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BackgroundPterostilbene has a proven chemopreventive effect for colon carcinogenesis but suffers low bioavailability limitations and therefore unable to reach the colonic tissue.Objective and methodologyTo overcome the issue of low bioavailability, pterostilbene was formulated into an oral colon targeted beads by ionic gelation method using pectin and zinc acetate. Optimization was carried out by 23 factorial design whereby the effect of pectin concentration (X1), zinc acetate concentration (X2) and pterostilbene:pectin ratio (X3) were studied on entrapment efficiency (Y1) and in vitro drug release till 24 h (Y2). The optimized beads were characterized for shape and size, swelling and surface morphology. The optimized beads were uniformly coated with Eudragit S-100 using fluidized bed coater. Optimized coated beads were characterized for in vitro drug release till 24 h and surface morphology. Pharmacokinetic and organ distribution study were performed in rats to ascertain the release of pterostilbene in colon.ResultsThe optimized formulation comprised of 2% w/v of pectin concentration (X1), 2% w/v of zinc acetate concentration (X2) and 1:4 of pterostilbene:pectin ratio (X3), which showed a satisfactory entrapment efficiency (64.80%) and in vitro release (37.88%) till 24 h. The zinc pectinate beads exhibited sphericity, uniform size distribution, adequate swelling and rough surface. The optimized coated beads achieved 15% weight gain, displayed smooth surface and optimum drug release. Pterostilbene from optimized coated beads appeared in the plasma at 14 h and reached the Cmax at 22 h (Tmax), whereas plain pterostilbene exhibited Tmax of 3 h.Discussion and conclusionThus, larger distribution of pterostilbene was obtained in the colonic tissue compared to stomach and small intestinal tissues. Thus, delayed Tmax and larger distribution of pterostilbene in colonic tissue confirmed the targeting of beads to colon.

Soft contact lenses have been demonstrated as a promising tool for ocular drug delivery. In the present investigation ganciclovir (GAN) loaded microparticles dispersed in hydrogel-based contact lenses were fabricated to achieve prolonged release and improved permeation of GAN across corneal epithelium. MethodsGAN-Hydroxy Propyl Methyl Cellulose (HPMC) microparticles were prepared by solvent evaporation method and evaluated for entrapment e ciency, drug content and drug release. The Polyhydroxyethylmethacrylate (pHEMA) contact lenses were synthesized by free radical polymerization reaction using crosslinkers like ethylene glycoldimethacrylate and photoinitiator such as IRGACURE 1173®, in UVB light, λ 365 nm. The GAN-HPMC microparticles when incorporated into the premonomer mixture and polymerized together give rise to a particle dispersion system in the hydrogel contact lenses.The contact lenses were studied for surface morphology, transmittance, swelling, drug release, Na + ion permeability and hens egg test chorioallantoic membrane assay (HETCAM). ResultsHydrogel contact lens exhibited satisfactory surface morphology, transmittance, swelling, Na + ion permeability (3.72x106 mm 2 /min) and a release of 48 hours suggesting a potential for prolonged ocular drug delivery. Furthermore, HETCAM exhibited no signs of ocular irritation. ConclusionThe developed delivery platform is a promising alternative to conventional dosage forms like eye drops, suspensions and ointments due to its increase in the residence time attributed to its prolonged release pro le. Hence, drug delivery by hydrogel-based contact lens decreases the systemic effects of the drugs which are meant for local action, thus, enhances the therapeutic use by improving the patient compliance.

Retinoblastoma (RB), a childhood retinal cancer is caused due to RB1 gene mutation which affects the child below 5 years of age. Angiogenesis has been proven its role in RB metastasis due to the presence of vascular endothelial growth factor (VEGF) in RB cells. Therefore, exploring angiogenic pathway by inhibiting VEGF in treating RB would pave the way for future treatment. In preclinical studies, anti-VEGF molecule have shown their efficacy in treating RB. However, treatment requires recurrent intra-vitreal injections causing various side effects along with patient nonadherence. As a result, delivery of anti-VEGF agent to retina requires an ocular delivery system that can transport it in a non-invasive manner to achieve patient compliance. Moreover, development of these type of systems are challenging due to the complicated physiological barriers of eye. Adopting a non-invasive or minimally invasive approach for delivery of anti-VEGF agents would not only address the bioavailability issues but also improve patient adherence to therapy overcoming the side effects associated with invasive approach. The present review focuses on the eye cancer, angiogenesis and various novel ocular drug delivery systems that can facilitate inhibition of VEGF in the posterior eye segment by overcoming the eye barriers.

Purpose Soft contact lenses have been demonstrated as a promising tool for ocular drug delivery. In the present investigation ganciclovir (GAN) loaded microparticles dispersed in hydrogel-based contact lenses were fabricated to achieve prolonged release and improved permeation of GAN across corneal epithelium. Methods GAN-Hydroxy Propyl Methyl Cellulose (HPMC) microparticles were prepared by solvent evaporation method and evaluated for entrapment efficiency, drug content and drug release. The Polyhydroxyethylmethacrylate (pHEMA) contact lenses were synthesized by free radical polymerization reaction using crosslinkers like ethylene glycoldimethacrylate and photoinitiator such as IRGACURE 1173®, in UVB light, λ 365 nm. The GAN-HPMC microparticles when incorporated into the premonomer mixture and polymerized together give rise to a particle dispersion system in the hydrogel contact lenses. The contact lenses were studied for surface morphology, transmittance, swelling, drug release, Na + ion permeability and hens egg test chorioallantoic membrane assay (HETCAM). Results Hydrogel contact lens exhibited satisfactory surface morphology, transmittance, swelling, Na + ion permeability (3.72x106 mm2/min) and a release of 48 hours suggesting a potential for prolonged ocular drug delivery. Furthermore, HETCAM exhibited no signs of ocular irritation. Conclusion The developed delivery platform is a promising alternative to conventional dosage forms like eye drops, suspensions and ointments due to its increase in the residence time attributed to its prolonged release profile. Hence, drug delivery by hydrogel-based contact lens decreases the systemic effects of the drugs which are meant for local action, thus, enhances the therapeutic use by improving the patient compliance.