Formulation of Ocular In Situ Gels with Lithuanian Royal Jelly and Their Biopharmaceutical Evaluation In Vitro.

Royal jelly is a natural substance produced by worker bees that possesses a variety of biological activities, including antioxidant, anti-inflammatory, antibacterial, and protective. Although fresh royal jelly is kept at low temperatures, to increase its stability, it needs to be incorporated into pharmaceutical formulations, such as in situ gels. The aim of this study was to formulate in situ ocular gels containing Lithuanian royal jelly for topical corneal use in order to increase the retention time of the formulation on the ocular surface and bioavailability. Gels were evaluated for physicochemical characteristics (pH, rheological properties, refractive index) and in vitro drug release measuring the amount of 10-hydroxy-2-decenoic acid (10-HDA). An ocular irritation test and cell viability tests were performed using the SIRC (Statens Seruminstitut Rabbit Cornea) cell culture line. Results indicated that all the in situ gels were within an acceptable pH and refractive index range close to corneal properties. Rheology studies have shown that the gelation temperature varies between 25 and 32 °C, depending on the amount of poloxamers. The release studies have shown that the release of 10-HDA from in situ gels is more sustained than royal jelly suspension. All gel formulations were non-irritant according to the short-time exposure test (STE) using the SIRC cell culture line, and long-term cell viability studies indicated that the formulations used in small concentrations did not induce cell death. Prepared in situ gels containing royal jelly have potential for ocular drug delivery, and they may improve the bioavailability, stability of royal jelly, and formation of non-irritant ocular formulations.

MODELLING AND BIOPHARMACEUTICAL EVALUATION OF CICLOPIROX OLAMINE GELS.

The ciclopirox olamine (CPO) has a broad antimicrobial profile including dermatophytes, yeasts and is used in various pharmaceutical forms. The aim of this study is to evaluate the quality of the CPO gels according to biopharmaceutial tests in vitro and antifungal activity assay. Hydroxypropyl cellulose, chitosan and poloxamer 407 were selected as agents gelificants. The effects of gelling agent properties and concentration on the consistency and flow characteristics have been studied by rheometer. CPO release rates from gel were measured with Franz type diffusion cells. The antifungal activity of gels was tested using agar well diffusion technique. The results of the experimental study have shown that the rheological properties of the medications depend on the selected gelling agent and the amount of it. The higher amounts of CPO were released from the poloxamer 407 gels. Though all tested CPO gels showed great inhibition of Microsporn canis.

DETERMINATION OF ANTIMICROBIAL ACTIVITY OF CHLORHEXIDINE GEL.

Many researchers have advocated in recent times that antiseptic use in healing wounds should be discouraged. Antiseptics have been found to retard healing of wounds. Poloxamer 407 shows thermoreversible properties, which are of the utmost interest in optimizing drug formulation (fluid state at room temperature facilitating administration and gel state above sol-gel transition temperature, at body temperature, promoting prolonged release of pharmacological agents). Chlorhexidine, a commonly used antiseptic, is known to be less toxic on granulation cells. Acting as an antiseptic, it is an effective bactericidal agent against the most categories of microbes, including bacteria, yeast, and viruses. Objective of this study was to evaluate antimicrobial activ- ity of chlorhexidine containing poloxamer gel to Gram-positive and Gram-negative bacteria in vitro. Chlorhexidine gels and chlorhexidine aqueous solutions have different antibacterial activity to S. amis, E.faecalis, E. coli and P. aemginosa strains in vitro. It depends on concentration and dosage form of antiseptic. Study results confirmed that antimicrobial activity of gel depends on active ingredient concentration in antiseptic. The best inhibition effect for both of reference and wild-type bacteria was obtained for 1% chlorhexidine gel. Summarizing the results and assessing the characteristics of the gel ingredients, it can be suggested using chlorhexidine gels in veterinary medicine.

A Comparative Study of the Chemical Properties and Antibacterial Activity of Four Different Ozonated Oils for Veterinary Purposes.

Infectious skin diseases are quite common in veterinary medicine. These diseases can be caused by both bacteria and pathogenic fungi. Antimicrobial drugs are usually used for treatment. An alternative to these drugs could be ozonated oils with antibacterial and antifungal properties. Four different ozonated oils (linseed, hemp seed, sunflower, and olive) were tested in order to develop an optimal pharmaceutical form for the treatment of skin infections in animals. Chemical parameters such as acid and acidity value, iodine and peroxide value, viscosity, and infrared spectres were analysed. The ozonation of oils resulted in changes in their chemical composition. The antimicrobial activity of the tested oils was evaluated by determining the minimum inhibitory concentrations and zones of inhibition in agar. After ozonation, the acid content increased in all the tested oils. The highest acidity was found in linseed oil (13.00 ± 0.11 mg KOH/g; 6.1%). Hemp oil, whose acidity was also significant (second only to linseed oil), was the least acidified by ozonation (11.45 ± 0.09 mg KOH/g; 5.75%). After ozonation, the iodine value in oils was significantly reduced (45-93%), and the highest amounts of iodine value remained in linseed (47.50 ± 11.94 g Iodine/100 g oil) and hemp (44.77 ± 1.41 Iodine/100 g oil) oils. The highest number of peroxides after the ozonation of oils was found in sunflower oil (382 ± 9.8 meqO2/kg). It was found that ozonated hemp and linseed oils do not solidify and remain in liquid form when the temperature drops. The results showed a tendency for the reference strains of S. aureus, E. faecalis, and E. coli to have broader zones of inhibition (p < 0.001) than clinical strains. Overall, ozonated linseed oil had the highest antibacterial activity, and ozonated olive oil had the lowest, as determined by both methods. It was found that ozonated linseed oil was the most effective on bacteria, while the most sensitive were S. aureus ATCC 25923, MRSA, and S. pseudointermedius (MIC 13.5 mg/mL, 4.6 mg/mL, and 13.5 mg/mL, respectively, and sterile zones 20.67 ± 0.98 mm, 20.25 ± 0.45 mm, and 18.25 ± 0.45 mm, respectively). The aim and new aspect of this work is the characterisation of selected ozonated vegetable oils, especially hemp oil, according to chemical and antibacterial parameters, in order to select suitable candidates for preclinical and clinical animal studies in the treatment of bacterial or fungal skin infections in terms of safety and efficacy.

Topical antifungal bigels: Formulation, characterization and evaluation.

Bigels with antifungal substances, ciclopirox olamine and terbinafine hydrochloride, were made of hydrogel (poloxamer 407 gel) and oleogel (polyethylene and liquid paraffin mixture). Prepared bigels were found physically stable at room temperature for six months and at least four months at 40 °C. Released amount of drug decreased when oleogel concentration in the formulation increased. Release test results depended on the insertion place of active substances. The amount of released substance was highest when ciclopirox olamine was incorporated in both phases in an equal quantity, and terbinafine hydrochloride in oleogel or in hydrogel. All formulations showed great inhibition of Microsporum canis. Thus, bigels with ciclopirox olamine and terbinafine hydrochloride are a promising dosage form for topical use.

[Antimicrobial action of ammonium salts of fused heterocycles containing ortho-nitrogen]. / Kondensuotu heterociklu amonio drusku su azoto atomu ortopadetyje bakteriostatinis poveikis.

By alkylation of hexamethylenetetramine with halogenated derivatives of ketones, ethers, esters or amides of acids, alkyl- and aralkyl halides the corresponding N-monoalkylated compounds of hexamethylenetetramine were obtained. The quaternization of pyridine nitrogen in 5,6-benzoquinoline, 8-hydroxyquinoline, quinoline, 1,10-phenanthroline molecules with alkyl- or aralkylhalides was carried out. The susceptibility of Gram-positive (Streptococcus agalactiae and Staphylococcus aureus) and Gram-negative (E. coli, Salmonella cholerae suis, Salmonella enteridis Gartneri) microorganisms to synthesized quaternary ammonium salts by disc difussion method has been detected. The bacteriostatic action of 0.5-1% solutions of all compounds was assessed in comparison with benzalkonium chloride. It was shown, that the most effectiveness against all strains is possessed by quaternary hexamethylenetetramine ammonium salts, and especially salts, containing 1-propynyl- or hydroxycarbamoylmethyl radicals. The action of these two compounds against Salmonella and Streptococcus was stronger than the action of benzalkonium chloride. Susceptibility of Pseudomonas aeruginosa to these compounds were detected. It was shown, that 1% solutions of chlorides of N-(1-propynyl) hexamethylenetetramonium and N-(hydroxycarbamoylmethyl) hexamethylenetetrammonium demonstrate the same bacteriostatic action against P. aeruginosa as well as benzalkonium chloride.

Detection and molecular characterization of canine babesiosis causative agent Babesia canis in the naturally infected dog in Lithuania.

Canine babesiosis caused by Babesia canis is an emerging infectious disease in Europe. Although previously uncommon, canine babesiosis has become quite frequent in Lithuania during the past decade. In the last few years an increasing number of cases with a wide variety of clinical signs have been recorded throughout the country. In Lithuania the identification of the disease agent in veterinarian clinics is based on a microscopic analysis of size and morphology. To date, no data on the genetic characterization of Babesia species in dogs have been documented for Lithuania. A total of 123 blood samples from dogs showing clinical signs of babesiosis on the basis of veterinary examination were tested for the presence of babesial parasites. Babesia isolated from dogs were detected and characterized by nested-PCR and sequence analysis of a fragment of the 18S rRNA gene. Babesia parasites were detected in blood smears of 94 dogs (76.4%). The molecular analysis revealed the presence of B. canis in 108 dogs (87.8%). Two genotypes of B. canis were distinguished on the basis on two nucleotide (GA → AG) substitutions observed in 18S rRNA gene sequences. The results of the present study provide knowledge of the distribution of B. canis genotypes in dogs in Lithuania, and show the necessity to use a molecular analysis for an accurate diagnosis of canine babesiosis.