Recent Patents on Drug Delivery & Formulation - Volume 12, Issue 3, 2018

Aims and Background: The number of pathogenic microorganisms has been increasing over the years, and so as resistance of these microorganisms are developing against various antibiotics. Antimicrobial photodynamic therapy (aPDT), also called photodynamic inactivation, is emerging as a promising alternative to treatments based on conventional antibiotics. Recent patents on structured silver mesoporous silica nanoparticles having antimicrobial activity (WO2010/071831 A2), photosensitiser modified core-shell structure nanocomposites (CN 103536935(A)), and Chitosan-coated magnetic mesoporous silica nanoparticles (MSN) (CN 104785214(A)) helped in selecting method of synthesis of MSN and photosensitizers. Materials and Methods: MSN were synthesised by Sol-Gel method and amino functionalised (APTES). Methylene blue (MB) and ortho-toluidine blue (O-TB) were used as photosensitisers. Different batches were synthesised. The final product was characterised by using FTIR, BET, SEM, time resolved fluorescence. The photosensitiser loaded MSN were illuminated by LED based lamp emitting red light at 620± 20nm for different time lengths viz 15 min and 30 mins. Fluorescence studies and antimicrobial assays were carried out as per 72 well plate method I.P, 2014 using, gram negative E. coli (ATCC no. 8739), S. aureus (ATCC no. 7447) and gram positive P. aeruginosa (ATCC no. 9027) pathogenic microorganisms. Results: MB and O-TB were successfully adsorbed on APTES functionalised MSN. Different exposure time length of the photosensitisers to red light showed different zone of inhibition. MB and O-TB loaded MSN showed significant increase in zone of inhibition after irradiation as compared to MB and O-TB loaded on MSN without exposure to light. Conclusion: MB and O-TB adsorbed on APTES functionalized mesoporous silica nanoparticles were capable of efficiently inactivating E. coli, P. aeruginosa, S. aureus bacteria upon exposure to red light (620± 20nm wavelength) at a much lower concentration. Mesoporous silica nanoparticles played an important role in aPDT due to their high surface area and porous structure. Also, APTES functionalization resulted in the pore expansion of MSN, thereby increasing the loading capacity of the photosensitizer on MSN. From the results obtained it can be concluded that O-TB loaded MSN showed higher activity against gram negative and positive microorganisms microorganism as compared to that of MB.

Aims and Background: The objective of the study was to improve the bioavailability of poorly soluble repaglinide (RPG) by preparing nanosuspension with poloxamer 188 using high pressure homogenization (HPH). The recent patents on nanocrystals (US20150337006A1) facilitated selection of drug and polymer. Methods: Suspensions containing dissimilar sized particles were prepared by ultrasonication and HPH. The prepared aqueous suspensions were lyophilized and then characterized. Further, the dried aqueous suspensions were evaluated for drug content, solubility, in vitro dissolution, oral bioavailability study and stability study. Results: RPG nanoparticles size, polydispersity index (PDI) and zeta potential were found to be 280.8 ± 15 nm, 0.279 ± 0.04 and - 25.81 ± 1.6mV, respectively. DSC and XRD results showed that RPG particles in aqueous suspensions were present in a crystalline state; however, RPG nanoparticles exhibited decreased lattice energy due to smaller particle size. Nanoparticles prepared by HPH exhibited significant improvements in solubility and dissolution rate. Oral bioavailability was found to be enhanced by 1.93 fold in comparison with that of plain RPG. The nanosuspension was found to be stable when stored at 5°C ± 3°C. Conclusion: The outcomes of the study revealed significant enhancement in dissolution rate and oral bioavailability of RPG due to size reduction to nano range by HPH.

Background: Herbal drugs are gaining exponential scientific recognition due to their distinct advantages. In the last 2-3 decades, a gradual increase in worldwide patents on herbal nanoformulations has been noted to address the solubility and bioavailability issues of phytoceuticals. Struvite or ammonium magnesium phosphate hexahydrate (NH4MgPO4.6H2O) is among the important urinary infection stones causing painful urological ailment. These smaller stones may bind together to form bigger staghorn calculus. Urinary tract infections caused by some gram positive and gram negative bacteria further enhance the chance of formation of such stones. Oxalis corniculata Linn. is an edible plant, traditionally used in the treatment of bacterial infections and kidney stones. However, there is no scientific evidence to relate the use of O. corniculata against struvite kidney stones. Hence, the antibacterial and struvite stones inhibition activity of the aqueous extract of Oxalis corniculata Linn. leaves and its biofabricated silver nanoparticles (AgNPs) was studied. Methods: The aqueous extract of O. corniculata was prepared by Soxhlet extraction. AgNPs were synthesized using green technique and were characterized using UV and IR spectroscopy, XRD, TEM, DLS and zeta potential studies. Antibacterial activity of the aqueous extract and the silver nanoparticles was tested against E. coli (gram negative) and S. aureus (gram positive) species. Struvite stones were grown in a gel medium by in vitro single diffusion gel growth technique and its inhibition study was carried out using the extract and its biofabricated nanoparticles. Results: The aqueous extract and its biofabricated AgNPs exhibited potent antibacterial activity against both gram positive and gram negative strains of bacteria. The aqueous extract also effectively repressed the growth of struvite stones and led to the dissolution of stones, but the inhibitory effect was further enhanced by its biofabricated AgNPs. Conclusion: The present work confirms the inhibitory activity of the aqueous extract of edible O. corniculata and its biofabricated silver nanoparticles against urinary tract infection (UTI) causing bacteria and urolithiasis. Therefore, the consumption of O. corniculata in our daily diet may reduce the risk of UTI and urolithiasis.

Objective: The aim of the present investigation entails the development of solid SMEDDS for improving the oral bioavailability of canagliflozin using porous carriers. The previous patent (WO2017046730A1) was based on enhanced solubility of canagliflozin through co-crystal formation. Methods: Preconcentrates were prepared by employing Lauroglycol (80 mg), Tween 80 (300 mg) and Transcutol P (120 mg) and successfully adsorbed onto various hydrophilic and hydrophobic carriers. The prepared solid SMEDDS were characterized for various parameters to determine the optimized formulation. In vitro, ex vivo and in vivo studies were carried out to determine drug release kinetics, permeation and absorption rate, respectively. Stability of the formulation was investigated at 45°C/75% RH. Results: The solid preconcentrates prepared with hydrophobic carriers exhibited desired attributes in a uniform range. Neusilin adsorbed solid SMEDDS (S(N)SMEDDS) portrayed enhanced amorphization in XRD and DSC studies and found to be physically compatible in FTIR studies. SEM revealed colloidal particles having spherical morphology with negligible aggregation. Ex vivo permeation rate of the drug across excised intestinal segments (duodenum, jejunum, ileum and colon) was observed to be 3.72, 5.85, 4.51 and 3.0-fold, respectively, as compared to pure drug. TEM of reconstituted SMEDDS indicated nano-sized globules with negligible coalescence. Enhanced in vitro dissolution rate of optimized solid SMEDDS manifested in bioavailability enhancement of 167.54% and 188.98%, as compared to pure drug and marketed product. These studies further substantiate the lymphatic uptake of SMEDDS through chylomicron flow blocking approach. Establishment of Level A IVIVC showed a uniform correlation between the in vitro dissolution efficiency and in vivo pharmacokinetic parameters. Conclusion: The present investigation reveals the immense potential of solid SMEDDS in augmenting the oral bioavailability profile of poorly water-soluble drug canagliflozin.

Purpose: The purpose of the study was formulation development, optimization and evaluation of a Self-Emulsifying Drug Delivery System (SEDDS) of Simvastatin (SIM) for improvement in dissolution and bioavailability of SIM. Solubility enhancement of Biopharmaceutical Classification System (BCS) Class-II drugs is a burning topic and attracting various publications and patents regarding different strategies employed for improvement of dissolution viz., USOO5340591A (Solid dispersion), US005472954A, US005646131A (complexation), USOO5858410A (Nanosuspensions), USOO5874029A (micronization) US2008.00095O2A1 (Solid composites), US2008O146640A1 (Prodrug) US 2009001 1009 A1 (nanocapsules), etc. Methods: SEDDS was prepared on the basis of solubility studies employing Capmul MCM EP as lipid and Cremophor ELP as surfactant. Box-Behnken design was implemented for optimization by using lipid concentration, surfactant concentration and mixing time as dependent variables and their impact was observed on particle size, poly dispersity index (PDI) and drug released in 15min. Optimized formulation was evaluated for particle size, PDI, zeta potential, emulsification time, transmittance, invitro drug release and in situ Single-Pass Intestinal Perfusion (SPIP) studies. Results: For optimized formulation, OF1 value of particle size, PDI, zeta potential, emulsification time, transmittance and percent in-vitro release were 162±14.32nm, 0.19±0.01, -22.3 ±1.1mV, 93±3.11 sec, 99.45±4.35 % and 99.43± 5.6 % in 30 min respectively. In-situ SPIP studies were performed on Wistar rats and the value of predicted fraction absorbed for humans was found to be 0.98. Conclusion: SIM SEDDS was successfully developed and evaluated for in-vitro & in-vivo parameters. All the evaluated parameters were in tolerable limits. In vitro release studies from optimized formulation, OF1, exhibited maximum drug release when compared to SIM API and marketed preparation. Moreover, the predicted value of fraction absorbed (Fa) in humans by in-situ SPIP method was also in agreement with in-vitro dissolution studies thus, confirming SEDDS as a suitable drug delivery system for solubility enhancement of SIM.

Background: While protein therapeutics are invaluable in managing numerous diseases, many require frequent injections to maintain therapeutically effective concentrations, due to their short half-life in circulation. PolyXen™, a platform and patented technology employing biodegradable, non-immunogenic and hydrophilic Polysialic Acids (PSA) for drug delivery, is being utilized to overcome such limitations, thereby potentially enabling the clinical utility of a broad range of protein therapeutics. Here, we report the recent progress on two development candidates, polysialylated deoxyribonuclease I (PSA-DNase) and polysialylated erythropoietin (PSA-EPO). Methods and Results: Chemical polysialylation of DNase I (DNase) using PSA with different chain length at various conjugation sites led to improved stability against proteases and thermal stress, and slightly reduced enzymatic activity. Polysialylation of EPO resulted in retention of protein structure and PSA-EPO remained biologically active. PSA-EPO had a significantly prolonged circulating half-life (e.g. t1/2 of PSA-EPO = ~400 h in patients after subcutaneous administration, aimed for once monthly administration, vs. t1/2 of EPO = ~22 h; administered twice or thrice weekly), and retained in vivo efficacy. Conclusion: This approach has been clinically validated in phase I (in healthy volunteers) and II studies of PSA-EPO [for managing anemia in patients with chronic kidney disease (CKD)].