Optimization and in vivo evaluation of duloxetine hydrochloride buccoadhesive lyophilized tablets

Duloxetine hydrochloride (DH) is a serotonin-norepinephrine reuptake inhibitor (SSNRI) indicated for the treatment of depression. Duloxetine suffers from reduced oral bioavailability (≈50%) due to hepatic metabolism. DH buccoadhesive lyophilized tablets were prepared adopting the solvent casting/freeze drying method using HPMC, chitosan and carbopol alone or in combination with PVA. The prepared tablets were evaluated for uniformity of weight, drug content, pH, swelling behavior, mucoadhesion strength and drug release and the data was analyzed using Design-Expert® Software. DSC, FTIR studies and scanning electron microscopy (SEM) were performed for the selected tablets. Accelerated stability and bioavailability studies in healthy human volunteers were also performed. Results showed that (T7) tablets showed the optimum physicochemical characters. DSC and FTIR studies showed the drug compatibility with the tablet components. SEM micrographs revealed that the selected tablets were porous and homogenous. Accelerated stability studies revealed that DH remained stable throughout the experiment time. Bioavailability results showed that Cmax and AUC0-72 for T7 was higher than the market product (Cymbalta® 30 mg capsules), while, Tmax was shorter. The percentage relative bioavailability of DH was 308.17%. These results reveal the possibility of T7 tablets to deliver the drug via the buccal route with improved drug bioavailability.