How Does Fluid Flow Influence Drug Release from Drug Filled Implants?

Drug-filled implants (DFIs) have emerged as an innovative approach to control the delivery of drugs. These devices contain the drug within the structure of the implant itself and avoid the need to include additional drug carrier materials such as a polymers, which are often associated with inflammation and delayed healing/tissue regeneration at the implant site. One common feature of in vitro experiments to generate drug release profiles is stirring or agitation of the release medium. However, the influence of the resulting fluid flow on the rate of drug release from DFIs has yet to be quantified. In this paper we consider two DFIs, which although similar in shape and size, employ different strategies to control the release of drug: a porous pin with pores on the order of μm and a pin drilled with orifices of the order of mm. We develop a multiphysics mathematical model of drug release from these DFIs, subject to fluid flow induced through stirring and show that fluid flow greatly influences the drug release profile for the orifice pin, but that the porous pin drug release profile is relatively insensitive to flow. We demonstrate that drug release from the porous pin may adequately be described through a simplified radial 1D dissolution-diffusion model, while a 3D dissolution-advection-diffusion model is required to describe drug release from the orifice pin. A sensitivity analysis reveals that that the balance of reaction-advection-diffusion in terms of key nondimensional numbers governs the overall drug release. Our findings potentially have important implications in terms of devising the most relevant experimental protocol for quantifying drug release from DFIs.

Evaluation of in vitro Dissolution Profile and Physicochemical Characterization of Polymer Based Formulations of Sparingly Soluble Rosuvastatin

Rosuvastatin (RVT) is a BCS class II antilipidemic crystalline drug, which exhibits low bioavailability due to its very poor aqueous solubility; therefore, it is challenging to develop a proper formulation of RVT. To enhance solubility and bioavailability of this API, an attempt has been made by implementing solid dispersion technique. Solid dispersion (SD) technique is a solubility enhancing technique where one or more active entities are dispersed in an inert medium (matrix or carrier) at solid state. In this study, different ratios of Kollicoat® IR (KIR) and Kollidon® 90F (KF90) polymers were used with API to prepare various formulations by physical mixing (PM) and SD approaches; here solvent evaporation technique was used whereas methanol was used as solvent which was completely evaporated from the homogenously dispersed system by placing in a water-bath at 60-65°C and then in oven for 30 minutes at 50 °C. Among the formulations, RVT-KF90 SD formulations showed the most promising result in in-vitro study in terms of drug release profile (78.04 – 99.21%) in comparison to pure RVT (63.1%) and physical mixing of RVT with those polymers. USP dissolution apparatus type II was used at 37°C ± 0.5°C with 50 rpm to conduct the in-vitro experiment. The experiment also unraveled that the dissolution of RVT improved with increasing the amounts of polymers. Subsequently, stability of the developed formulations was conducted by Fourier transforms infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) as well as scanning electron microscopy (SEM). The results obtained from FTIR ensured no involvement of any significant drug-excipient interaction. Moreover, the DSC study signified thermal stability at high temperature. Besides, the SEM micrograph illustrated homogenous distribution of RVT in the polymer and transformation of crystal-like RVT into amorphous formulations. Dhaka Univ. J. Pharm. Sci. 20(2): 199-211, 2021 (December)

Retrovirus Drugs-Loaded PEGylated PAMAM for Prolonging Drug Release and Enhancing Efficiency in HIV Treatment

Polyamidoamine dendrimer (PAMAM) with its unique characteristics emerges as a potential drug delivery system which can prolong releasing time, reduce the side effects but still retaining treatment efficiency. In this study, methoxy polyethylene glycol modified PAMAM generation 3.0 (G3.0@mPEG) is prepared and characterized via 1H-NMR, FT-IR, and TEM. Subsequently, two antiretroviral agents (ARV) including lamivudine (3TC) and zidovudine (AZT) are individually encapsulated into G3.0@mPEG. The drug-loading efficiency, drug release profile, cytotoxicity and anti-HIV activity are then evaluated. The results illustrate that G3.0@mPEG particles are spherical with a size of 34.5 ± 0.2 nm and a drug loading content of about 9%. Both G3.0@mPEG and [email protected]@mPEG show no cytotoxicity on BJ cells, and G3.0@mPEG loading 3TC and AZT performs sustained drug release behavior which is best fitted with the Korsmeyer–Peppas model. Finally, the anti-HIV activity of ARV via Enzymatic Assay of Pepsin is retained after being loaded into the G3.0@mPEG, in which about 36% of pepsin activity was inhibited by AZT at the concentration of 0.226 mM. Overall, PAMAM G3.0@mPEG is a promising nanocarrier system for loading ARV in HIV treatment and prevention.

Development, Optimization, and In Vitro Evaluation of Novel Oral Long-Acting Resveratrol Nanocomposite In-Situ Gelling Film in the Treatment of Colorectal Cancer

this study aimed to develop and evaluate sustained-release (SR) long-acting oral nanocomposites in-situ gelling films of resveratrol (Rv) to treat colorectal cancer. In these formulations, Rv-Soy protein (Rv-Sp) wet granules were prepared by the kneading method and then encapsulated in the sodium alginate (NA) dry films. The prepared nanocomposite in-situ gels films were characterized using dynamic light scattering, Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The optimized formulations were further evaluated based on drug encapsulation efficiency, pH-drug release profile, swelling study, and storage time effects. The optimized formulation was tested for its anticancer activity against colorectal cancer cells using the cytotoxicity assessment, apoptosis testing, cell cycle analysis, gene expression analysis, and protein estimation by the reverse-transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay methods, respectively. The optimum film showed encapsulation efficiency of 97.87% ± 0.51 and drug release of 14.45% ± 0.043 after 8 h. All physiochemical characterizations confirmed, reasoned, and supported the drug release experiment’s findings and the encapsulation assay. The Rv nanocomposite formulation showed concentration-dependent cytotoxicity enhanced apoptotic activity as compared to free Rv (p < 0.05). In addition, Rv nanocomposite formulation caused a significant increase in Bcl-2-associated protein X (Bax) and a decrease in expression of B-cell lymphoma 2, interleukin 1 beta, IL-6, and tumor necrosis factor-alpha (Bcl2, IL-1β, IL-6, and TNF-α respectively) compared to that of free Rv in HCT-116 cells. These results suggest that long-acting Rv nanocomposite gels could be a promising agent for colorectal cancer treatment.

Fabrication of cefixime nanoparticles loaded films and their ex vivo antimicrobial effect on periodontitis patient’s saliva

Aim: This study was designed to prepare and evaluate cefixime-loaded nanoparticles containing low molecular weight chitosan films for the enhanced topical treatment of periodontitis. Methods: To fabricate the enhanced antimicrobial films, a nanoprecipitation method for cefixime nanoparticles followed by a solvent evaporation method for these nanoparticles loaded films were adopted in this study. Nine batches of nanoparticles (NPs) with different concentrations of ethyl cellulose and polyvinyl alcohol were prepared and evaluated. Furthermore, nine batches of optimized NPs loaded films with different concentrations of low molecular weight chitosan and glycerol were fabricated and evaluated. Optimized NPs loaded films were assessed for their antimicrobial activity against the periodontitis patient’s saliva samples. Results: The FT-IR spectroscopy and XRD study revealed that there was no interaction between the drug and all other excipients and the drug remained amorphous form in chitosan film. The SEM study revealed that the prepared NPs were spherical in shape and uniformly distributed in chitosan film. In vitro drug release study revealed the NPs have a sustained release profile up to 8 days and NPs loaded films have up to 11 days. The conventional marketed mouth wash shows a low inhibition zone of 5.70 ± 0.043 mm, whereas NPs loaded film shows a higher inhibition zone of 6.72 ± 0.063 mm against periodontal microorganisms present in the patient’s saliva. The stability study revealed that the optimized NPs loaded film shows no dramatic change in drug release profile and folding endurance after six months. Conclusion: This present study highlights the possible usage of cefixime NPs loaded films in enhanced periodontal treatment.

Lomustine Incorporated Lipid Nanostructures Demonstrated Preferential Anticancer Properties in C6 Glioma Cell Lines with Enhanced Pharmacokinetic Profile in Mice

Effective treatment of glioma still stands as a challenge in medical science. The work aims for the fabrication and evaluation of lipid based nanostructures for improved delivery of lomustine to brain tumor cells. Experimental formulations (LNLs) were developed by modified lipid layer hydration technique and evaluated for different in vitro characteristics like particle size analysis, surface charge, surface morphology, internal structure, in vitro drug loading, drug release profile etc. Anticancer potential of selected LNLs was tested in vitro on C6 glioma cell line. Electron microscopic study depicted a size of less than 50 nm for the selected LNLs along wirh 8.8% drug loading with a sustained drug release tendency over 48 h study period. Confocal microscopy revealed resonable internalization of the selected LNL in C6 cells. LNLs were found more cytotoxic than free drug and blank nanocarriers as depicted from MTT assay. The selected LNL showed improved pharmacokinetic profile both in blood and brain in the experimental mice models along with negligible hemolysis in mice blood cells. Further studies are warranted for the future translation of LNLs at clinics.

New Formulations Loading Caspofungin for Topical Therapy of Vulvovaginal Candidiasis

Vulvovaginal candidiasis (VVC) poses a significant problem worldwide affecting women from all strata of society. It is manifested as changes in vaginal discharge, irritation, itching and stinging sensation. Although most patients respond to topical treatment, there is still a need for increase the therapeutic arsenal due to resistances to anti-infective agents. The present study was designed to develop and characterize three hydrogels of chitosan (CTS), Poloxamer 407 (P407) and a combination of both containing 2% caspofungin (CSP) for the vaginal treatment of VVC. CTS was used by its mucoadhesive properties and P407 was used to exploit potential advantages related to increasing drug concentration in order to provide a local effect. The formulations were physically, mechanically and morphologically characterized. Drug release profile and ex vivo vaginal permeation studies were performed. Antifungal efficacy against different strains of Candida spp. was also evaluated. In addition, tolerance of formulations was studied by histological analysis. Results confirmed that CSP hydrogels could be proposed as promising candidates for the treatment of VVC.

Hepatoprotective Effects of Bioflavonoid Luteolin Using Self-Nanoemulsifying Drug Delivery System

Luteolin (LUT) is a natural pharmaceutical compound that is weakly water soluble and has low bioavailability when taken orally. As a result, the goal of this research was to create self-nanoemulsifying drug delivery systems (SNEDDS) for LUT in an attempt to improve its in vitro dissolution and hepatoprotective effects, resulting in increased oral bioavailability. Using the aqueous phase titration approach and the creation of pseudo-ternary phase diagrams with Capryol-PGMC (oil phase), Tween-80 (surfactant), and Transcutol-HP (co-emulsifier), various SNEDDS of LUT were generated. SNEDDS were assessed for droplet size, polydispersity index (PDI), zeta potential (ZP), refractive index (RI), and percent of transmittance (percent T) after undergoing several thermodynamic stability and self-nanoemulsification experiments. When compared to LUT suspension, the developed SNEDDS revealed considerable LUT release from all SNEDDS. Droplet size was 40 nm, PDI was <0.3, ZP was −30.58 mV, RI was 1.40, percent T was >98 percent, and drug release profile was >96 percent in optimized SNEDDS of LUT. For in vivo hepatoprotective testing in rats, optimized SNEDDS was chosen. When compared to LUT suspension, hepatoprotective tests showed that optimized LUT SNEDDS had a substantial hepatoprotective impact. The findings of this investigation suggested that SNEDDS could improve bioflavonoid LUT dissolution rate and therapeutic efficacy.

Formulation and Evaluation of Solid Self-Nanoemulsifying Drug Delivery System for Enhancing the Solubility and Dissolution Rate of Budesonide

Objective: To enhance solubility and dissolution rate of budesonide through development of solid self-nanoemulsifying drug delivery system (S-SNEDDS). Methods: Liquid self-nanoemulsifying drug delivery systems (L-SNEDDS) were prepared and ternary phase diagram was constructed using Origin pro 8. Liquid self-nanoemulsifying formulation LF2 having 20% oil and 80% of surfactant/co-surfactant was optimized from the three formulations (LF1-LF3) to convert in to solid, through various characterization techniques like self-emulsification, in vitro drug release profile and drug content estimation. The prepared L-SNEDDS converted into S-SNEDDS, SF1-SF6 by adsorption technique using Aerosil 200, Neusilin US2, and Neusilin UFL2 to improve flowability, compressibility and stability. Results: Formulation LF2 exhibited globule size of 82.4 nm, PDI 0.349 and Zeta potential -28.6 mV with drug indicating the stability and homogeneity of particles. The optimized formulation SF4 containing Neusilin UFL2 was characterized by DSC, FTIR, X-Ray diffraction studies and found no incompatibility and no major shifts were noticed. Formulation SF4 released 100 % drug in 20 min against pure drug release of 47 % in 60 min. Regardless of the form (i.e. liquid or solid) similar performance of emulsification efficiency is observed. Conclusion: The results demonstrated that the technique of novel solid self-nanoemulsifying drug delivery system can be employed to enhance the solubility and dissolution rate of poorly water-soluble drug budesonide.