A NOVEL RP-HPLC METHOD FOR THE DETECTION AND QUANTIFICATION OF CLARITHROMYCIN OR SPIRAMYCIN IN BULK DRUG SAMPLES AND DOSAGE FORMS

Objective: This study was aimed at developing an HPLC method that would be suitable and sufficiently robust to analyze clarithromycin or spiramycin from bulk materials, amorphous solid dispersions as well as when included into solid dosage forms.Methods: A C8 column (250 x 4.6 mm, 5 µm) was used as stationary phase, the mobile phase consisted of 0.1 M dipotassium hydrogen orthophosphate buffer (pH 6.0) and acetonitrile in a 50:50 (% v/v) ratio. The flow rate was set to 0.5 ml/min. UV detection of 210 nm was used for clarithromycin and 232 nm for spiramycin. Ambient column and sample tray temperatures were used.Results: The method proved to be suitable for the detection of both macrolide antibiotics in bulk samples, as part of amorphous solid dispersions as well as in dosage forms. The isocratic elution was rapid. The method was validated in terms of system suitability, limits of detection (LOD), limit of quantification (LOQ), accuracy, precision, linearity, and specificity. This method showed linearity across the concentration range of 4.0–5000.0 µg/ml for both antibiotics.Conclusion: The developed method showed to be a simple and sufficiently sensitive method for the detection and quantification of either clarithromycin or spiramycin from samples that might contain even very small quantities of the antibiotics

Zebrafish behavioral response to ivermectin: Insights into potential neurological risk

Ivermectin is a well‐known and widely used anti‐parasitic drug. Recently, in vitro data suggest anti‐viral effi- cacy of the drug, albeit at much higher concentrations than currently approved. Despite warnings by several governing bodies, the (uncontrolled) human use of ivermectin has significantly increased during the COVID‐ 19 epidemic. This study thus aimed to elucidate potential neurological risk of particularly the veterinary for- mulation of ivermectin in comparison to pure ivermectin. Zebrafish eggs (1hpf) and larvae (4dpf) were exposed to a range of concentrations of either pure ivermectin (IVM) or a veterinary formulation (V‐IVM) for a period of 24 hours. Behavioral responses to both treatments were assessed at various timepoints using the pentylenete- trazol assay, the light–dark assay and a 5‐day teratogenesis protocol. In addition, dissolution rates were calcu- lated for both treatments

The validation of a simple, robust, stability-indicating rp-hplc method for the simultaneous detection of lamivudine, tenofovir disoproxil fumarate, and dolutegravir sodium in bulk material and pharmaceutical formulations

An effective analytical method is requisite to ensure the accurate identification and quantification of drug(s), either in bulk material or in complex matrices, which form part of finished pharmaceutical products. For the purpose of a pharmaceutical formulation study, it became necessary to have a simple, yet robust and reproducible reversed-phase HPLC method for the simultaneous detection and quantification of lamivudine (3TC), tenofovir disoproxil fumarate (TDF), and dolutegravir sodium (DTG) in bulk form, complex polymeric matrices, and during drug release studies. A suitable method was developed using a Kinetex® C18, 250 × 4.6 mm column as stationary phase and a mobile phase consisting of 50 : 50 v/v methanol and water with 1 mL orthophosphoric acid, with a flow rate of 1.0 mL/min and column temperature maintained at 35°C. A detection wavelength of 260 nm and an injection volume of 10 μL were used. ,e method was validated according to the International Conference on Harmonization (ICH) guideline Q2 (R1), and the parameters of linearity and range, accuracy, precision, specificity, limit of detection (LOD), limit of quantification (LOQ), robustness, and stability were all determined. Acceptable correlation coefficients for linearity (R2) of >0.998 for each of the three drugs were obtained. ,e LOD was quantified to be 56.31 μg/mL, 40.27 μg/mL, and 7.00 μg/mL for 3TC, TDF, and DTG, respectively, and the LOQ was quantified as 187.69 μg/mL, 134.22 μg/mL, and 22.5 μg/mL for 3TC, TDF, and DTG, respectively. In relation to all the determined validation parameters, this method proves to be suitable for the accurate identification and quantification of the three ARVs, either alone or in combination, as well as when incorporated into polymeric matrices. Furthermore, the method proves to be suitable to detect degradation of the compounds

Mechanochemical synthesis and physicochemical characterization of isoniazid and pyrazinamide co-crystals with Glutaric acid

The present work reports two novel pharmaceutical co-crystals; 2:1 isoniazid-glutaric acid (INHGA) and 2:1 pyrazinamide-glutaric acid (PGA). Isoniazid and pyrazinamide are key first-line drugs used for the treatment of tuberculosis. The co-crystals were produced via solid-state and solvent assisted grinding methods. Thermal characteristics of the samples were obtained using the differential scanning calorimetry, hot stage microscopy, and thermogravimetric analyses. The morphology of the powder samples by scanning electron microscopy, structural analysis by Fourier transform infrared spectroscopy and powder X-rays diffraction ensured co-crystal formation. Thermal analyses confirmed the co-crystals with new melting transitions ranging between their respective starting materials. Unique morphologies of the co-crystal particles were clear in SEM micrographs. The formation of intermolecular interactions with the co-crystal former was confirmed by the FT-IR spectral band shifting and was supported by distinct PXRD patterns of co-crystals thereby authenticating the successful co-crystal formation. In vitro solubility evaluation of the synthesized co-crystals by HPLC suggested a remarkable increase in solubility of both INH and PZA in their respective co-crystals

Zebrafish behavioral response to ivermectin : insights into potential neurological risk

Ivermectin is a well‐known and widely used anti‐parasitic drug. Recently, in vitro data suggest anti‐viral efficacy of the drug, albeit at much higher concentrations than currently approved. Despite warnings by several governing bodies, the (uncontrolled) human use of ivermectin has significantly increased during the COVID‐ 19 epidemic. This study thus aimed to elucidate potential neurological risk of particularly the veterinary formulation of ivermectin in comparison to pure ivermectin. Zebrafish eggs (1hpf) and larvae (4dpf) were exposed to a range of concentrations of either pure ivermectin (IVM) or a veterinary formulation (V‐IVM) for a period of 24 hours. Behavioral responses to both treatments were assessed at various timepoints using the pentylenetetrazol assay, the light–dark assay and a 5‐day teratogenesis protocol. In addition, dissolution rates were calculated for both treatments. Acute responses of larvae at 4–<5dpf was similar for both treatments – a transient hyperlocomotion was followed by a general hypolocomotion (ANOVA dose effect, P < 0.01). Both IVM and VIVM‐ treated larvae showed significant dose‐dependent (ANOVA dose effect, P < 0.0001) decreases in responsiveness to repeated light–dark transitions, which again was more pronounced in IVM. These effects were maintained after 24 hours of exposure. In contrast, when ivermectin was administered prior to establishment of the blood brain‐barrier in the teratogenesis protocol, V‐IVM treatment was linked to more severe activity decline on <5dpf. Differences in dissolution rates cannot account for these differences. In conclusion, current data suggest significantly higher neurological risk of a veterinary formulation of ivermectin under conditions of penetration across the blood brain‐barrier.South African NRF.http://www.elsevier.com/locate/medidam2023Pharmacolog

Exploring co-crystallisation as a technique for taste-masking of nevirapine

The bitter taste of pharmaceuticals majorly impacts patient adherence. Co-crystallisation has been proposed as a novel way for taste masking using sweetener-based co-formers, while other co-formers also have a positive effect. We hypothesise that the sweetness of the co-formers is not the key factor but rather the molecular aggregation between the drug and co-former in solution, i.e., the stronger the interaction, the better the taste masking effect. Here, we explore the solution aggregation between the bitter-tasting drug nevirapine and five co-formers by 1H NMR spectroscopy. The co-formers benzoic acid, salicylic acid and maleic acid show strong interaction with nevirapine, while glutaric acid and saccharin have weak and no interaction, respectively. The taste of the resulting co-crystal, as assessed by the electrical taste sensing system e-tongue, reveals that the bitterness of nevirapine has been covered with the co-crystal benzoic acid, maleic acid and glutaric acid but not saccharin or salicylic acid. From the taste results we deduct that both solution aggregation and the taste of the pure co-former play an important role in taste masking. It is likely that a large variety of co-formers can be used to cover bitter drugs and we show that the investigation of molecular aggregation in solution can help screen the co-formers before any in vitro or in vivo taste test

Comparative whole corona fingerprinting and protein adsorption thermodynamics of PLGA and PCL nanoparticles in human serum

Nanoparticles (NPs) based on biocompatible and biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) represent effective systems for systemic drug delivery. Upon injection into the blood circuit, the NP surface is rapidly modified due to adsorption of proteins that form a ‘protein corona’ (PC). The PC plays an important role in cellular targeting, uptake and NP bio-distribution. Hence, the study of interactions between NPs and serum proteins appears as key for biomedical applications and safety of NPs. In the present work, we report on the comparative protein fluorescence quenching extent, thermodynamics of protein binding and identification of proteins in the soft and hard corona layers of PLGA and PCL NPs. NPs were prepared via a single emulsion-solvent evaporation technique and characterized with respect to size, zeta potential, surface morphology and hydrophobicity. Protein fluorescence quenching experiments were performed against human serum albumin. The thermodynamics of serum protein binding onto the NPs was studied using isothermal titration calorimetry. Semi-quantitative analysis of proteins in the PC layers was conducted using gel electrophoresis and mass spectrometry using human serum

Assessment of the tableting properties of chitosan through wet granulation and direct compression formulations

Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2005.Chitosan is a natural polysaccharide that is obtained by the partial deacetylation of chitin, the second most abundant natural polymer. Chitosan is currently extensively utilised in various pharmaceutical and non-pharmaceutical preparations. It has found wide applicability in conventional pharmaceutical devices as a potential formulation excipient. As a pharmaceutical excipient, its main contribution seems to be as an absorption enhancer of large molecule drugs from the gastro-intestinal tract (through "tight junctions") and as a fat absorber in dietary products. Although it is present in various tablet preparations, little if any is known about the tablet ability of this versatile polymer. Characterisation of chitosan raw material revealed poor flowability, a large partide size distribution and poor compressibility. These properties provided the challenges circumvented in this study. The direct compression of chitosan indicated that the flowabillity and compressibility of the polymer were insufficient to produce acceptable tablets comprising of pure chitosan raw material. Therefore, chitosan was combined with Avicelp PH200 and Prosolvp SMCCm 90 respectively. The properties of tablets comprising of chitosan and these directly compressible fillers were compared in terms of filler concentration and mixing time. It was found that Avicelp PH200 proved to be most effective at a concentration of 30% (w/w). Furthermore, a mixing time of 10 minutes produced optimal results for all the chitosan / filler combinations. The inclusion of single dry binders was investigated to assess the suitability of dry binders as enhancers of the binding properties of chitosan raw material. Kollidon" VA-64 (co-polyvidone) and Methocep K100M hydroxypropylmethylcellulose) were combined respectively with chitosan raw material in concentrations of 4, 5, 7, 10, 15 or 20% w/w. It was evident that chitosan exhibited a significantly higher sensitivity for Kollidon' VA-64 than for Methocelp K100M. A log-linear relation between the Kollidon" VA-64 concentration and crushing strength was identified. This could be considered a significant attribute of the chitosan / Kollidon' VA-64 combination, since this correlation could be utilised to predict the crushing strength of tablets comprising of chitosan and Kollion' VA-64 at any given concentration of the binder. In comparison with the combinations containing the directly compressible fillers the formulation comprising of 20% w/w Kollidong VA-64 produced superior crushing strength and friability. Conversely, the chitosan / Methocel' K100M mixtures revealed erratic and relatively unacceptable results in terms of crushing strength and friability. However, the presence of Methocep K100M in the formulations seemed advantageous to tablet disintegration. Therefore, the combination of both binders in different concentration ratios were investigated to determine whether a combination of the dry binders would result in potentiation of the binding effect during compression and furthermore if the presence of Methocelp K100M would enhance the disintegration of the tablets. Concentration ratios of 1:1; 3:1 and 1:3 (Kollidon~ VA-64 : MethocelP K100M) were utilised during these experiments. The formulations comprising of single dry binders produced superior results compared to the formulations containing the dry binder combinations. Furthermore, it was evident that the binder combinations did not result in the potentiation of the binding effect nor did it prove advantageous in terms of tablet disintegration. Since the characterisation of chitosan raw material proved that this polymer exhibited poor flowability, the subsequent wet granulation of chitosan was investigated utilising low and high speed granulation. kollidon" VA-64 (co-polyvidone) and Methocelp K100M (hydroxypropylmethylcellulose) were the two binders utilised in concentrations of 3% and 5% w/w respectively during granulation. Wet granulation of the polymer did improve the flowabillity, however, the inherent characteristics of chitosan still affected the tabletability of the material. Therefore, the inclusion of extragranular binder was necessitated to improve the binding of chitosan granules during compression. Kollidon" VA-64 and Methocelp K100M were utilised as external binders in concentrations of 3,5,7 and 10% w/w. Generally, the granulation processes overall improved the tabletability of the polymer since it was possible to compress larger quantities of chitosan with the aid of selected binders. Kollidon~ VA-64 posed to be better suited as a granulation binder for chitosan, compared to Methocelp K100M. Dissolution studies provided a method to determine the effect(s) of chitosan as well as the included binders on drug release. Furosemide was included in selected formulations as a tracer drug. The gel-forming ability of chitosan in acidic pH evidently decreased the release rate of the incorporated drug. Dissolution profiles of all the formulations containing chitosan granules and extragranular binder indicated sustained release of furosemide (24 hour period). Since Methocelp K100M also possesses the ability to form a gel layer on contact with water or biological fluid, the production of matrix tablets was a possibility. However, it was clear that a total concentration of 15% w/w Methocel-P K100M was insufficient to achieve matrix-like dissolution profiles. The combination of chitosan and Methocel℗ KIOOM proved to be advantageous in the formulation of sustained release dosage forms. Short-term stability testing of chitosan raw material proved that the exposure of chitosan to elevated temperatures had a detrimental effect on the tabletability of the polymer. Furthermore, it was evident that lower moisture content (sorbed water) detrimentally affected the compressibility of chitosan raw material. Long-term stability testing indicated that ambient conditions could have pronounced effects on the physical properties of the raw material, chitosan tablets as well as the granules. Furthermore, the tablets comprising of Methocelp K100M revealed the most significant deterioration in terms of crushing strength and friability. In contradiction, the tablets containing Avicep PH200 revealed the most acceptable results, confirming that direct compression produced the optimal system in terms of product stability. However, the combination of chitosan with binders allows the exclusion of Avicelp PH200. However, the formulations containing binders (granulate) revealed poor stability. It could be concluded that the storage of chitosan raw material, tablets or granules should be ensured at temperatures lower that 25 "C and relative humidity not exceeding 60%. The optimisation of chitosan raw material for utilisation in tablet formulations as well as its applicability as pharmaceutical excipient was pertinently illustrated.Master

The stabilization of amorphous zopiclone in an amorphous solid dispersion

Zopiclone is a poorly soluble psychotherapeutic agent. The aim of this study was to prepare and characterize an amorphous form of zopiclone as well as the characterization and performance of a stable amorphous solid dispersion. The amorphous form was prepared by the well-known method of quenchcooling of the melt. The solid dispersion was prepared by a solvent evaporation method of zopiclone, polyvinylpyrrolidone-25 (PVP-25), and methanol, followed by freeze-drying. The physico-chemical properties and stability of amorphous zopiclone and the solid dispersion was studied using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), hot-stage microscopy (HSM), X-ray diffractometry (XRD), solubility, and dissolution studies. The zopiclone amorphous solid-state form was determined to be a fragile glass; it was concluded that the stability of the amorphous form is influenced by both temperature and water. Exposure of amorphous zopiclone to moisture results in rapid transformation of the amorphous form to the crystalline dihydrated form. In comparison, the amorphous solid dispersion proved to be more stable with increased aqueous solubilityNorth-West University, South Africa (Potchefstroom Campus) as well as the National Research Foundation (NRF) of South Afric