Objective: To synthesize β cyclodextrin nanosponges using a novel and efficient microwave mediated method for enhancing bioavailability of Rilpivirine HCl (RLP). Significance: Belonging to BCS class II RLP has pH dependent solubility and poor oral bioavailability. However, a fatty meal enhances its absorption hence the therapy indicates that the dosage form be consumed with a meal. But then it becomes tedious and inconvenient to continue the therapy for years with having to face the associated gastric side effects such as nausea. Method: Microwave synthesizer was used to mediate the poly-condensation reaction between β-cyclodextrin and cross-linker diphenylcarbonate. Critical parameters selected were polymer to cross-linker ratio, Watt power, reaction time and solvent volume. Characterization studies were performed using FTIR, DSC, SEM, ¹H-NMR and PXRD. Molecular modeling was applied to confirm the possibility of drug entrapment. In vitro drug dissolution followed by oral bioavailability studies was performed in Sprawley rats. Samples were analyzed using HPLC. Results: Microwave synthesis yields para-crystalline, porous nanosponges (∼205 nm). Drug entrapment led to enhancement of solubility and a two-fold increase in drug dissolution (P < 0.001) following Higuchi release model. Enhanced oral bioavailability was observed in fasted Sprawley rats where C_max and AUC_0-∞ increases significantly (C_max of NS∼ 586 ± 5.91 ng/mL; plain RLP ∼310 ± 5. 74 ng/mL). Conclusion: The approach offers a comfortable dosing zone for AIDs patients, negating the requirement of consuming the formulation in a fed state due to enhancement in drugs’ oral bioavailability.

In-vitro dissolution study is crucial for quality assurance and stability, serving as a surrogate test for evaluating in-vivo performance of a drug. The dissolution procedure should be designed using an appropriate validated approach, depending on the type of dosage form. Dissolution testing is crucial to regulatory decision-making in a number of aspects. Conventional formulations have validated regulatory-compliant dissolution methods, conversely novel drug formulations like nanoparticles and microparticles lack standard validated procedures for the same. The present article provides information about the various compendial and non-compendial methods available for in-vitro dissolution testing of nano-formulations including the selection of dissolution media, different factors affecting the release, advancements in the dissolution procedures and also included the recently developed marketed nano-formulations.