Predicting in vivo absorption of chloramphenicol in frogs using in vitro percutaneous absorption data.

BACKGROUND: Infectious disease, particularly the fungal disease chytridiomycosis (caused by Batrachochytrium dendrobatidis), is a primary cause of amphibian declines and extinctions worldwide. The transdermal route, although offering a simple option for drug administration in frogs, is complicated by the lack of knowledge regarding percutaneous absorption kinetics. This study builds on our previous studies in frogs, to formulate and predict the percutaneous absorption of a drug for the treatment of infectious disease in frogs. Chloramphenicol, a drug with reported efficacy in the treatment of infectious disease including Batrachochytrium dendrobatidis, was formulated with 20% v/v propylene glycol and applied to the ventral pelvis of Rhinella marina for up to 6 h. Serum samples were taken during and up to 18 h following exposure, quantified for chloramphenicol content, and pharmacokinetic parameters were estimated using non-compartmental analysis. RESULTS: Serum levels of chloramphenicol reached the minimum inhibitory concentration (MIC; 12.5 µg.mL- 1) for Batrachochytrium dendrobatidis within 90-120 min of exposure commencing, and remained above the MIC for the remaining exposure time. Cmax (17.09 ± 2.81 µg.mL- 1) was reached at 2 h, while elimination was long (t1/2 = 18.68 h). CONCLUSIONS: The model, based on in vitro data and adjusted for formulation components and in vivo data, was effective in predicting chloramphenicol flux to ensure the MIC for Batrachochytrium dendrobatidis was reached, with serum levels being well above the MICs for other common bacterial pathogens in frogs. Chloramphenicol's extended elimination means that a 6-h bath may be adequate to maintain serum levels for up to 24 h. We suggest trialling a reduction of the currently-recommended continuous (23 h/day for 21-35 days) chloramphenicol bathing for chytrid infection with this formulation.

Agar/κ-carrageenan/montmorillonite nanocomposite hydrogels for wound dressing applications.

In this study, agar/κ-carrageenan/montmorillonite (MMT) hydrogels were prepared to examine their usability as wound dressing materials and to see the effect of MMT amount on some properties of agar/κ-carrageenan hydrogel materials. Hydrogels were characterized by SEM-EDX, TEM and DSC analyses. By increasing the MMT content within hydrogel matrix from 0% to 5%, the decomposition temperature of the hydrogel material was increased from 256.6 °C to 262.1 °C. Swelling amount of hydrogels in d-glucose solution (2682%) was found to be much higher compared with other physiological solutions such as physiological saline solution (937%), synthetic urine solution (746%) and simulated wound fluid (563%). The release studies of analgesic lidocaine hydrochloride (LDC) and antibiotic chloramphenicol (CLP) drugs from hydrogel systems demonstrated that the release amount of LDC and CLP from hydrogels could be controlled by MMT amount within hydrogel matrix. The concentrations of drugs within hydrogel sample stored at 4 °C for 6 months did not exhibit a significant change. Hydrogel materials containing CLP exhibited good antibacterial activity against E. coli and S. aureus. Cytotoxicity test results indicated that hydrogels were biocompatible with MG-63 cells. The ultimate compressive stress of agar/κ-carrageenan hydrogel with LDC and CLP and agar/κ-carrageenan/MMT hydrogel including 5% MMT with LDC and CLP was measured as 38.30 kPa and 47.70 kPa, respectively. The experimental results revealed that prepared agar/κ-carrageenan and agar/κ-carrageenan/MMT hydrogels have great potential for wound care applications.

Pharmacokinetics of multiple doses of chloramphenicol in fed adult horses.

To the authors' knowledge, there have been no studies evaluating the pharmacokinetics of chloramphenicol administered orally to horses at the currently recommended dose of 50 mg/kg PO q6 h for multiple days. The published antimicrobial susceptibility breakpoint is 8.0 ug/mL; it is unknown if this concentration is achievable at the recommended dose rate in horses. The aim of this prospective multi-dose pharmacokinetic study was to perform pharmacokinetic analysis of chloramphenicol after multiple doses. The authors hypothesize that the antimicrobial susceptibility breakpoint will not be reached. Seven healthy adult horses were administered 50 mg/kg chloramphenicol base tablets PO q6 h for 4 days. Blood was collected via venipuncture daily at 4 and 6 h after administration for the first 15 doses. After the 16th dose, an IV catheter was aseptically placed in the right jugular vein and blood was collected at regular intervals for pharmacokinetic analysis. Maximum chloramphenicol concentration was variable between horses (2.1-42.7 µg/mL). The highest average chloramphenicol concentration was just below the susceptibility breakpoint at 7.7 ug/mL while the lowest was well below the breakpoint at 1.5 ug/mL. On average, the time above 8.0 µg/mL was 75 min, considerably less than the recommended 50% of the dosing interval. When chloramphenicol is administered at a dose of 50 mg/kg PO q6 h in horses, the highest reliably achievable steady state concentration for at least half of the dosing interval is 2.0 µg/mL. The established susceptibility breakpoint of 8.0 ug/mL is not achievable in adult horses, and should be re-evaluated.

Potentiation of Antibiotics by a Novel Antimicrobial Peptide against Shiga Toxin Producing E. coli O157:H7.

Infection with Shiga toxin-producing Escherichia coli (STEC) results in hemorrhagic colitis and can lead to life-threatening sequelae including hemolytic uremic syndrome (HUS). Conventional treatment is intravenous fluid volume expansion. Antibiotic treatment is contraindicated, due in part to the elevated risk of HUS related to increased Shiga toxin (Stx) release associated with some antibiotics. Given the lack of effective strategies and the increasing number of STEC outbreaks, new treatment approaches are critically needed. In this study, we used an antimicrobial peptide wrwycr, previously shown to enhance STEC killing without increasing Stx production, in combination with antibiotic treatments. Checkerboard and time-kill assays were used to assess peptide wrwycr-antibiotic combinations for synergistic STEC killing. Cytotoxicity and real-time PCR were used to evaluate Stx production and stx expression, respectively, associated with these combinations. The synergistic combinations that showed rapid killing, no growth recovery and minimal Stx production were peptide wrwycr-kanamycin/gentamicin. Transmission electron microscopy revealed striking differences in bacterial cell morphology associated with various treatments. This study provides proof of principle for the design of an antibiotic-peptide wrwycr combination effective in killing STEC without enhancing release of Shiga toxins. It also offers a strategy for the repurposing of antibiotics for treatment of STEC infection.

Identification of chloramphenicol in human hair leading to a diagnosis of factitious disorder.

Introduction: Chloramphenicol (2,2-dichloro-N-[1,3-dihydroxy-1-(4-nitrophenyl)porpan-2-yl]acetamide) is a bacteriostatic antibiotic of the phenicolated family, used in the past to treat meningitis, plague, cholera, or typhoid fever. Treatment with chloramphenicol can have life threatening side effects, the most serious of which is aplastic anemia, which may be fatal. For this reason, the antibiotic was removed from the French market in 2008.Case report: In this paper, the authors report the case of a woman consuming chloramphenicol possibly in the context of factitious disorder. After a capsule containing chloramphenicol was discovered in her hospital bed, a hair specimen (about 16 cm, brown, not oriented) was collected and sent to the toxicological laboratory in order to document exposure to chloramphenicol.Results: The drug was identified in the hair specimen of the subject at 13.7 ng/mg.Discussion: Identification of chloramphenicol in hair has not been reported in the literature. As consequence, the interpretation of the concentration, the dosage and the frequency of abuse are difficult to establish.Conclusion: Given the context, physicians considered the case as a possible factitious disorder, thus being a unique observation of using chloramphenicol in such a context.

The new ophthalmic formulation for infection control by combining collagen/gelatin/alginate biomaterial with liposomal chloramphenicol.

Eye drops are a conventional method of drug delivery to the eye, accounting for 90% of currently accessible ophthalmic formulations. The major problem with eye drop treatments is rapid pre-corneal drug loss. Furthermore, the need for frequent administration of eye drops can profoundly affect the quality of life of ophthalmological patients. In the current study, we developed a liposomal nanoparticle encapsulated with chloramphenicol mixed with biodegradable materials against ophthalmological disease. We first established a protocol for chloramphenicol (CAP) loaded into liposomal nanoparticle (LipoCAP). We also established the collagen/gelatin/sodium alginate (CGA) as the component of biodegradable polymers and calibrated the novel drug-releasing formulation. Finally, we combined LipoCAP with CGA to generate an 8-h degradable ophthalmic chloramphenicol gel, CGA-LipoCAP-8. CGA-LipoCAP-8 reached the effective working concentration in 75 min and prolonged the drug-releasing time for at least 12 h. In addition, CGA-LipoCAP-8 could stably and continuously inhibit E. coli proliferation. The inhibiting phenomenon was more pronounced over time. Furthermore, there were no significant toxicities observed when CGA-LipoCAP-8 co-cultured with ocular epithelial cells. In conclusion, CGA-LipoCAP-8 achieved effective CAP dose concentrations in a short time and sustained CAP release for a prolonged period. Our results provide an innovative concept in relation to novel drug-release formulations, with safety and efficiency supporting use in future treatments for ophthalmological diseases.

Comparative analysis of the effects of honey, copaiba oil-resin and a commercial product (fibrinolysin, deoxyribonuclease and chloramphenicol) on second intention healing, in rats. / Análise comparativa dos efeitos do mel, do óleo-serina de copaíba e de um produto comercial (fibrinolisina, desoxirribonuclease e cloranfenicol) na cicatrização por segunda intenção, em ratos.

OBJECTIVE: to compare the healing by second intention under the effects of topical application of honey, copaíba oil-resin and a commercial product (fibrinolysin, deoxyribonuclease and chloramphenicol) with a control group in rats. METHODS: we carried out a skin resection, 1cm in diameter, on the back of 40 rats allocated to four groups of ten animals. All wounds were cleaned daily with 2ml of 0.9% NaCl solution. The first group (control - GC) was restricted to such procedure. In the wounds of the second (GM), third (GO) and fourth groups (GF), after cleaning, we respectively applied 1ml of honey, 1ml of copaíba oil-resin and 1ml of cream containing fibrinolysin, deoxyribonuclease and chloramphenicol. The wounds were occluded with sterile gauze. Immediately after the incision and on days three, seven and 14 of the experiment, the wounds were copied and contraction was analyzed using planimetry. After euthanasia, we histologically evaluated the inflammatory reaction and collagen in the scars. RESULTS: the reduction of the wound area of GM (p=0.003), GO (p=0.011) and GF (p=0.002) were higher than the GC. The amount of type-I collagen present in GM and GO was higher than in GC and GF groups (p<0.05). There was a predominance of chronic inflammatory stage in GM (p=0.004), GO (p<0.001) and GF (p=0.003) when compared with GC. CONCLUSION: the topical use of honey and copaíba oil-resin increases wound contraction, the presence of type-I collagen and accelerates healing.

OBJETIVO: comparar a cicatrização, por segunda intenção, sob os efeitos da aplicação tópica de mel, óleo-resina de copaíba e um produto comercial (fibrinolisina, desoxirribonuclease e cloranfenicol) a um grupo controle, em ratos. MÉTODOS: ressecção de pele, com 1cm de diâmetro, foi realizada no dorso de 40 ratos alocados em quatro grupos de dez animais. Todas as feridas foram limpas, diariamente, com 2ml de solução de NaCl 0,9%. O primeiro grupo (controle - GC) ficou restrito a tal procedimento. Nas feridas do segundo (GM), terceiro (GO) e quarto grupos (GF), após limpeza, aplicou-se, respectivamente, 1ml de mel, 1ml de óleo-resina de copaíba e 1ml de creme contendo fibrinolisina, desoxirribonuclease e cloranfenicol. Ocluíram-se as feridas com gaze estéril. Imediatamente após a incisão e nos dias três, sete e 14 do experimento, as feridas foram copiadas e, usando planimetria, analisou-se a contração. Após a eutanásia, a histologia foi utilizada para avaliação da reação inflamatória e do colágeno nas cicatrizes. RESULTADOS: a redução da área da ferida do GM (p=0,003), GO (p=0,011) e GF (p=0,002) foram superiores ao do GC. A quantidade de colágeno tipo I presente no GM e no GO foi superior aos grupos GC e GF (p<0,05). Houve predominância do estágio inflamatório crônico no GM (p=0,004), GO (p<0,001) e GF (p=0,003) quando comparados ao GC. CONCLUSÃO: o uso tópico do mel e do óleo-resina de copaíba aumenta a contração da ferida, a presença de colágeno tipo I e acelera a cicatrização.

Intra-articular Injection of Chloramphenicol Reduces Articular Cartilage Degeneration in a Rabbit Model of Osteoarthritis.

BACKGROUND: Osteoarthritis (OA) is characterized by degeneration of articular cartilage. Studies have found that enhancement of autophagy, an intracellular catabolic process, may limit the pathologic progression of OA. Chloramphenicol is a potent activator of autophagy; however, the effects of chloramphenicol on articular cartilage are unknown. QUESTIONS/PURPOSES: Using human OA knee chondrocytes in vitro, we asked, does chloramphenicol (1) activate autophagy in chondrocytes; (2) protect chondrocytes from IL-1ß-induced apoptosis; and (3) reduce the expression of matrix metallopeptidase (MMP)-13 and IL-6 (markers associated with articular cartilage degradation and joint inflammation). Using an in vivo rabbit model of OA, we asked, does an intra-articular injection of chloramphenicol in the knee (4) induce autophagy; (5) reduce OA severity; and (6) reduce MMP-13 expression? METHODS: Human chondrocytes were extracted from 10 men with OA undergoing TKA. After treatment with 25 µg/mL, 50 µg/mL, or 100µg/mL chloramphenicol, the autophagy of chondrocytes was detected with Western blotting, transmission electron microscopy, or an autophagy detection kit. There were four groups in our study: one group was untreated, one was treated with 100 µg/mL chloramphenicol, another was treated with 10 ng/mL of IL-1ß, and the final group was treated with 10 ng/mL of IL-1ß and 100 µg/mL of chloramphenicol. All groups were treated for 48 hours; cell apoptosis was detected with Western blotting and flow cytometry. Inflammation marker IL-6 in the cell culture supernatant was detected with an ELISA. Articular cartilage degradation-related enzyme MMP-13 was analyzed with Western blotting. A rabbit model of OA was induced by intra-articular injection of type II collagenase in 20 male 3-month-old New Zealand White rabbits' right hind leg knees; the left hind leg knees served as controls. Rabbits were treated by intra-articular injection of saline or chloramphenicol once a week for 8 weeks. Autophagy of the articular cartilage was detected with Western blotting and transmission electron microscopy. Degeneration of articular cartilage was analyzed with Safranin O-fast green staining and the semi-quantitative index Osteoarthritis Research Society International (OARSI) grading system. Degeneration of articular cartilage was evaluated using the OARSI grading system. The expression of MMP-13 in articular cartilage was detected with immunohistochemistry. RESULTS: Chloramphenicol activated autophagy in vitro in the chondrocytes of humans with OA and in an in vivo rabbit model of OA. Chloramphenicol inhibited IL-1-induced apoptosis (flow cytometry results with chloramphenicol, 25.33 ± 3.51%, and without chloramphenicol, 44.00 ± 3.61%, mean difference, 18.67% [95% CI 10.60 to 26.73]; p = 0.003) and the production of proinflammatory cytokine IL-6 (ELISA results, with chloramphenicol, 720.00 ± 96.44 pg/mL, without chloramphenicol, 966.67 ± 85.05 pg/mL; mean difference 74.24 pg/mL [95% CI 39.28 to 454.06]; p = 0.029) in chondrocytes. After chloramphenicol treatment, the severity of cartilage degradation was reduced in the treatment group (OARSI 6.80 ± 2.71) compared with the control group (12.30 ± 2.77), (mean difference 5.50 [95% CI 1.50 to 9.50]; p = 0.013). Furthermore, chloramphenicol treatment also decreased the production of MMP-13 in vitro and in vivo. CONCLUSIONS: Chloramphenicol reduced the severity of cartilage degradation in a type II collagen-induced rabbit model of OA, which may be related to induction of autophagy and inhibition of MMP-13 and IL-6. CLINICAL RELEVANCE: Our study suggests that an intra-articular injection of chloramphenicol may reduce degeneration of articular cartilage and that induction of autophagy may be a method for treating OA. The animal model we used was type II collagen-induced OA, which was different from idiopathic OA and post-traumatic OA. Therefore, we need to use other types of OA models (idiopathic OA or a surgically induced OA model) to further verify its effect, and the side effects of chloramphenicol also need to be considered, such as myelosuppression.

Investigation of chloramphenicol release from PVA/CMC/HEA hydrogel using ion beam analysis, UV and FTIR techniques.

PVA/CMC/HEA based cross-linked hydrogels were synthesized. These were utilized as matrix chloramphenicol drug releasing systems. Combination of different analytical techniques was applied to understand drug releasing process. Ion beam analysis (IBA) measurements, namely micro-PIXE analysis, were applied to gain information regarding spatial distribution of chloramphenicol within the system. Independent complement measurements utilizing UV and pore volume measurements were also employed to additionally characterize and verify the experimental findings obtained by IBA techniques. FTIR was utilized to both characterize and justify the releasing behavior of the crosslinked systems. Comprehensive literature comparison between different analytical methods has been reviewed.

Comparison of the Efficacy of Topical Chloramphenicol 0.5%-Betamethasone 0.2% (CB) and CB Associated with Sodium Hyaluronate/Trehalose/Carbomer Gel Following Strabismus Surgery.

Purpose: To compare the efficacy of topical chloramphenicol 0.5%-betamethasone 0.2% (CB) and CB associated with sodium hyaluronate/trehalose/carbomer (HTC-gel) gel following strabismus surgery. Methods: Longitudinal, single-arm, study case series analysis involved patients undergoing bilateral symmetrical horizontal strabismus surgery. One eye received CB alone and the contralateral eye CB and HTC-gel. Both treatments were instilled 3 times a day for 4 weeks postoperatively. Ocular inflammation was assessed objectively at 1 and 4 weeks by Efron scale for conjunctival redness. Foreign body sensation, burning/stinging, itching, pain, stick feeling, and blurred vision were evaluated by the numerical rating scale. Results: There were 31 patients included in the study. The mean age at presentation was 51 years (standard deviation 24, range 19-85). Conjunctival inflammatory at 1 and 4 weeks showed no statistically significant difference between the 2 treatments (P = 0.75 and P = 0.33, respectively). At 1 week postsurgery, all the subjective parameters showed a significant difference (P < 0.0001) between the 2 groups of treatment to the exclusion of "itching" and "pain" (P = 0.18 and P = 0.67, respectively) with higher scores, to the exception of "blurred vision" in the CB treatment. At 4 weeks postoperatively, no statistically significant differences between the 2 groups (P > 0.16) of treatments were observed, with the exception of the symptom "blurred vision" (0.00 vs. 1.65, CB vs. CB and HTC-gel, respectively, P < 0.0001). Conclusion: CB associated with HTC-gel seems to be an effective treatment option following strabismus surgery.

Chloramphenicol/sulfobutyl ether-ß-cyclodextrin complexes in an ophthalmic delivery system: prolonged residence time and enhanced bioavailability in the conjunctival sac.

Objective: Conventional chloramphenicol (CHL) eye drops are widely used anti-infection formulations for acute bacterial conjunctivitis. However, the therapeutic effects are limited by insufficient concentration in the conjunctival sac. Hence, the objective of this study is to formulate and develop novel CHL eye drops with improved topical concentrations by increasing the solubility and decreasing the transcorneal penetration. Research design and methods: CHL was included in the sulfobutyl ether-ß-cyclodextrin (SBE-ß-CD) using the freeze-drying method. Eye drops containing CHL/SBE-ß-CD complexes were prepared and evaluated for in vitro and in vivo studies. Results: The formation of CHL/SBE-ß-CD inclusion was confirmed by DSC, XRD, NMR, and SEM. The aqueous solubility of CHL was significantly enhanced, and the drug transcorneal penetration was inhibited after inclusion. The CHL/SBE-ß-CD displayed sustained release profiles. The tear fluid elimination kinetic study showed that the CHL/SBE-ß-CD eye drops had better ability to prolong the residence time, and significantly increase CHL concentration in the conjunctival sac. Besides, it was shown that CHL/SBE-ß-CD eye drops were nonirritating to rabbits' eyes. Conclusions: The SBE-ß-CD inclusions offer a potential alternative strategy for ocular administration of poorly water-soluble drugs in the conjunctival sac.

Análise comparativa dos efeitos do mel, do óleo-serina de copaíba e de um produto comercial (fibrinolisina, desoxirribonuclease e cloranfenicol) na cicatrização por segunda intenção, em ratos / Comparative analysis of the effects of honey, copaiba oil-resin and a commercial product (fibrinolysin, deoxyribonuclease and chloramphenicol) on second intention healing, in rats

RESUMO Objetivo: comparar a cicatrização, por segunda intenção, sob os efeitos da aplicação tópica de mel, óleo-resina de copaíba e um produto comercial (fibrinolisina, desoxirribonuclease e cloranfenicol) a um grupo controle, em ratos. Métodos: ressecção de pele, com 1cm de diâmetro, foi realizada no dorso de 40 ratos alocados em quatro grupos de dez animais. Todas as feridas foram limpas, diariamente, com 2ml de solução de NaCl 0,9%. O primeiro grupo (controle - GC) ficou restrito a tal procedimento. Nas feridas do segundo (GM), terceiro (GO) e quarto grupos (GF), após limpeza, aplicou-se, respectivamente, 1ml de mel, 1ml de óleo-resina de copaíba e 1ml de creme contendo fibrinolisina, desoxirribonuclease e cloranfenicol. Ocluíram-se as feridas com gaze estéril. Imediatamente após a incisão e nos dias três, sete e 14 do experimento, as feridas foram copiadas e, usando planimetria, analisou-se a contração. Após a eutanásia, a histologia foi utilizada para avaliação da reação inflamatória e do colágeno nas cicatrizes. Resultados: a redução da área da ferida do GM (p=0,003), GO (p=0,011) e GF (p=0,002) foram superiores ao do GC. A quantidade de colágeno tipo I presente no GM e no GO foi superior aos grupos GC e GF (p<0,05). Houve predominância do estágio inflamatório crônico no GM (p=0,004), GO (p<0,001) e GF (p=0,003) quando comparados ao GC. Conclusão: o uso tópico do mel e do óleo-resina de copaíba aumenta a contração da ferida, a presença de colágeno tipo I e acelera a cicatrização.

ABSTRACT Objective: to compare the healing by second intention under the effects of topical application of honey, copaíba oil-resin and a commercial product (fibrinolysin, deoxyribonuclease and chloramphenicol) with a control group in rats. Methods: we carried out a skin resection, 1cm in diameter, on the back of 40 rats allocated to four groups of ten animals. All wounds were cleaned daily with 2ml of 0.9% NaCl solution. The first group (control - GC) was restricted to such procedure. In the wounds of the second (GM), third (GO) and fourth groups (GF), after cleaning, we respectively applied 1ml of honey, 1ml of copaíba oil-resin and 1ml of cream containing fibrinolysin, deoxyribonuclease and chloramphenicol. The wounds were occluded with sterile gauze. Immediately after the incision and on days three, seven and 14 of the experiment, the wounds were copied and contraction was analyzed using planimetry. After euthanasia, we histologically evaluated the inflammatory reaction and collagen in the scars. Results: the reduction of the wound area of GM (p=0.003), GO (p=0.011) and GF (p=0.002) were higher than the GC. The amount of type-I collagen present in GM and GO was higher than in GC and GF groups (p<0.05). There was a predominance of chronic inflammatory stage in GM (p=0.004), GO (p<0.001) and GF (p=0.003) when compared with GC. Conclusion: the topical use of honey and copaíba oil-resin increases wound contraction, the presence of type-I collagen and accelerates healing.

[Right treatment of red eyes - prescription of topical antibiotics for infectious conjunctivitis is still common in Sweden]. / Rekommendationer följs inte vid okomplicerad konjunktivit - Tillståndet behandlas ofta med topikala antibiotika i strid mot aktuell kunskap.

Conjunctivitis is one of the most common ophthalmologic conditions in general medical practice. In most cases, it is self-limiting and do not require topical antibiotic therapy. In a retrospective, observational cohort study during 2013-2017 in a region in Sweden conjunctivitis was diagnosed in 32 000 cases in primary care. Antibiotics were prescribed in 66% of undefined and in 83% of purulent conjunctivitis. Fusidic acid was the most common medication with 81% followed by chloramphenicol with 17%. Although unnecessary, the treatment is probably harmless. Toxicity is uncommon and the cost is low. Increased consciousness of this issue may however decrease resistance to antibiotics and support evidence-based medical practice.