In vivo evaluation of biodegradable progesterone microspheres in mares.

The research study focuses on developing an effective delivery system for progesterone, a hormone that plays a key role in equine fertility, using biodegradable progesterone microspheres which can maintain therapeutic levels over an extended period without causing the health issues associated with previously used methods.

Progesterone and its Role in Equine Fertility

Progesterone is a hormone that regulates the reproductive cycle and fertility. In veterinary medicine, progesterone is used to synchronize estrous behavior and prevent pregnancy loss in mares. The traditional treatment involves periodic intramuscular injections of the hormone. However, this method leads to adverse effects such as abscesses, inflammation, infections, scarring, and pain at the injection site. The research aims to develop an alternative treatment mode that will be less distressing for the animals.

Introduction of Polymeric Microspheres

Polymeric microspheres are being researched as a delivery method for a range of therapeutic agents, including progesterone. These microspheres allow the drug to be released by diffusion through the mass of the sphere or the erosion of the sphere matrix. However, several compounds, including progesterone, do not diffuse well through the carrier matrix, so a high surface-to-volume ratio is preferred. The researchers in this study use a solvent-extraction-precipitation technique to create microspheres with a high surface area.

Detailed Research Methodology

• Materials used in the research were of high quality, including micronized progesterone, poly l-lactide (PLA), and various chemicals for the preparation and testing of the microspheres.
• The researchers used a specific procedure to create the progesterone/PLA microspheres, which included using a combination of chemicals to disperse, solidify, collect, and dry the microspheres.
• The microspheres were characterized according to their size and total drug content. Additionally, they were screened for microbial contamination, ensuring they were safe for use.

Objective of the Study

The researchers aim to create a delivery system that maintains progesterone serum levels from 2 to 6 ng/ml for 10 to 14 days following intramuscular administration in mares. By doing so, the study hopes to offer a reliable, effective, and less distressing way of administering progesterone to mares. The researchers also compared the effects of this new method with the traditional dosing strategy used in ovariectomized and/or anovulatory mares.