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Preparation and biopharmaceutical evaluation of microcapsules of ampicillin
Abstract:
Microencapsulation of ampicillin, an orally administered antibiotic, with different viscosity grades of ethyl cellulose was studied. The preparation of microcapsules was done as follows; the mixture of ethyl cellulose-CH2Cl2-ampicillin was dispersed in purified water containing 0.5% (w/w) sodium lauryl benzenesulfonate, and then CH2Cl2 was dried out by elevating the temperature. The dissolution curves for the release of ampicillin from microcapsules prepared using the four different viscosity grades of ethyl cellulose were quite different. The release of ampicillin increased with decreasing ethyl cellulose viscosity. The evaluation of prepared microcapsules was made using gastric-emptying-controlled rabbits. The plasma concentration of ampicillin obtained by the administration of microcapsules showed a significant sustained-release pattern. The area under the plasma concentration curve (AUC) of ampicillin obtained after a single oral administration of microcapsules prepared using 10 cps ethyl cellulose was 1.8 times greater than that obtained after double oral administration of powder. This fact will be caused by the delaying of gastric-emptying, intestinal-transit and dissolution of ampicillin there. It was confirmed that a large number of microcapsules still remained in the stomach and each microcapsules still contained ampicillin at 24 h after dosing from the experiment using gastric-emptying-controlled rabbits.
Insights
Microencapsulation of ampicillin using ethyl cellulose enhances its oral delivery. Lower viscosity ethyl cellulose microcapsules provide sustained release, improving antibiotic bioavailability and gastric residence time.
Area of Science:
- Pharmaceutical Sciences
- Drug Delivery Systems
- Materials Science
Background:
- Ampicillin is an orally administered antibiotic with variable bioavailability.
- Developing effective oral drug delivery systems is crucial for improving therapeutic outcomes.
- Ethyl cellulose is a biocompatible polymer suitable for microencapsulation.
Purpose of the Study:
- To investigate the effect of ethyl cellulose viscosity on ampicillin microcapsule properties.
- To evaluate the in vivo performance of ampicillin microcapsules in a sustained-release context.
- To assess the impact of microencapsulation on ampicillin's pharmacokinetic profile.
Main Methods:
- Microencapsulation of ampicillin using four different viscosity grades of ethyl cellulose.
- Preparation involved dispersing an ethyl cellulose-CH2Cl2-ampicillin mixture in an aqueous solution.
- In vivo evaluation using gastric-emptying-controlled rabbits to determine plasma concentrations and gastric retention.
Main Results:
- Dissolution rates of ampicillin varied significantly with ethyl cellulose viscosity, increasing as viscosity decreased.
- Microcapsules demonstrated a significant sustained-release pattern in vivo.
- Area under the plasma concentration curve (AUC) was 1.8 times higher with 10 cps ethyl cellulose microcapsules compared to oral powder.
- Significant gastric retention of ampicillin microcapsules was observed up to 24 hours post-administration.
Conclusions:
- Ethyl cellulose viscosity critically influences ampicillin release from microcapsules.
- Microencapsulation with ethyl cellulose effectively delays gastric emptying and intestinal transit, enhancing ampicillin's oral bioavailability.
- This formulation strategy offers a promising approach for sustained oral delivery of ampicillin.