage of conventional PLLA filler products (e.g., products such as Sculptra), can be shortened by 6-8 weeks or more, and the present invention is based on a combination with cross-linked hyaluronic acid in order to minimize the formation of granuloma, which is another disadvantage of conventional PLLA fillers, and the aggregation of PLLA is significantly reduced even after insufficient mixing time or long-term storage by producing the same into fine particles.
Further, the sustained-release double microcapsule of the present invention is in a form in which a pain reliever or antibiotic is contained in PLLA as a biodegradable polymer particle, and is characterized by continuously releasing the pain reliever as it is decomposed in the body, thereby solving problems related to pain and infection that may be caused by filler treatment.
The description of the present invention is provided only for illustration, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. For example, a component described as a single unit may be implemented in a separated manner, and similarly, components described as being separated may also be implemented in a combined form.
The scope of the present invention is defined by the claims to be set forth below, and all alterations or modifications derived from the meanings and scopes of the claims and equivalents thereto should be construed as falling within the scope of the present invention.
