Micro- and nanostructured emulsion systems based on polyhydroxy surfactants for aceclofenac delivery into/through the skin using chemical penetration enhancers and microneedles

Imajući na umu ograničenu biološku raspoloţivost i posledično terapijski efekat nesteroidnih antiinflamatornih lekova (NSAIL) primenjenih na koţi, cilj doktorske disertacije bio je razvoj, optimizacija i sveobuhvatna fizičko-hemijska i biofarmaceutska karakterizacija ulje-u-vodi nanoemulzija, kao i konvencionalnih (mikrostrukturiranih) emulzionih sistema (podloga) na bazi prirodnih polihidroksilnih surfaktanata (saharozni estri, alkil poliglukozidni (APG) emulgator) kao nosača za poboljšanu (trans)dermalnu isporuku aceklofenaka (model lekovita supstanca iz grupe NSAIL). Preciznije, cilj je bio da se primenom različitih in vitro i in vivo metoda dobije uvid u uticaj varijacija u sastavu formulacije svakog od tipova odabranih nosača (tradicionalni vs. surfaktanti novije generacije, prisustvo vs. odsustvo hemijskih pojačivača penetracije) na dermalnu raspoloţivost aceklofenaka, kao i da se proceni potencijalni značaj primene naprednih sistema, kao što su nanoemulzije, u odnosu na emulzione sisteme koji se jednostavno mogu izraditi u uslovima apoteke. Dodatno, posebno značajno je bilo proceniti da li se kombinovanom primenom nanoemulzija i predtretmana koţe čvrstim mikroiglama, kao fizičkim pojačivačima penetracije, moţe obezbediti poboljšana isporuka aceklofenaka u koţu, odnosno, kroz koţu u sistemsku cirkulaciju. Rezultati sprovedenih istraţivanja nedvosmisleno su ukazali da se primenom kombinovanog smeša-proces eksperimentalnog dizajna mogu uspešno izraditi nanoemulzije aceklofenaka zadovoljavajućih fizičko-hemijskih karakteristika, dugoročne stabilnosti i iritacionog profila korišćenjem biokompatibilnih emulgatora, kao što su lecitin iz jajeta i saharozni estri (prevashodno saharoza palmitat). Dalje, rezultati dobijeni in vitro ispitivanjem oslobaĎanja/permeacije kroz sintetsku membranu/koţu uha svinje, kao i primenom in vitro/in vivo tape stripping metode (sve metode najpre su podvrgnute optimizaciji) ukazali su na superiornost razvijenih nanoemulzija u pogledu isporuke aceklofenaka u/kroz koţu u odnosu na ispitivane mikrostrukturirane emulzione sisteme, istovremeno ukazujući na značajnu ulogu sastava smeše surfaktanata upotrebljenih za stabilizaciju nanoemulzija u isporuci aceklofenaka u/kroz koţu (saharozni estri su značajno efikasniji kao hemijski penetracioni inhenseri u odnosu na tradicionalno korišćen polisorbat 80)...Considering the limited bioavailability and consequently, therapeutic effect of nonsteroidal anti-inflammatory drugs (NSAID) applied on the skin, the aim of present doctoral dissertation was to develop oil-in-water nanoemulsions and conventional (microstructured) emulsions (bases) based on natural polyhydroxy surfactants (sucrose esters, alkyl polyglucoside (APG) emulsifier) as carriers for improved (trans)dermal delivery of aceclofenac (model NSAID) and to comprehensively evaluate their physicochemical and biopharmaceutical properties. Precisely, the present work aimed to evaluate the effect of variations in formulation composition of each selected emulsion system (traditional vs. novel surfactants, presence vs. absence of chemical penetration enhancers) on dermal availability of aceclofenac using different in vitro and in vivo pharmacokinetic-based methods, and thus, to estimate the usefulness of applying the advanced carriers, such as nanoemulsions, compared to the emulsions that can be easily prepared in a pharmacy. Additionally, it was interesting to evaluate whether the combined use of developed nanoemulsions and skin pretreatment with solid stainless steel microneedles (as a physical penetration enhancer) may facilitate aceclofenac delivery into the skin, and/or through the skin into the systemic circulation. Obtained results unequivocally indicated that it was possible to prepare, with the aid of combined mixture-process experimental design, aceclofenac-loaded nanoemulsions with satisfying physicochemical properties, long-term stability and skin irritation profile, using biocompatible emulsifiers, such as egg lecithin and sucrose esters (primarily sucrose palmitate). Furthermore, results obtained using in vitro release/skin permeation tests through the synthetic membrane/pig ear skin as well as in vitro/in vivo tape stripping (all submitted through careful optimization) proved the superiority of developed nanoemulsions regarding aceclofenac delivery into/through the skin compared to tested microstructured emulsion systems, simultaneously singling out the surfactant mixture employed for nanoemulsion stabilization as a key factor for efficient aceclofenac delivery into/through the skin (sucrose esters are more efficient as the chemical penetration enhancers than traditionally used polysorbate 80)..

The implications of regulatory framework for topical semisolid drug products: From critical quality and performance attributes towards establishing bioequivalence

Due to complex interdependent relationships affecting their microstructure, topical semisolid drug formulations face unique obstacles to the development of generics compared to other drug products. Traditionally, establishing bioequivalence is based on comparative clinical trials, which are expensive and often associated with high degrees of variability and low sensitivity in detecting formulation differences. To address this issue, leading regulatory agencies have aimed to advance guidelines relevant to topical generics, ultimately accepting different non-clinical, in vitro/in vivo surrogate methods for topical bioequivalence assessment. Unfortunately, according to both industry and academia stakeholders, these efforts are far from flawless, and often upsurge the potential for result variability and a number of other failure modes. This paper offers a comprehensive review of the literature focused on amending regulatory positions concerning the demonstration of (i) extended pharmaceutical equivalence and (ii) equivalence with respect to the efficacy of topical semisolids. The proposed corrective measures are disclosed and critically discussed, as they span from mere demands to widen the acceptance range (e.g., from 10% to 20%/25% for rheology and in vitro release parameters highly prone to batch-to-batch variability) or reassess the optimal number of samples required to reach the desired statistical power, but also rely on specific data modeling or novel statistical approaches

Međuodnos konkurentnih leksičkih jedinica i imeničkih sintagmi u srpskom jeziku ; Relationship between competitive lexical units and nouns syntagms in the Serbian language ; Взаимосвязь конкурирующих синтагм в сербском языке

Предмет истраживања јесте конкуренција семантички еквивалентних синтаксичкихјединица − лексичких јединица (именица и поименичених придева) и именичких синтагми.Основни циљ истраживања јесте опис њихових семантичко-синтаксичких карактеристика, теанализа њиховог међуодноса на синтагматском и парадигматском плану.Коришћена је структурална метода, и то лексичко-синтаксичко-семантичка, а додатнои колокацијска и функционалностилска метода.Истраживање је спроведено на разуђеном функционалностилском корпусу, од писанихизвора различитих жанрова, грађе ексцерпиране из описних речника српског језика, изелектронског корпуса, те је допуњена језичким материјалом прикупљеним с интернета, свебсајтова и интернет форума.Истраживању се примарно прилази са творбеног, синтаксичког и стилског аспекта. Ураду се указује на то да је одабир између конкурентних јединица условљен ограничењимакаква су семантичка, творбена и синтаксичка. Притом, да до разједначавања конкурентнихоблика долази пре свега приликом њихове напоредне употребе и у стручном дискурсу.Показује се фаворизање једног облика у односу на други у одређеној врсти текста или уфункционалном стилу. Такође, испоставља се да је дистрибуција конкурентних облика у везиса прагматичкo-стилским критеријумима, односно са различитим комуникативним потребама(онеобичавање, истицање одређене семантичке компоненте, успостављање лексичке кохезијеитд. ), као и са критеријумом референцијалности и линеаризацијом. Даје се и прегледпродуктивних и оказионалних синтагматских модела конкурентних лексичким јединицама.Такође се показује да се семантика и функција независног члана модификује унутар иван плеонастичних деминутивних и полуконгруентних синтагми.Subject of the research is a competition of semantically equivalent syntactic units - lexicalunits (nouns and noun adjectives) and noun phrases. Basic aim of the research is to describe theirsemantic-syntactic characteristics, and to analyze their interrelationship on the syntagmatic and paradigmatic level.The structural method was used, namely the lexical-syntactic-semantic method, and additionally the collocation and functional-stylistic method.The research was conducted on a diverse functional-stylistic corpus, from written sources ofvarious genres, material excerpted from descriptive dictionaries of the Serbian language, from theelectronic corpus, and supplemented with language material collected from the Internet, websitesand Internet forums.The research is primarily approached from the creative, syntactic and stylistic aspects. Thepaper points out that the choice between competing units is conditioned by limitations such assemantic, creative and syntactic. At the same time, the equalization of competing forms occurs primarily during their parallel use and in professional discourse. It shows the favoring of one formover another in a particular type of text or in a functional style. Also, it turns out that thedistribution of competing forms is related to pragmatic-stylistic criteria, ie different communicativeneeds (disabling, emphasizing a certain semantic component, establishing lexical cohesion, etc.), aswell as the criterion referentiality and linearization. An overview of productive and occasional syntagmatic models competing with lexical units is also given.It is also shown that the semantics and function of the independent member are modifiedinside and outside the pleonastic diminutive and semi-congruent syntagms

Simultaneous Physico-Mechanical and In Vivo Assessment towards Factual Skin Performance Profile of Topical Polymeric Film-Forming Systems

Topical film-forming systems (FFS) change drastically after solvent displacement, therefore indicating their skin metamorphosis/transformation as a property of special regulatory and research interest. This paper deals with the lack of suitable characterization techniques, suggesting a set of methods able to provide a comprehensive notion of FFS skin performance. After screening the physico-chemical, mechanical and sensory properties of FFS and resulting films, an elaborate three- phase in vivo study was performed, covering skin irritation, friction and substantivity. Upon removal of 24-hour occlusion, no significant change in erythema index was observed, while the film-former type (cellulose ether, acrylate and/or vinyl polymer) affected transepidermal water loss (TEWL); hydrophobic methacrylate copolymer-based samples decreased TEWL by 40–50%, suggesting a semi-occlusive effect. Although both the tribological parameters related to the friction coefficient and the friction curve’s plateau provided valuable data, their analysis indicated the importance of the moment the plateau is reached as the onset of the secondary formulation, while the tertiary state is still best described by the completion of the film’s drying time. The final part of the in vivo study proved the high in-use substantivity of all samples but confirmed the optimal 4:1 ratio of hydrophobic cationic and hydrophilic polymers, as indicated during early physico-mechanical screening

Development of suitable working Protocol for in vitro Tape Stripping: A Case Study with biocompatible Aceclofenac-loaded topical Nanoemulsions

Considering the numerous organizational and legislative issues associated with in vivo studies, the present study aimed to develop in vitro tape stripping protocol that could serve as a prospective technique for skin penetration studies. The research was mainly focused on the suitability of transepidermal water loss (TEWL) measurements, as a barrier integrity test for porcine ear skin subjected to freezing/thawing procedure, as well as on the selection of the most suitable device for pressing adhesive tapes onto the porcine ear surface during skin stripping procedure. Obtained results suggest that TEWL measurements were able to detect the damage of the stratum corneum (SC) caused by physical impairment (using adhesive tapes) and tissue degradation/dehydration (prolonged storage at –20ºC/ambient conditions). Penetration profiles of aceclofenac from nanoemulsions based on sucrose esters or polysorbate 80 as coemulsifiers, obtained in vitro (using a roller as pressure device), were in a good agreement with data obtained in vivo on humans, supporting the use of developed in vitro tape-stripping protocol in skin formulation development and optimization

Efficient Development of Green Emulsifier/Emollient-Based Emulsion Vehicles: From RSM Optimal Experimental Design to Abridged In Vivo Assessment

Since natural-origin, sustainable ingredients are preferred by modern consumers, novel emulsifiers and emollients keep entering the market. This study hypothesizes that a combination of in silico, instrumental tools and simplified sensory studies could be used to efficiently characterize emulsions in a shorter timeframe. A total of 22 rather simple o/w emulsions were prepared by a time/energy-saving emulsification process. A natural mixed emulsifier (Lauryl Glucoside/Myristyl Glucoside/Polyglyceryl-6 Laurate) and two emollients (both with INCI name C15–19 Alkane) were used. The performed D-optimal experimental design within the response surface method (RSM) significantly narrowed down the number of samples about to enter the stage of texture, friction and sensory studies to the samples comprising 30% of a respective Emogreen emollient and 2% or 3% of the emulsifier. The sample comprising 2% emulsifier/30% Emogreen® L15 showed significantly higher firmness (42.12 mN) when compared to the one with 2% emulsifier/30% Emogreen® L19 (33.62 mN), which was somewhat unexpected considering the emollients’ inherent viscosity values (4.5 mPa·s for L15 and 9 mPa·s for L19). The sample with 2% emulsifier/30% Emogreen® L19 managed to maintain the lowest friction, while the one with 3% emulsifier/30% Emogreen® L19 released its full lubricating potential in the second part of the measurement (30–60 s). The obtained results revealed the strengths and weaknesses of each formulation, narrowing down their possible applications in the early development stage

MICROBIOLOGICAL CRITERIA IN THE MANUFACTURE OF PASTEURIZED MILK

The process hygiene criterion is a microbiological criterion that applies to the process offood production and processing and indicates the proper functioning of the production process byrepresenting the value of the contamination above which corrective measures are taken to maintainthe process hygiene. Pasteurized milk is a product obtained by heat treatment of raw milk at atemperature of 63° C for 30 minutes or 72° C for 15 seconds. Pasteurization has two purposes, thefirst one is to elimination of all pathogenic microorganisms, and the second is to reduce the numberof saprophytic microorganisms, which prolongs the shelf life without changing the nutritional andbiological value of the milk.The aim of the study is to examine the safety of pasteurized milk and the conditions of hygiene inthe production process based on the results of the examination of pasteurized milk on the criteria ofhygiene in the production process, as well as to develop a proposal for the recommendedmicroorganisms to be tested in the process of the production of pasteurized milk.Samples of pasteurized milk come from a pasteurizing plant that purchases milk from the territoryof Republika Srpska, and were sampled in the six-month period (January-June), within self-controland official control. For microbiological testing of raw milk, standard BAS ISO methods were used.The results of pasteurized milk testing in relation to the hygiene criteria in the production processare satisfactory in relation to the Rulebook on Microbiological Criteria for Food. The results of selfcontrolon the recommended microbiological criteria in the process of obtaining pasteurized milk,which are given in the Guideline on the Application of Microbiological Criteria for Food, aresatisfactory in relation to the finding of Listeria monocytogenes, Salmonella spp. and coagulasepositive staphylococci, and unsatisfactory for a number of microorganisms.The results of official controls in the production process of pasteurized milk are unsatisfactory dueto the increased number of microorganisms in 12.50% of the samples. 22.20% of pasteurized milksamples had the number of microorganisms larger than 105CFU/ml within self-control and officialcontrols. Examination of pasteurized milk in the self-control of the production process should beperformed on enterobacteria and the total count of microorganisms, and in the interpretation of theresults the recommended limit values from the Guideline on the application of microbiologicalcriteria for food should be used

Quality and autochthonous microbiota of dry-cured sheep ham from western Balkans

Dry-cured sheep ham is a traditional product of Western Balkans. It is prepared by dry curing specially treated whole sheep carcasses which are smoked for a short time and spontaneously fermented in air under uncontrolled conditions. Lactic acid bacteria (LAB) play a key role in defining the quality and organoleptic characteristics of dry-cured sheep ham. The aim of this research was to investigate the chemical parameters of drycured sheep ham quality as well as the isolation and preliminary categorization of LAB. To this end, samples of dry-cured sheep ham were obtained from nine sheep of average age of about five years, from three households from the geographical area Sjenica (Western Serbia). Physicochemical analysis has determined the content of water, protein, fat, mineral matter, water activity and pH values in the product. Phenotypic characterization of LAB isolated from dry-cured sheep ham was based on the general morphology of the cell, physiological tests and sugar fermentation patterns of LAB isolates. 124 isolates of LAB were preliminary identified as Lactobacillus curvatus , Lactobacillus sakei and Enterococcus faecium . Chemical analysis confirmed a harmonious relationship between the quality parameters of dry-cured sheep ham.Author's versio

Parenteral Lipid-Based Nanoparticles for CNS Disorders: Integrating Various Facets of Preclinical Evaluation towards More Effective Clinical Translation

Contemporary trends in combinatorial chemistry and the design of pharmaceuticals targeting brain disorders have favored the development of drug candidates with increased lipophilicity and poorer water solubility, with the expected improvement in delivery across the blood–brain barrier (BBB). The growing availability of innovative excipients/ligands allowing improved brain targeting and controlled drug release makes the lipid nanocarriers a reasonable choice to overcome the factors impeding drug delivery through the BBB. However, a wide variety of methods, study designs and experimental conditions utilized in the literature hinder their systematic comparison, and thus slows the advances in brain-targeting by lipid-based nanoparticles. This review provides an overview of the methods most commonly utilized during the preclinical testing of liposomes, nanoemulsions, solid lipid nanoparticles and nanostructured lipid carriers intended for the treatment of various CNS disorders via the parenteral route. In order to fully elucidate the structure, stability, safety profiles, biodistribution, metabolism, pharmacokinetics and immunological effects of such lipid-based nanoparticles, a transdisciplinary approach to preclinical characterization is mandatory, covering a comprehensive set of physical, chemical, in vitro and in vivo biological testing