Doxycycline HCl Research Articles

Microencapsulated Benzoyl Peroxide for Rosacea in Context: A Review of the Current Treatment Landscape.

Rosacea, a chronic skin condition affecting millions of people in the USA, leads to significant social and professional stigmatization. Effective management strategies are crucial to alleviate symptoms and improve patients' quality of life. Encapsulated benzoyl peroxide 5% (E-BPO 5%) is a newly FDA-approved topical treatment for rosacea that shows promise in enhancing therapeutic response and minimizing skin irritation. This review aims to assess the role of recently FDA approved E-BPO 5% in the current treatment landscape for rosacea management, as it is not yet included in clinical guidelines that predominantly rely on older approved therapies. The review focuses on randomized controlled trials conducted in English-speaking adults. It evaluates the efficacy, safety, and tolerability of various US Food and Drug Administration (FDA)-approved agents used for rosacea treatment, including E-BPO cream, metronidazole gel, azelaic acid gel and foam, ivermectin cream, minocycline foam, oral doxycycline, brimonidine gel, and oxymetazoline HCl cream. Existing therapies have been effective in reducing papulopustular lesions and erythema associated with rosacea for many years. E-BPO 5% offers a promising addition to the treatment options due to its microencapsulation technology, which prolongs drug delivery time and aims to improve therapeutic response while minimizing skin irritation. Further research is necessary to determine the exact role of E-BPO 5% in the therapeutic landscape for rosacea. However, based on available evidence, E-BPO 5% shows potential as a valuable treatment option for managing inflammatory lesions of rosacea, and it may offer benefits to patients including: rapid onset of action, demonstrated efficacy by Week 2, excellent tolerability, and sustained long-term results for up to 52 weeks of treatment.

Modified ESR-based photosafety test (ESR-PT) detecting singlet oxygen and free radical formation.

The electron spin resonance-based photosafety test (ESR-PT) was modified using a new parameter, photoreactivity index (PRI), to detect singlet oxygen and free radical photoproducts simultaneously. With this modification, the modified ESR-PT is expected to reduce the number of false negative results due to chemicals producing free radical photoproducts other than singlet oxygen. The assay performance of the modified ESR-PT was evaluated using 56 chemicals, including hydrophobic chemicals. When using the PRI cutoff value of 2.0 in the modified ESR-PT, the accuracy relative to photosafety reference data was 91.1%, and the applicability (100%) was better than the other non-animal photosafety test. Among the chemicals producing positive results, bithionol, fenticlor, and doxycycline HCl were considered positive based on the detection of free radical photoproducts, suggesting that these three chemicals may have phototoxic or photoallergic potential via radical reactions. Additionally, this finding demonstrated the fundamental advantage of the modified ESR-PT using ESR spectroscopy, which can detect radicals selectively and quantitatively. Accordingly, the new parameter PRI is effective for photosafety evaluations based on not only singlet oxygen but also free radical photoproducts generated from chemicals. Therefore, the modified ESR-PT has a great potential for a photosafety test method applicable to various chemicals.

BACTERIOLOGICAL AND MOLECULAR STUDIES ON E. COLI ISOLATED FROM BROILER CHICKENS

Avian colibacillosis is one of the most important diseases of chickens, resulting in high economic losses as well as high morbidity and mortality. In the current study, the prevalence of avian colibacillosis was studied in 200 broiler chickens obtained from different farms in Beni-Suef and El-Fayoum Governorates. A total of 200 pooling samples were collected aseptically from heart blood as well as the affected internal organs including airsacs, pericardial sac, liver, lung and ascetic fluids of slaughtered diseased and freshly dead broiler chickens. Bacteriological examination of the collected samples showed that a total of 58 E. coli isolates were recovered with a prevalence of 29%. The results of in-vitro antimicrobial susceptibility tests revealed that E. coli isolates showed high sensitivity to colistin sulphate only (72.4%). On the other hand, high resistances were recorded to all other antimicrobials including cefotaxime sodium and florophenicol (96.6% for each), apramycin, ciprofloxacin and gentamicin (91.4% for each), enrofloxacin and lincomycin (91.4% for each), streptomycin (89.7%), sulphamethoxazol-trimethoprim and doxycycline HCl (77.6% for each) and spiramycin (75.9%). Moreover, all E. coli isolates were MDR (100%). PCR was applied on 10 E. coli MDR isolates for detection of 7 genes; 4 resistance-associated genes (blaTEM, tetA, sul1 and dfrA) as well as 3 virulence-associated genes (tsh, iss, iutA). The results revealed that 90% of isolates had at least 4 virulence genes while only10% had not any gene. The gene blaTEM was the most prevalent (90%) followed by iutA and sul1 (70% for each) then, iss and tetA (60% for each). Meanwhile dfrA and tsh genes were represent in 40% and 30% of isolates, respectively.

Z‐scheme 3 D g‐C3N4/TiO2−x Heterojunctions with High Photocatalytic Efficiency

AbstractThe 3D network structure composed of g‐C3N4 nanorods was prepared via treatment of bulk g‐C3N4 with hot HNO3 followed by adjustment the pH and lyophilization. Then the 3D g‐C3N4/TiO2−x heterojunctions with a strong interface was constructed via loading TiO2−x nanoparticles onto the 3D g‐C3N4 networks under hydrothermal conditions. The structure and morphology of the 3D g‐C3N4/TiO2−x heterojunctions was characterized by infrared spectrum (FTIR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and field emission transmission electron microscope (TEM). The photo‐degradation rate of Doxycycline HCl for 3D g‐C3N4/TiO2−x heterojunction is about 4 times of that original bulk‐C3N4 and 2.75 times of 3D g‐C3N4. The improved photocatalytic efficiency is attributed to 3D g‐C3N4 networks, which provides the more transfer channel to accelerate the electron transportation and the strong heterointerface between g‐C3N4 and TiO2−x which promotes the separation of the electron‐holes. Besides, more adsorption capacity of the pollutant onto the 3D g‐C3N4/TiO2−x also contributed to this high efficiency.

Molecular characterization of Antimicrobial-Resistant Escherichia coli isolated from broiler chickens

Avian colibacillosis is one of the most important diseases of chickens resulting in significant economic losses as well as high morbidity and mortality. In the current study, the prevalence of avian colibacillosis was studied in different farms of broiler chickens in Beni-Suef, EL-Minia, ElFayoum, Assiut and Sohag Governorates. A total of 300 pooling samples were collected aseptically from heart blood as well as the affected organs including air sacs, pericardial sac, and liver of slaughtered diseased and freshly dead broiler chickens. Bacteriological examination of the collected samples showed that a total number of 80 E. coli isolates were recovered with an overall prevalence of 26.7. The highest prevalence was recorded in El-Fayoum (33.3%) followed by El-Minia (25%), Beni-Suef and Assiut (22.5% for each) while the lowest prevalence was in Sohag (17.5%). The invitro antimicrobial susceptibility testing revealed that E. coli isolates showed high sensitivity to colistin sulphate only (70%). Meanwhile, high resistances were recorded against other antimicrobials including amoxicillin (97.5%), cefotaxime sodium and florfenicol (95% for each), apramycin, ciprofloxacin and gentamicin (92.5% for each), streptomycin (90%), enrofloxacin (87.5%), trimethoprim-sulphamethoxazol and doxycycline HCl (77.5% for each). All E. coli isolates were MDR (100%). PCR was applied on 10 MDR E. coli isolates to detect the 3 resistance-associated genes (qnrA, tetA and aac(6′)- Ib-cr and 5 virulence-associated genes (iutA, hly, sta, lt and astA). The results showed that all the tested isolates (100%) harbored qnrA, tetA, iutA and astA genes meanwhile aac(6′)-Ib-cr, hly, sta and lt genes were not detected in any isolate.

Multifunctional periodontal membrane for treatment and regeneration purposes

Periodontitis is a chronic inflammatory disease that causes gum tissue degeneration and alveolar bone and tooth loss. The aim of this study is to develop a multifunctional matrix for the treatment of periodontitis and enhancement of regeneration of the periodontal tissue. The matrix was prepared from vitamin E containing hydrogel made of alginate and gelatin, and doxycycline HCl containing methoxy poly(ethylene glycol)-block-polycaprolactone micelles. Methoxy poly(ethylene glycol)-block-polycaprolactone was synthesized with ring-opening polymerization technique and characterized by proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy, differential scanning calorimetry, and gel permeation chromatography. Micelles were characterized by measuring zeta potential, hydrodynamic diameter, drug encapsulation efficiency, drug loading capacity, and in vitro drug-release kinetics. Micelles were obtained with an average size of 164 nm and drug loading amount of 5.8%. The activity of doxycycline HCl–loaded micelles and vitamin E containing hydrogels was determined against Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus) with disk diffusion method. Bio-efficacy of micelle-loaded alginate–gelatin hydrogels were tested in vitro using L929 fibroblasts and dental pulp stem cells. Doxycycline HCl–loaded micelles and vitamin E containing hydrogels showed a sustained release and exhibited inhibition zone against E. coli and S. aureus. Hydrogels with vitamin E and doxycycline HCl–loaded micelles promoted osteogenic differentiation of dental pulp stem cells. Results suggest that alginate–gelatin hydrogels containing doxycycline HCl–loaded micelles and vitamin E can be good candidates for the treatment of periodontitis and tissue regeneration.

Impact of Different Root Conditioning Agents on Periodontally Affected Root Surface: A Scanning Electron Microscope Study

The present study aimed to evaluate the effect of various root-conditioning agents on root surfaces that are periodontally affected. A total of 90 human teeth having single root that were extracted because of chronic periodontitis were chosen. The extracted teeth were cleaned of saliva and blood using a soft-bristled brush and distilled water. The investigational groups were categorized into group I-doxycycline HCl, group II-ethylenediaminetetraacetic acid, and group III-tetracycline HCl. Samples were readied for histological study by scanning electron microscope (SEM). The SEM was used to assess the effectiveness of smear layer removal, amount of patent dentinal tubules out of the totality of dentinal tubules present, and the appreciation of collagen fiber-like structures inside the intertubular area. The highest efficacy for smear layer removal was seen for group III-tetracycline HCl samples (1.80 ± 0.148) followed next by group II-EDTA (1.36 ± 0.230), and group I-doxycycline HCl (1.30 ± 0.283). The highest number of patent dentinal tubules were seen in group III-tetracycline HCl (44.50 ± 0.18) followed immediately by group II-EDTA (38.10 ± 0.42), and group I-doxycycline HCl (34.90 ± 0.23). The highest number of appreciation of collagen-like structures was recorded in group III-tetracycline HCl (2.64 ± 0.04) followed next by group I-doxycycline HCl (1.88 ± 0.10) and group II-EDTA (1.76 ± 0.28). The present in vitro study concludes tetracycline HCl root-conditioning agent to be significantly more efficient in smear layer removal, exposing collagen fibers and amount of patent dentinal tubules than doxycycline HCl and EDTA. The modification of the root surface of human teeth with the use of root conditioning agents leads to enhanced attachment by connective tissue resulting in improved reconstructive periodontal treatment goals.

Comparative Study of Antifungal Efficacy of Various Endodontic Irrigants with and without Clotrimazole in Extracted Teeth Inoculated with Candida albicans

To assess the application of clotrimazole (1%) as a complementary antifungal agent along with sodium hypochlorite (5.25%), chlorhexidine gluconate (2%), and doxycycline hydrochloride (5%) against Candida albicans. Seventy freshly extracted single-rooted premolars with matured apices were collected, stored, and handled according to the Occupational Safety and Health Administration (OSHA) and the Center for Disease Control and Prevention (CDC) guidelines and recommendations. These were divided into three groups (two tests and one control group) depending on irrigants used. The efficacy of each irrigant group was compared. The observations were statistically analyzed by the multiple intergroup comparisons using ANOVA and Scheffe multiple comparisons (p < 0.001). The sodium hypochlorite (group IA-mean 129.6) has shown a statistically significant decrease in colony-forming units (CFUs) (p < 0.01) on comparison with chlorhexidine [(IB) mean 190.2]. A similar result was obtained in comparison with the sodium hypochlorite group (IA) and doxycycline HCl group [(IC) mean 318.4] and also between the sodium hypochlorite group (IA) and the control group [(III) mean 554.2]. The intragroup comparison of group II, group IIA (mean 63.3), and group IIB (mean 73.8) showed no statistically significant difference. Group III (mean 554.2) was the least effective of all the subgroups. Sodium hypochlorite showed better antifungal efficacy than chlorhexidine and doxycycline when used alone. The addition of clotrimazole increased the efficiency of doxycycline also, but it was less compared to sodium hypochlorite and chlorhexidine. Within the limitations of this study, the inclusion of 1% clotrimazole increased the antifungal efficacy of all the three irrigants. Our study compared the efficacy of the various endodontic irrigants and also determined their efficiency with the addition of the antifungal agent. Clotrimazole (1%) addition in irrigating solutions showed better results and promoted faster healing.

DFD-29, a low dose oral minocycline, demonstrates superior efficacy as compared to placebo and Oraycea ® Capsules (doxycycline HCl) in subjects with papulopustular rosacea

Abstract not available.

Higher bioavailability of doxycycline in broiler chickens with a novel in-feed pharmaceutical formulation

Bioavailability of a new, long-acting (LA) pharmaceutical preparation for administering doxycycline as in-feed medication to broiler chickens was compared to the standard in-feed administration of doxycycline. A commercial poultry house harboring Ross-308 broiler chickens, weighing 450 g, was divided into 7 sections as follows: doxy-FOLA group (n = 6,000 chickens divided into 3 replicates) medicated with 10% doxycyline, long-acting pellets at a dose of 400 g of doxycycline HCl/ton of food, resulting in a calculated dose of 48 mg/kg for 5 d; doxy-ref group (n = 6,000, divided into 3 replicates) medicated as for doxy-FOLA, but using a 20% commercial preparation of doxycycline. A third group of 300 broiler chickens (divided into 3 replicates), received a single IV dose of 48 mg/kg from a 2.4% solution of doxycycline HCl under ketamine anesthesia. Blood samples were obtained at designated times, serum was harvested, and doxycycline concentrations determined by high-performance liquid chromatography (HPLC). Bioavailability values were 156% and 227% on d 1 and 5 for doxy-FOLA and 13% and 23% for doxy-ref, on the same days. Mean residence time (MRT) and elimination half-life (T½β) were statistically different (P < 0.05) in doxy-FOLA group as compared to doxy-ref group (MRT: 26 h and 5.2 h; and T½β: 18 h vs 3 h, on the first day for doxy-FOLA and doxy-ref, respectively). Based on 3 levels of bacterial sensitivity of E. coli derived from a small survey carried out (i.e., 1.0, 2.0, and 4.0 μg/mL) and considering pharmacokinetic/pharmacodynamic (PK/PD) ratios required for this time-dependent antibacterial drug, it is possible to postulate that doxy-FOLA outstrips the reference preparation maintaining higher and more prolonged serum concentrations of doxycycline and consequently complying better with PK/PD ratios regarded as optimal for this drug. The advantages of using doxy-FOLA in poultry medicine include a more comprehensive use of the active principle, which in turn should have a better impact on bacterial diseases. Yet, a longer withdrawal time is anticipated based on an almost 4-fold increment in the MRT value.

Prevalence of multiple drug resistant Streptococcus suis in and around Guwahati, India.

Aim:This study was conducted to determine the prevalence and antimicrobial susceptibility of Streptococcus suis and their resistance patterns isolated from both clinically healthy carriers and diseased pigs in and around Guwahati, Assam, India.Materials and Methods:A total of 497 samples were collected during October, 2012, to April, 2014, from clinically healthy (n=67) and diseased (n=230) pigs of varying age and either sex maintained under organized and unorganized farming systems. Samples were processed for isolation and identification of S. suis by biochemical characterization and polymerase chain reaction targeting the housekeeping gene glutamate dehydrogenase. In vitro antimicrobial susceptibility of the recovered isolates against nine antibiotic groups comprising 17 antimicrobial agents was studied by standard method.Results:Of the 497 samples examined, 7 (1.41%) isolates were confirmed to be S. suis of which 5 (1.87%) and 2 (0.87%) were derived from clinically healthy and diseased pigs, respectively. All the isolates were susceptible to gentamicin, amikacin, and erythromycin (100%) followed by the penicillin group and enrofloxacin (85.71%), ceftriaxone, doxycycline HCL, ofloxacin and chloramphenicol (71.43%), to kanamycin, clindamycin and co-trimoxazole (42.85%). The isolates showed least susceptibility to cefalexin, tetracycline and streptomycin (28.57%). All the five S. suis isolates from clinically healthy pigs were susceptible to penicillin G, amoxyclav, doxycycline HCl, gentamicin, amikacin and erythromycin, 80.00% isolates susceptible to ampicillin, enrofloxacin and ofloxacin, 60.00% to ceftriaxone, kanamycin and chloramphenicol, 40% to cefalexin, tetracycline, clindamycin and co-trimoxazole, respectively. Only 20.00% isolates were susceptible to streptomycin. Both the isolates recovered from diseased pigs were susceptible to ampicillin, ceftriaxone, gentamicin, amikacin, enrofloxacin, erythromycin, and clindamycin. On the other hand, both the isolates were resistant to cefalexin, tetracycline, doxycycline HCL, and kanamycin. Altogether five different resistance patterns (multi-drug resistance) were observed. Of the seven S. suis isolates, two isolates were susceptible to all the 17 antimicrobial agents, one isolate was resistant to four antimicrobial agents, two isolates to seven agents, one isolate to nine agents, and one isolate exhibited resistance to 14 antimicrobial agents.Conclusion:This study was conducted to determine the prevalence of S. suis in clinically healthy and diseased pigs and their antimicrobial susceptibility patterns. All the isolates were susceptible to gentamicin, amikacin and erythromycin, and most of them were resistant to cefalexin, tetracycline and streptomycin. Five different patterns of antimicrobial resistance (multi-drug resistance) were observed.

Radio Frequency-Activated Nanoliposomes for Controlled Combination Drug Delivery.

This work was conducted in order to design, characterize, and evaluate stable liposomes containing the hydrophobic drug raloxifene HCl (RAL) and hydrophilic doxycycline HCl (DOX), two potentially synergistic agents for treating osteoporosis and other bone lesions, in conjunction with a radio frequency-induced, hydrophobic magnetic nanoparticle-dependent triggering mechanism for drug release. Both drugs were successfully incorporated into liposomes by lipid film hydration, although combination drug loading compromised liposome stability. Liposome stability was improved by reducing the drug load and by including Pluronics® (PL) in the formulations. DOX did not appear to interact with the phospholipid membranes comprising the liposomes, and its release was maximized in the presence of radio frequency (RF) heating. In contrast, differential scanning calorimetry (DSC) and phosphorus-31 nuclear magnetic resonance ((31)P-NMR) analysis revealed that RAL developed strong interactions with the phospholipid membranes, most notably with lipid phosphate head groups, resulting in significant changes in membrane thermodynamics. Likewise, RAL release from liposomes was minimal, even in the presence of RF heating. These studies may offer useful insights into the design and optimization of multidrug containing liposomes. The effects of RAL on liposome characteristics and drug release performance underscore the importance of appropriate physical-chemical analysis in order to identify and characterize drug-lipid interactions that may profoundly affect liposome properties and performance early in the formulation development process.

A quality by design approach to optimization of emulsions for electrospinning using factorial and D-optimal designs

Emulsion electrospinning is a multifactorial process used to generate nanofibers loaded with hydrophilic drugs or macromolecules for diverse biomedical applications. Emulsion electrospinnability is greatly impacted by the emulsion pharmaceutical attributes. The aim of this study was to apply a quality by design (QbD) approach based on design of experiments as a risk-based proactive approach to achieve predictable critical quality attributes (CQAs) in w/o emulsions for electrospinning. Polycaprolactone (PCL)-thickened w/o emulsions containing doxycycline HCl were formulated using a Span 60/sodium lauryl sulfate (SLS) emulsifier blend. The identified emulsion CQAs (stability, viscosity and conductivity) were linked with electrospinnability using a 33 factorial design to optimize emulsion composition for phase stability and a D-optimal design to optimize stable emulsions for viscosity and conductivity after shifting the design space. The three independent variables, emulsifier blend composition, organic:aqueous phase ratio and polymer concentration, had a significant effect (p<0.05) on emulsion CQAs, the emulsifier blend composition exerting prominent main and interaction effects. Scanning electron microscopy (SEM) of emulsion-electrospun NFs and desirability functions allowed modeling of emulsion CQAs to predict electrospinnable formulations. A QbD approach successfully built quality in electrospinnable emulsions, allowing development of hydrophilic drug-loaded nanofibers with desired morphological characteristics.

Effect of doxycycline on the apical seal of the retrograde filling materials : An ex - vivo study

Objectives: To evaluate the efficiency of Doxycycline Hydrochloride on the apical seal of retrograde filling materials. Materials and methods: Sixty freshly extracted human maxillary central incisors were selected. Endodontic access cavity preparation was done and the canals were located. Cleaning and shaping of root canals was done using k-files upto size 45. The root canals were obturated with gutta percha in lateral condensation technique. The apical 2 mm were resected, and a retrograde preparation was made to a depth of 3mm with a no:331 bur. The teeth were divided into 6 groups of 10 teeth each. The apical cavities in Group A, B and C were irrigated with saline as control groups. The cavities in Group D, E and F were irrigated with doxycycline HCl, 100 mg/ml as experimental group. The apical cavities in Group A and D were filled with IRM, Group B and E were filled Type-II GIC, Group C and F were filled with MTA. The surfaces of all the teeth except the apical 3mm were sealed using two coats of nail polish and one coat of sticky wax. All the teeth were then immersed in India ink dye and were subjected to thermocycling for 7 days. The teeth were then longitudinally sectioned and the degree of linear dye penetration was measured using stereomicroscope The mean results were statistically evaluated by Student-Newman-Keuls test and ANOVA. Results : MTA and GIC retrograde filling materials allowed significantly less dye leakage than IRM in both experimental and control groups, especially when preceded with doxycycline irrigation of the apical cavities. Conclusion: Irrigation of the apical cavities with Doxycycline Hydrochloride significantly improved the apical seal of retrograde filling materials. Abbreviations: MTA-Mineral Trioxide Aggregate. GIC-Glass ionomer cement. IRM-Intermediate restorative material.

Effect of Natural Spices on Plasma Proteins in Broiler Chicks

This study was designed to compare four different medicinal plants, cinnamon (Cinnamomum verum), cumin (Cuminum cyminum), fenugreek (Trigonella foenum-graecum) and ginger (Zingiber officinale), as natural feed additives with the Doxystin: “Doxycycline HCl 50 mg and Colistin sulfate” (known antimicrobial growth promoter) on plasma biochemical values of broiler chicks includes total protein, albumin, globulin, albumin/ globulin (A/G) ratio and the Alkaline phosphatase activity. Two hundred and forty, (one day-old) broiler chicks were randomly assigned to six groups of similar mean weight each included four replicates of ten chicks. The control group received broilers basal diet. For the treated groups, the basal diet was supplemented with one of the following: the antimicrobial (Doxystin) as 0.5% or one of the spices C. verum, C. cyminum, T. foenum-graecum and Z. officinale as 2%. The results showed significant (P<0.05) increase in the serum total protein and the globulins concentrations in T.foenum-graecum group compared to the control group and other spice treated groups, also the globulins levels were significantly (P<0.05) higher in Doxystin and C. cyminum groups compared to the control group. The serum albumin/globulin ratio was significantly (P<0.05) decreased in all experimental groups compared to the control group. Treatment with different spices in the present work increased the total proteins and the serum globulins fraction of the blood proteins, albumin remains unchanged and this effect lowered A/G ratio. These findings suggest improved rate of growth and immunity in the broiler chicks. The results also showed no significant difference between the experimental groups and the control group for the serum alkaline phosphatase (ALP) activity. This suggested that no significant liver problem will arise from the use of the spices as treatments

Formulation and release of doxycycline HCL from an ion activated in situ gelling delivery system for the treatment of periodontal disease

AbstractThis study reports on the formulation of doxycycline HCL in an ion activated in situ gelling delivery system and its implications for the treatment of periodontal disease. The system is based on the use of alginate as the gelling agent and hydroxypropyl methylcellulose (HPMC) as a viscosity enhancing agent. The ion activated gelling mechanism in this system is based on the concept of interaction with the divalent calcium ions present in the gingival crevicular fluid (GCF). The gelling capacity of the prepared formulations was assessed visually and by investigating their rheological behavior upon mixing with human blood serum since it has the same composition as the GCF. The rheological behavior of all formulations was not affected by incorporation of the drug. In vitro release studies showed that the alginate/HPMC mixture, upon gelling after mixing with serum, can sustain the release of doxycycline HCL for an extended period of time which was more than 12 days. These results indicated that this system can be used as an in situ gelling local delivery system for the treatment of periodontal disease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

A thermo-sensitive release system based on polymeric membrane for transdermal delivery of doxycycline HCl

A class of intelligent thermo-sensitive membranes was synthesized by immobilizing the thermo-sensitive polymeric gel, poly( N-isopropylacrylamide) (PNIPAAM) or PNIPAAM- co-2 mol% acrylic acid (AA) on the surface and inside the pores of a hydrophilized polyvinylidene fluoride (PVDF) membrane, hereafter referred to as PNIPAAM-PVDF membrane or 2%AA-PVDF membrane, respectively. Such gel-modified membranes have drastically different permeation properties upon the volume-phase transition of the immobilized gel at its lower critical solution temperature (LCST). The permeability and flux of 2%AA-PVDF membrane at its LCST (33 °C) almost doubled compared to those at 32 °C for the agent doxycycline HCl partitioning from its solution/dispersion in light mineral oil in the donor reservoir bounded by the membrane. Further in vitro studies with a mouse skin mounted beneath the 2%AA-PVDF membrane demonstrated that its release can be switched on and off at the LCST of the gel. At 32 °C, there was no doxycycline HCl release through skin for 24 h, while at 33 °C, the ailing condition, 30 μg/cm 2 of doxycycline HCl was accumulated in the receptor through the skin after 24 h with the permeability and flux being very close to those from a regular PVDF/mouse skin composite. Since human skin temperature changes from 32 °C to 33 °C under certain feverish conditions, the gel-modified membranes can be exploited as a transdermal controlled-release system for treating fever symptoms. However, for smaller molecules such as caffeine, different configurations yielded almost the same permeation profiles.

Inflammatory response to chlorhexidine, minocycline HCl and doxycycline HCl in an in vivo mouse model

To examine the effect of locally delivered antimicrobial drugs on the inflammatory response in an in vivo mouse chamber model. Two weeks following chamber implantation, 24 BALB/c mice, in the experimental group, were given an intra-chamber challenge of heat-killed Porphyromonas gingivalis, followed immediately by injection of the specific antimicrobial drug: 2000 microg/ml chlorhexidine (CHX); 1500 microg/ml minocycline HCl;and 1500 microg/ml doxycycline HCl (concentrations achieved in the periodontal pocket with commercial controlled-release delivery systems). A second group of 24 animals received only the antimicrobial treatment without P. gingivalis challenge. Intra-chamber exudates were sampled at 2 and 24 h following the challenge, and leucocytes, TNFalpha, IFNgamma and IL-10 were evaluated. At 2 h, minocycline HCl induced high levels of IL-10, TNFalpha and IFNgamma, while CHX reduced the levels of TNFalpha and IFNgamma. By 24 h, these responses were attenuated. Following bacterial challenge, the antibacterial agents attenuated the inflammatory process, each in its own fashion. Antibacterial agents applied locally have the ability to induce an inflammatory response. They also modify the inflammatory response to P. gingivalis independent of their antimicrobial effect. CHX and doxycycline HCl appear to have the most marked anti-inflammatory effect.

Iontophoretic transdermal drug delivery system using a conducting polymeric membrane

This work investigated the application of a porous polyaniline (PANi) membrane as a conducting polymeric membrane as well as an electrode in an iontophoretic transdermal drug delivery (TDD) system. Model drugs studied were: caffeine (MW: 194.2), lidocaine HCl (MW: 270.8) and doxycycline HCl (MW: 480.1). The PANi membrane was first tested as a simple membrane between the donor and receptor solutions; it provided satisfactory permeation profiles; the observed flux values were well described by a simplified mass transport model. A mouse skin was then mounted beneath the PANi film; such a composite system also presented satisfactory permeation profiles. Iontophoretic TDD experiments were next performed using both Ag|AgCl electrodes and PANi|AgCl electrodes for comparison; a PANi anode replaced the Ag anode in the last set. For doxycycline HCl, the flux and the 24-h accumulation from the PANi|AgCl set were 94.4 ± 81.2 μg/cm 2 h and 2760 ± 3980 μg/cm 2, respectively; those from the Ag|AgCl set were zero. For lidocaine HCl, the flux and 10-h accumulation from the PANi|AgCl set were, respectively, 43 ± 15 μg/cm 2 h and 392 ± 130 μg/cm 2; the corresponding values from the Ag|AgCl set were 48 ± 20 μg/cm 2 h and 348 ± 78 μg/cm 2. Porous polyaniline membrane appears to be capable of replacing the Ag part of Ag|AgCl electrode system; further such a membrane can exercise additional control over agent transport rate. Aqueous-organic partitioning system through the porous membrane of PANi was tested with this novel technique as well. Because of the rather low porosity of the synthesized PANi film, such a system did not yield a high permeation rate.

Evaluation of the antibacterial substantivity of several intra‐canal agents

The aim of this in vitro study was to compare the antimicrobial substantivity of 2% chlorhexidine gluconate (CHX), 100 mg ml(-1) doxycycline and 2.6% sodium hypochlorite (NaOCl) in bovine root dentine. Eighty dentine tubes prepared from bovine incisors were infected in vitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups as follows: doxycycline HCl; CHX; NaOCl; infected dentine tubes (positive control); and sterile dentine tubes (negative control). Dentine chips were collected with round burs into tryptic soy broth. After culturing, the number of colony-forming units (CFU) was counted. In all experimental groups, the number of CFU was minimum in the first cultures, and the results obtained were significantly different from each other at any time period (P < 0.05). In the first culture, the NaOCl group and doxycycline HCl group showed the lowest and highest number of CFU, respectively. In each group, the number of CFU increased significantly by time-lapse (P < 0.05). In conclusion, the substantivity of CHX was significantly greater than NaOCl and doxycycline.