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Updated: May 15, 2026

In Vivo Microdialysis Method to Collect Large Extracellular Proteins from Brain Interstitial Fluid with High-molecular Weight Cut-off Probes
Published on: September 26, 2018
In vivo brain microdialysis as a formulation-screening tool for a poorly soluble centrally acting drug
Murali Mohan Bommana1, Bharat Kirthivasan, Abhijat Shikhar
1Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University , Jamaica, NY , USA.
Objective:
Efficacy of a formulation of a poorly soluble centrally acting drug was evaluated by measuring dopamine responses using in vivo brain microdialysis.
Methods:
Co-crystals (1:1) of carbamazepine and nicotinamide (CBZ-NCT) were complexed with cyclodextrins (γ-CDs) using supercritical fluid processing. Phase solubility and intrinsic dissolution were studied. Pharmacodynamic studies were performed on rats divided into three groups getting either CBZ-NCT in CD (20 mg/kg CBZ), pure CBZ solution or vehicle. A guide cannula was implanted to attach the microdialysis probe. Dialysate samples were analyzed for dopamine levels, which were compared between groups.
Results:
The optimized CBZ formulation (5% w/w in γ-CD) with solubility - 10 mg/mL showed stepwise increase in dopamine response (maximum 250% of baseline) compared to neat CBZ or vehicle (p < 0.05). The pharmacokinetics of the drug required 30 min to elicit CNS response, which peaked at about 1.5-2 h.
Conclusion:
Hence, brain microdialysis was successfully used to evaluate a dissolution rate enhancing formulation.
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