Musarrat H. Warsi

A review on the strategies for oral delivery of proteins and peptides and their clinical perspectives

In the modern world, a number of therapeutic proteins such as vaccines, antigens, and hormones are being developed utilizing different sophisticated biotechnological techniques like recombinant DNA technology and protein purification. However, the major glitches in the optimal utilization of therapeutic proteins and peptides by the oral route are their extensive hepatic first-pass metabolism, degradation in the gastrointestinal tract (presence of enzymes and pH-dependent factors), large molecular size and poor permeation. These problems can be overcome by adopting techniques such as chemical transformation of protein structures, enzyme inhibitors, mucoadhesive polymers and permeation enhancers. Being invasive, parenteral route is inconvenient for the administration of protein and peptides, several research endeavors have been undertaken to formulate a better delivery system for proteins and peptides with major emphasis on non-invasive routes such as oral, transdermal, vaginal, rectal, pulmonary and intrauterine. This review article emphasizes on the recent advancements made in the delivery of protein and peptides by a non-invasive (peroral) route into the body.

Enhanced bioavailability of nano-sized chitosan–atorvastatin conjugate after oral administration to rats

A novel approach to improve the bioavailability and stability of atorvastatin (AT) was developed by constructing a nano-sized polymer-atorvastatin conjugate. Firstly, a novel chitosan-atorvastatin (CH-AT) conjugate was efficiently synthesized through amide coupling reaction. The formation of conjugate was confirmed by (1)H NMR and FT-IR spectrometry. Nano-sized conjugate with a mean size of 215.3±14.2 nm was prepared by the process of high pressure homogenization (HPH). Scanning electron microscopy (SEM) revealed that CH-AT nano-conjugate possess smooth surface whereas X-ray diffraction (XRD) spectra demonstrated amorphous nature of nano-conjugate. Further, CH-AT nano-conjugate showed solubility enhancement of nearly 4-fold and 100-fold compared to CH-AT conjugate and pure AT, respectively. In vitro drug release studies in simulated gastric fluid and simulated intestinal fluid suggested sustained release of AT from the conjugate. Additionally, the nano-conjugate significantly reduced the acidic degradation of AT. The plasma-concentration time profile of AT after oral administration of CH-AT nano-conjugate (2574±95.4 ng/mL) to rat exhibited nearly 5-fold increase in bioavailability compared with AT suspension (583±55.5 ng/mL). Finally, variable bioavailability, as observed for AT suspension was also reduced when AT was administered in form of CH-AT nano-conjugate. Taken together these data demonstrate that chitosan conjugate nano-prodrugs may be used as sustained polymeric prodrugs for enhancing bioavailability.

Development and evaluation of nanosized niosomal dispersion for oral delivery of Ganciclovir

Encapsulation of Ganciclovir in lipophilic vesicular structure may be expected to enhance the oral absorption and prolong the existence of the drug in the systemic circulation. So the purpose of the present study was to improve the oral bioavailability of Ganciclovir by preparing nanosized niosomal dispersion. Niosomes were prepared from Span40, Span60, and Cholesterol in the molar ratio of 1:1, 2:1, 3:1, and 3:2 using reverse evaporation method. The developed niosomal dispersions were characterized for entrapment efficiency, size, shape, in vitro drug release, release kinetic study, and in vivo performance. Optimized formulation (NG8; Span60:Cholesterol 3:2 molar ratio) has shown a significantly high encapsulation of Ganciclovir (89 ± 2.13%) with vesicle size of 144 ± 3.47 nm (polydispersity index [PDI] = 0.08). The in vitro release study signifies sustained release profile of niosomal dispersions. Release profile of prepared formulations have shown that more than 85.2 ± 0.015% drug was released in 24 h with zero-order release kinetics. The results obtained also revealed that the types of surfactant and Cholesterol content ratio altered the entrapment efficiency, size, and drug release rate from niosomes. In vivo study on rats reveals five-time increment in bioavailability of Ganciclovir after oral administration of optimized formulation (NG8) as compared with tablet. The effective drug concentration (>0.69 µg/mL in plasma) was also maintained for at least 8 h on administration of the niosomal formulation. In conclusion, niosomes can be proposed as a potential oral delivery system for the effective delivery of Ganciclovir.

Enhanced antimalarial activity of lumefantrine nanopowder prepared by wet-milling DYNO MILL technique

Lumefantrine (LMF) is an antimalarial drug that exhibits poor oral bioavailability, owing to its poor aqueous solubility. To improve its antimalarial activity, nanopowder formulation using DYNO MILL was prepared. Combination of HPMC E3 (4%, w/v) and Tween 80 (2.5%, w/v) as dispersing agents, favored the production of smaller LMF particles with mean size of 0.251 μm. LMF nanopowder showed enhanced dissolution rate attributed to nanonization of LMF. The IC(50) value of nano-sized LMF was found to be 0.1 ng/mL, which was 175-times lower than the IC(50) value of unmilled LMF powder (17.5 ng/mL) and 42-times lower than the IC(50) value of chloroquine (4.2 ng/mL). The in vivo antimalarial activity demonstrated an enhanced antimalarial potential of LMF nanopowder against P. Yoelii nigeriensis compared to unmilled drug. Wet-milling using DYNO MILL offers a highly effective approach to produce stable drug nanopowders. Furthermore, LMF nanopowder makes the Coartem therapy more effective.

Dual approach utilizing self microemulsifying technique and novel P-gp inhibitor for effective delivery of taxanes.

In the present work, concomitant use of self-microemulsifying drug delivery systems (SMEDDS) and a novel third-generation P-gp inhibitor, GF120918 (elacridar), for the effective transport of taxanes (paclitaxel and docetaxel) across an in vitro model of the intestinal epithelium and uptake into tumor cells were investigated. On the basis of solubility studies and ternary phase diagrams, different SMEDDS formulations of taxanes were prepared and characterized. In caco-2 cell permeation study, paclitaxel-loaded SMEDDS along with GF120918 showed a four-fold increase in apparent permeability, while docetaxel-loaded SMEDDS in combination with GF120918 showed a nine-fold increase in permeability, as compared to plain drug solution. Cell uptake studies on A549 cells were performed with microemulsions formed from both SMEDDS formulations loaded with rhodamine 123 dye and showed good uptake than plain dye solution. Confocal laser scanning microscopic images further confirmed the higher uptake of both SMEDDS formulations in the presence of GF120918.

Dorzolamide-loaded PLGA/vitamin E TPGS nanoparticles for glaucoma therapy: Pharmacoscintigraphy study and evaluation of extended ocular hypotensive effect in rabbits.

Poor drug penetration and rapid clearance after topical instillation of a drug formulation into the eyes are the major causes for the lower ocular bioavailability from conventional eye drops. Along with this, poor encapsulation efficiency of hydrophilic drug in polymeric nanoparticles remains a major formulation challenge. Taking this perspective into consideration, dorzolamide (DZ)-loaded PLGA nanoparticles were developed employing two different emulsifiers (PVA and vitamin E TPGS) and the effects of various formulation and process variables on particle size and encapsulation efficiency were assessed. Nanoparticles emulsified with vitamin E TPGS (DZ-T-NPs) were found to possess enhanced drug encapsulation (59.8±6.1%) as compared to those developed with PVA as emulsifier (DZ-P-NPs). Transcorneal permeation study revealed a significant enhancement in permeation (1.8-2.5 fold) as compared to solution. In addition, ex vivo biodistribution study showed a higher concentration of drug in the aqueous humour (1.5-2.3 fold). Histological and IR-camera studies proved the non-irritant potential of the formulations. Pharmacoscintigraphic studies revealed the reduced corneal clearance, as well as naso-lachrymal drainage in comparison to drug solution. Furthermore, efficacy study revealed that DZ-P-NPs and DZ-T-NPs significantly reduced the intraocular pressure by 22.81% and 29.12%, respectively, after a single topical instillation into the eye.

Nano-vectors for the Ocular Delivery of Nucleic Acid- based Therapeutics

Nucleic acid-based therapeutics have gained a lot of interest for the treatment of diverse ophthalmic pathologies. The first to enter in clinic has been an oligonucleotide, Vitravene® for the treatment of cytomegalovirus infection. More recently, research on aptamers for the treatment of age related macular degeneration has led to the development of Macugen®. Despite intense potential, effective ocular delivery of nucleic acids is a major challenge since therapeutic targets for nucleic acid-based drugs are mainly located in the posterior eye segment, requiring repeated invasive administration. Of late, nanotechnology-based nano-vectors have been developed in order to overcome the drawbacks of viral and other non-viral vectors. The diversity of nano-vectors allows for ease of use, flexibility in application, low-cost of production, higher transfection efficiency and enhanced genomic safety. Using nano-vector strategies, nucleic acids can be delivered either encapsulated or complexed with cationic lipids, polymers or peptides forming sustained release systems, which can be tailored according to the ocular tissue being targeted. The present review focuses on developments and advances in various nano-vectors for the ocular delivery of nucleic acid-based therapeutics, the barriers that such delivery systems face and methods to overcome them.

Quantification of curcumin, demethoxycurcumin, and bisdemethoxycurcumin in rodent brain by UHPLC/ESI-Q-TOF-MS/MS after intra-nasal administration of curcuminoids loaded PNIPAM nanoparticles

An ultra high performance liquid chromatography-electrospray ionization-synapt mass spectrometric method (UHPLC/ESI-QTOF-MS/MS) for the analysis of curcumin (Cur), demethoxycurcumin (DMC), bisdemethoxycurcumin (BDMC) in Wistar rat brain homogenate was developed and validated. The chromatographic separation was achieved on a Waters ACQUITY UPLC™ BEH C18 (2.1mm × 100 mm; 1.7μm) column using isocratic mobile phase, consisting of acetonitrile: 10mM ammonium formate: formic acid (90:10:0.05v/v/v), at a flow rate of 0.2 ml min(-1) . The transitions occurred at m/z 367.0694/217.0598, 337.0717/173.0910, 307.0760/187.0844 for Cur, DMC, BDMC and m/z 307.0344/229.0677 for the IS (Nimesulide) respectively. The recovery of the analytes from Wistar rat brain homogenate was optimized using liquid-liquid extraction technique (LLE) in (ethyl acetate: chloform) mixture. The total run time was 3.0 min and the elution of Cur, DMC, BDMC occurred at 1.6, 1.75, 1.70 min, and for the IS 1.87 min, respectively. The linear dynamic range was established over the concentration range of 1.00 ng mL(-1) to 1000.0 ng mL(-1) (r(2) ; 0.9909 ± 0.0011, 0.9911 ± 0.003, and 0.9919 ± 0.0013) for Cur, DMC, and BDMC, respectively. The intra and inter-assay accuracy in terms of % CV for Cur, DMC, and BDMC was in the range 0.47-2.20, 0.47-1.65, and0.44-2.70, respectively. The lower limit of detection (LOD) and quantitation (LOQ) for Cur, DMC, and BDMC were 0.46, 0.05, 0.16 ng mL(-1) and 0.153, 0.015, 0.052 ng mL(-1) , respectively. Analytes were stable and the method proved to be accurate (recovery, >85%), specific and was applied to evaluate the Cur, DMC, BDMC loaded PNIPAM NPs as vehicles for nose to brain drug delivery.

Experimental investigation and oral bioavailability enhancement of nano-sized curcumin by using supercritical anti-solvent process.

The biomedical applications of curcumin (CUR) are limited due to its poor oral bioavailability. In this work, CUR nanoparticles were successfully prepared by combining the supercritical anti-solvent (SAS) process with Tween 80 as a solubilizing agent and permeation enhancer. Different processing parameters that can govern the mean particle size and size distribution of nanoparticles were well investigated by manipulating the types of solvents, mixing vessel pressure, mixing vessel temperature, CO2 flow rate, solution flow rate and solution concentration. Solid state characterization was done by Fourier Transform infrared spectroscopy, differential scanning calorimetry, dynamic light scattering, scanning electron microscopy, and powder X-ray diffraction study. Solubility and dissolution profile of SAS-processed CUR were found to be significantly increased in comparison with native CUR. Further, a validated ultra-performance liquid chromatographic method with quadrupole-time of flight-mass spectrometry was developed to investigate the pharmacokinetic parameters after a single oral dose (100mg/kg) administration of CUR (before/after SAS-processed) in male Wistar rats. From the plasma concentration vs. time profile graph, oral bioavailability of SAS-processed CUR was found to be increased approximately 11.6-fold (p<0.001) as compared to native CUR.

Therapeutic stratagems for vascular degenerative disorders of the posterior eye

In this review we discuss insights into therapeutic stratagems that can selectively target the choroid, retinal cells and vitreoretinal space for the treatment of vision-threatening vascular degenerative disorders of the posterior eye. Despite the relative success of these novel drugs, new problems related to its delivery remain. Systems carrying drugs to the target site, such as nanoparticles, liposomes, vectosomes, spanlastics, micelles, dendrimers and implants are also discussed. Further, we also consider drug penetration enhancement approaches along with cutting-edge strategies for regaining vision during vision-threatening vascular degenerative disorders of the eye. Finally, challenges, such as ocular or even systemic complications associated with use of prolonged therapies and future prospects, such as combination of approaches with multidisciplinary integration to optimize delivery to the posterior eye are also addressed.