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Mucoadhesive temperature-mediated in situ gel formulations using chitosan and hydroxyl propyl methyl cellulose were used to enhance intranasal (i.n.) delivery of the dopamine D2 agonist ropinirole to the brain. Formulations were tested for gelation time, thermosensitivity, mucoadhesion, in vitro release and permeation, in vitro cytotoxicity, nasal clearance, in vivo bioavailability and brain uptake. In vivo bioavailability and brain uptake of ropinirole were assessed in albino rats following intranasal administration of 99mTc-ropinirole in situ gel, intranasal ropinirole solution and intravenous (i.v.) ropinirole solution. Radiolabeled ropinirole uptake was calculated as a fraction of administered dose. The absolute bioavailabilty of ropinirole from the temperature-mediated in situ gelling nasal formulation was 82%. The AUC (0-480 min) in brain after nasal administration of ropinirole in situ gel was 8.5 times (869 +/- 250% x min/g versus 102 +/- 20% x min/g) that obtained following i.v. administration, this value was also considerably higher (869 +/- 250% x min/g versus 281 +/- 52% x min/g) than that achieved with intranasal ropinirole solution. High brain direct drug transport percentage (DTP; 90.36%) and drug targeting index (DTI) > 1 confirms direct nose to brain transport of the intranasal in situ gel formulation of ropinirole.

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This study reports the development and evaluation of Carbamazepine (CMP)-loaded microemulsions (CMPME) for intranasal delivery in the treatment of epilepsy. The CMPME was prepared by the spontaneous emulsification method and characterized for physicochemical parameters. All formulations were radiolabeled with 99m Tc (technetium) and biodistribution of CMP in the brain was investigated using Swiss albino rats. Brain scintigraphy imaging in rats was also performed to determine the uptake of the CMP into the brain. CMPME were found crystal clear and stable with average globule size of 34.11 ± 1.41 nm. Tc-labeled CMP solution (CMPS)/CMPME/CMP mucoadhesive microemulsion (CMPMME) were found to be stable and suitable for in vivo studies. Brain/blood ratio at all sampling points up to 8 h following intranasal administration of CMPMME compared to intravenous CMPME was found to be 2-to 3-fold higher signifying larger extent of distribution of the CMP in brain. Drug targeting efficiency and direct drug transport were found to be highest for CMPMME post-intranasal administration compared to intravenous CMP. Rat brain scintigraphy also demonstrated higher intranasal uptake of the CMP into the brain. This investigation demonstrates a prompt and larger extent of transport of CMP into the brain through intranasal CMPMME, which may prove beneficial for treatment of epilepsy.