Short duration depot formulations

a depot and formulation technology, applied in the field of depot gel compositions, can solve the problems of reluctance of patients to accept such an implant or drug delivery system, important limitations of their use in the body of various animals, and materials that do not always meet the demand for biodegradable implants

Inactive Publication Date: 2006-07-27
DURECT CORP
View PDF98 Cites 53 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0014] The present invention provides a method and an injectable depot gel composition for systemic and local delivery of a beneficial agent to a subject over a short duration of time. In particular, the invention provides controlled release of the beneficial agent to the subject being treated, the release being controlled over a period equal to or less than two weeks after administration, prefereably a period of about 3 to about 7 days. Additionally, the invention provides a method of preparing the injectable depot gel composition.

Problems solved by technology

Although thermoplastic and thermosetting biodegradable polymers have many useful biomedical applications, there are several important limitations to their use in the bodies of various animals including humans, animals, birds, fish, and reptiles.
Such implants have to be inserted into the body through an incision which is sometimes larger than desired by the medical profession and occasionally lead to a reluctance of the patients to accept such an implant or drug delivery system.
However, these materials do not always satisfy the demand for a biodegradable implant.
These materials are particulate in nature, do not form a continuous film or solid implant with the structural integrity needed for certain prostheses, the particles tend to aggregate and thus their behavior is hard to predict.
When inserted into certain body cavities such as a mouth, a periodontal pocket, the eye, or the vagina where there is considerable fluid flow, these small particles, microspheres, or microcapsules are poorly retained because of their small size and discontinuous nature.
Further, if there are complications, removal of microcapsule or small-particle systems from the body without extensive surgical intervention is considerably more difficult than with solid implants.
Additionally, manufacture, storage and injectability of microspheres or microcapsules prepared from these polymers and containing drugs for release into the body present problems.
Rapid migration of water into such polymeric implants utilizing water soluble polymer solvents when the implants are placed in the body and exposed to aqueous body fluids presents a serious problem.
The rapid water uptake often results in implants having pore structures that are non-homogeneous in size and shape.
The rapid water uptake characteristic often results in uncontrolled release of beneficial agent that is manifested by an initial, rapid release of beneficial agent from the polymer composition, corresponding to a “burst” of beneficial agent being released from the implant.
Such an effect can be unacceptable, particularly in those circumstances where a controlled delivery is desired, i.e., delivery of beneficial agent in a controlled manner over a period of greater than or equal to 3 days or up to a month, or where there is a narrow therapeutic window and release of excess beneficial agent can result in adverse consequences to the subject being treated, or where it is necessary to mimic the naturally-occurring daily profile of beneficial agents, such as hormones and the like, in the body of the subject being treated.
Accordingly, when such devices are implanted, the finger-like pores allow very rapid uptake of aqueous body fluids into the interior of the implant with consequent immediate and rapid dissolution of significant quantities of beneficial agent and unimpeded diffusion of beneficial agent into the environment of use, producing the burst effect discussed above.
Furthermore, rapid water uptake can result in premature polymer precipitation such that a hardened implant or one with a hardened skin is produced.
That lag time is undesirable from the standpoint of presenting a controlled, sustained release of beneficial agent to the subject being treated.
Notwithstanding some success, those methods have not been entirely satisfactory for the large number of beneficial agents that would be effectively delivered by implants.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Short duration depot formulations
  • Short duration depot formulations
  • Short duration depot formulations

Examples

Experimental program
Comparison scheme
Effect test

example 1

Depot Gel Preparation

[0151] A gel vehicle for use in an injectable depot of the composition was prepared as follows. A glass vessel was tared on a Mettler PJ3000 top loader balance. Poly (D,L-lactide-co-glycolide) (PLGA), available as 50:50 DL-PLG with an inherent viscosity of 0.15 (PLGA-BPI, Birmingham Polymers, Inc., Birmingham, Ala.) and 50:50 Resomer® R RG502 (PLGA RG 502), was weighed into the glass vessel. The glass vessel containing the polymer was tared and the corresponding solvent was added. Amounts expressed as percentages for various polymer / solvent combinations are set forth in Table 1, below. The polymer / solvent mixture was stirred at 250±50 rpm (IKA electric stirrer, IKH-Werke GmbH and Co., Stanfen, Germany) for about 5-10 minutes, resulting in a sticky paste-like substance containing polymer particles. The vessel containing the polymer / solvent mixture was sealed and placed in a temperature controlled incubator equilibrated to 37° C. for 1 to 4 days, with intermitten...

example 2

hGH Particle Preparation

[0153] Human growth hormone (hGH) particles (optionally containing zinc acetate) were prepared as follows: hGH solution (5 mg / ml) solution in water (BresaGen Corporation, Adelaide, Australia) was concentrated to 10 mg / mL using a Concentration / Dialysis Selector diafiltering apparatus. The diafiltered hGH solution was washed with 5 times volume of tris or phosphate buffer solution (pH 7.6). Particles of hGH were then formed by spray drying or lyophilization using conventional techniques. Phosphate buffer solutions (5 or 50 mM) containing hGH (5 mg / mL) (and optionally various levels of zinc acetate (0 to 30 mM) when Zn complexed particles were prepared) were spray-dried using a Yamato Mini Spray dryer set at the following parameters:

Spray Dryer ParameterSettingAtomizing Air2 psiInlet Temperature120° C.Aspirator Dial7.5Solution Pump2-4Main Air Valve40-45 psi

[0154] hGH particles having a size range between 2-100 microns were obtained. Lyophilized particles were...

example 3

hGH-Stearic Acid Particle Preparation

[0155] Human growth hormone (hGH) particles were prepared as follows: Lyophilized hGH (3.22 grams, Pharmacia-Upjohn, Stockholm, Sweden) and stearic acid (3.22 grams, 95% pure, Sigma-Aldrich Corporation, St. Louis, Mo.) were blended and ground. The ground material was compressed in a 13 mm round die, with a force of 10,000 pounds for 5 minutes. Compressed tablets were ground and sieved through a 70 mesh screen followed by a 400 mesh screen to obtain particles having a size range between 38-212 microns.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
miscibilityaaaaaaaaaa
wt. %aaaaaaaaaa
timeaaaaaaaaaa
Login to view more

Abstract

Methods and compositions for systemically or locally administering by implantation a beneficial agent to a subject are described, and include, for example, depot gel compositions that can be injected into a desired location and which can provide controlled release of a beneficial agent over a short duration of time. The compositions include a low molecular weight biocompatible polymer, a biocompatible solvent having low water miscibility that forms a viscous gel with the polymer and limits water uptake by the implant, and a beneficial agent.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a divisional of U.S. application Ser. No. 10 / 606,969, filed Jun. 25, 2003, entitled “SHORT DURATION DEPOT FORMULATIONS” which claims the benefit of U.S. Provisional Application No. 60 / 391,867, filed on Jun. 24, 2002. The contents of the above referenced applications are hereby incorporated in their entirety by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a depot gel composition that can be injected into a desired location and which can provide controlled release of a beneficial agent over a short duration of time. The present invention also relates to a method of preparing and administering the composition. [0004] 2. Description of the Related Art [0005] Biodegradable polymers have been used for many years in medical applications. Illustrative devices composed of the biodegradable polymers include sutures, surgical clips, staples, implants, and drug del...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(United States)
IPC IPC(8): A61K9/14A61K9/00A61K9/22A61K47/10A61K47/14
CPCA61K9/0014A61K9/0019A61K9/0024A61K47/10A61K47/14A61K31/445A61K38/27A61P23/00A61P23/02A61K9/08A61K9/06A61K47/34
Inventor CHEN, GUOHUAPRIEBE, DAVID
Owner DURECT CORP
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products