Design of a pilot plant-type pharmaceutical reactor to address the problem of interchangeability of generic semisolid formulations.

OBJECTIVE AND SIGNIFICANCE: This research aims to design and develop a pilot plant-type pharmaceutical reactor with a strong focus on its volumetric capacity and heat transfer capabilities. The primary goal is to replicate design and control strategies at the laboratory or pilot scale to analyze and produce generic semisolid formulations. METHODS: Computational fluid dynamics and heat transfer modeling, utilizing the finite volume method, were employed to determine the reactor's performance and particle trajectory during the mixing and stirring. This allowed for the establishment of optimal operational parameters and variables. Furthermore, prototypes were constructed at 1:2.5 and 1:15 scales to examine the reactor's morphology, ensure volumetric versatility, and conduct mixing, homogenization, and coloration tests using varying volumes. RESULTS AND CONCLUSIONS: The outcomes of this study yielded a versatile reactor suitable for processing pharmaceutical semisolids at both laboratory and pilot-scale volumes. Notably, the reactor demonstrated exceptional volumetric capacity within a single vessel while effectively facilitating heat transfer to its interior.

In vivo efficacy of bevacizumab-loaded albumin nanoparticles in the treatment of colorectal cancer.

Bevacizumab (as other monoclonal antibodies) has now become a mainstay in the treatment of several cancers in spite of some limitations, including poor tumour penetration and the development of resistance mechanisms. Its nanoencapsulation may be an adequate strategy to minimize these problems. The aim of this work was to evaluate the efficacy of bevacizumab-loaded nanoparticles (B-NP-PEG) on a xenograft model of human colorectal cancer. For this purpose, human serum albumin nanoparticles were prepared by coacervation, then coated with poly(ethylene glycol) and freeze-dried. B-NP-PEG displayed a mean size of about 300 nm and a bevacizumab loading of approximately 145 µg/mg. An in vivo study was conducted in the HT-29 xenograft model of colorectal cancer. Both, free and nanoencapsulated bevacizumab, induced a similar reduction in the tumour growth rate of about 50%, when compared to controls. By microPET imaging analysis, B-NP-PEG was found to be a more effective treatment in decreasing the glycolysis and metabolic tumour volume than free bevacizumab, suggesting higher efficacy. These results correlated well with the capability of B-NP-PEG to increase about fourfold the levels of intratumour bevacizumab, compared with the conventional formulation. In parallel, B-NP-PEG displayed six-times lower amounts of bevacizumab in blood than the aqueous formulation of the antibody, suggesting a lower incidence of potential undesirable side effects. In summary, albumin-based nanoparticles may be adequate carriers to promote the delivery of monoclonal antibodies (i.e. bevacizumab) to tumour tissues. Graphical abstract.

In vivo effect of bevacizumab-loaded albumin nanoparticles in the treatment of corneal neovascularization.

Corneal neovascularization (CNV) is associated with different ocular pathologies, including infectious keratitis, trachoma or corneal trauma. Pharmacological treatments based on the topical application of anti-VEGF therapies have been shown to be effective in the treatment and prevention of CNV. The aim of this work was to evaluate the effect of bevacizumab-loaded albumin nanoparticles in a rat model of CNV. Bevacizumab-loaded nanoparticles, either "naked" (B-NP) or coated with PEG 35,000 (B-NP-PEG), were administered once a day in the eyes of animals (10 µL, 4 mg/mL every 24 h) during 7 days. Bevacizumab and dexamethasone were employed as controls and administered at the same dose every 12 h. At the end of the study, the area of the eye affected by neovascularization was about 2-times lower for animals treated with B-NP than with free bevacizumab. In the study, dexamethasone did not demonstrate an inhibitory effect on CNV at the employed dose. All of these results were confirmed by histopathological analysis, which clearly showed that eyes treated with nanoparticles displayed lower levels of fibrosis, inflammation and edema. In summary, the encapsulation of bevacizumab in human serum albumin nanoparticles improved its efficacy in an animal model of CNV.

Human serum albumin nanoparticles for ocular delivery of bevacizumab.

Bevacizumab-loaded nanoparticles (B-NP) were prepared by a desolvation process followed by freeze-drying, without any chemical, physical or enzymatic cross-linkage. Compared with typical HSA nanoparticles cross-linked with glutaraldehyde (B-NP-GLU), B-NP displayed a significantly higher mean size (310 nm vs. 180 nm) and a lower negative zeta potential (-15 mV vs. -36 mV). On the contrary, B-NP displayed a high payload of approximately 13% when measured by a specific ELISA, whereas B-NP-GLU presented a very low bevacizumab loading (0.1 µg/mg). These results could be related to the inactivation of bevacizumab after reacting with glutaraldehyde. From B-NP, bevacizumab was released following an initial burst effect, proceeded by a continuous release of bevacizumab at a rate of 6 µg/h. Cytotoxicity studies in ARPE cells were carried out at a single dose up to 72 h and with repeated doses over a 5-day period. Neither bevacizumab nor B-NP altered cell viability even when repeated doses were used. Finally, B-NP were labeled with 99mTc and administered as eye drops in rats. 99mTc-B-NP remained in the eye for at least 4 h while 99mTc-HSA was rapidly drained from the administration point. In summary, HSA nanoparticles may be an appropriate candidate for ocular delivery of bevacizumab.

RP-HPLC method development for the simultaneous determination of timolol maleate and human serum albumin in albumin nanoparticles.

An isocratic high-performance liquid chromatographic method was developed and validated for the simultaneous determination of human serum albumin (HSA) and timolol in albumin nanoparticles. This method involved a reversed-phase-C18 column thermostated at 25 °C, UV detection at 276 nm, flow rate of 1.0 ml/min and a mobile phase compounded by 0.05% (v/v) trifluoroacetic acid in water/0.05% (v/v) trifluoroacetic acid in an acetonitrile (40:60, v/v) solution. The elution times for albumin and timolol were 1.84 ± 0.05 min and 2.67 ± 0.04 min, respectively. Calibration curves were linear from 0.2 to 100 mg/ml for HSA and 0.01 to 1 mg/ml for timolol. Limits of quantification were 0.2 mg/ml for HSA and 0.01 mg/ml for timolol. The values of accuracy and precision of intra- and inter-day variation studies were within acceptable limits, according to the US Food and Drug Administration Guidance for Industry. The described method has proved to be useful to give accurate measurements of human serum albumin and timolol from albumin nanoparticles to determine the percentage of encapsulation and the process yield.

New mucoadhesive polymeric film for ophthalmic administration of acetazolamide.

This article reports the results concerning the design and manufacture of a novel polymeric film for ocular administration of acetazolamide (AZM), and a patent document presented to INPI- National Institute of Industrial/Intelectual Property. The system was designed using mucoadhesive polymers, such as carbomer (CB974P) and sodium carboxymethylcellulose (NaCMC), combined with the poloxamer (POL407) which behaves as a swelling modulator, surfactant and slightly plasticizer. The maximum amount of AZM to be incorporated without loss of homogeneity or precipitation of the drug, was 0.04 mg AZM/mg of the film. The addition of a polymeric coating based on Eudragit RSPO (cationic permeable polymethacrylate polymer) allowed optimizing drug release. The coating in a proportion of 10% (determined as percentage of total weight of the film) seemed to be the most adequate, since 80% of controlled drug release was achieved along 240 minutes. This coating membrane did not affect the mucoadhesive properties of the swellable polymers. Thus, the system obtained, showed good efficiency and the intra ocular pressure (IOP) decreased according to the results derived from in vivo studies performed on normotensive rabbits. Finally, irritation scored studies demonstrated that these systems were not irritant for rabbit´s ocular mucosa.

HPLC method for the determination of nystatin in saliva for application in clinical studies.

An isocratic high-performance liquid chromatographic method was developed, optimized and validated for the determination of nystatin in human saliva (UV and fluorescence detection). A reversed-phase Luna C18 column (25 degrees C), with a mobile phase of MeOH, H2O, and DMF (70:20:10, v/v/v), and a flow-rate of 0.8 ml/min were used. The elution time for nystatin was 5.8+/-0.2 min. Calibration curves in human saliva were linear from 0.78 to 50 microg/ml. Limits of quantification were 0.78 microg/ml and 0.75 microg/ml for UV and fluorescence detection, respectively. The accuracy and precision values of intra- and inter-day variation studies were within acceptable limits, according to FDA guidelines. The described method has proved to be useful to give accurate measurements of nystatin in real samples.

Drug release from carbomer:carbomer sodium salt matrices with potential use as mucoadhesive drug delivery system.

In vitro mucoadhesion, water uptake, and drug release of nystatin (N) from matrices of carbomer (C) and lyophilized carbomer sodium salt (CNaL) mixtures were evaluated. Matrices with different ratios C:CNaL were prepared by direct compression. Commercial C as well as lyophilized powder (CL) were used. In vitro mucoadhesion increased as the proportion of C in the matrix was raised. The same effect was observed when C was replaced by CL. Matrices in which C was replaced by CL showed an increase of both water uptake and release rates. Besides, the release of N from matrices CL:CNaL exhibited a kinetics with Super Case II (n>1) mechanism. However, for C:CNaL matrices, drug release was slower and exhibited a biphasic profile with a first stage characterized by either an anomalous (n<1, for C>or=50%) or a Case II (n approximately 1.0, C<50%) mechanisms. After that period, the mechanism changed to Super Case II transport (n>1).