ABSTRACT
Objective To make finite element analysis and compressive performance test on three-dimensional (3D) printed personalized poly-ether-ether-ketone (PEEK) condyle prosthesis, so as to analyze stress distribution characteristics and mechanical properties of the prosthesis, and to evaluate its clinical value and prospect. Methods The finite element models of PEEK condyle prosthesis, mandible and fixation screw were established by software such as CBCT, Mimics, Geomagic Studio, SolidWorks and ANSYS Workbench. The maximum mastication force was applied, and the maximum stress of the condyle prosthesis and screw, as well as the stress and strain of the mandible were recorded. In order to simulate the actual clinical situation, a special fixture was designed to test compression performance of the condyle prosthesis prepared by the fused deposition modeling (FDM) and selective laser sintering (SLS) at the rate of 1 mm/min. Results The peak stress of the PEEK condyle prosthesis was 10.733 MPa, which was located at the back of the condyle neck. The peak stress of 5 fixing screws was 9.707 5 MPa, which appeared on the 2# and 5# screws near the trailing edge of the mandibular ascending branch. The peak stress of both the prosthesis and the screw was smaller than its yield strength. The maximum pressure of the condyle prosthesis prepared by FDM and SLS was (3 814.7±442.6) N and (1 193.970±260.350) N, respectively. Compared with the SLS preparation, the FDM prepared prosthesis not only had higher compression strength but also better toughness. Conclusions The 3D printed personalized PEEK condyle prosthesis shows uniform stress distributions and good mechanical properties, which can provide the theoretical basis for PEEK as reconstruction material for repairing temporomandibular joint.
ABSTRACT
The present investigation was undertaken with an objective of formulating mouth dissolving films (MDFs) of an anti-migraine drug, Sumatriptan Succinate (SUM) to enhance convenience and compliance to the elderly and pediatric patients for better therapeutic efficacy. Film former, Hydroxy Propyl Methyl Cellulose along with film modifier/solubilizing agents, Polyvinyl pyrrolidone K30 (PVP K30) and Sodium Lauryl Sulphate (SLS) were used to formulate MDFs. The MDFs were prepared by wet film applicator technique and were evaluated for in vitro dissolution characteristics, in vitro disintegration time, and their physico-mechanical properties. MDFs with 13% (w/w) of HPMC E5 gave better dissolution properties when compared to HPMC E15. MDFs with PVP K30 and SLS gave superior dissolution properties when compared to MDFs without PVP K30 and SLS. The dissolution properties of MDFs with PVP K30 were superior when compared to MDFs with SLS. Overall, SUM MDFs showed good mechanical properties like tensile strength, folding endurance and % elongation and dissolution properties. These results suggest that the HPMC is an excellent film former which gives rapid drug release.
ABSTRACT
The aim of this work was to study the formulation and in vitro characterization of hydro dynamically balanced floating matrix tablets using Cefuroxime axetil (CA) as model drug. Different excipients such as hydroxy propyl methyl cellulose (HPMC) K15M, E5LV (gelling agent), sodium bicarbonate (gas generating agent) and sodium lauryl sulfate (SLS) (solubility enhancer) were used in order to optimize the drug release profile as well as floating property. Decrease in release characteristics with high viscous polymer were observed due to increased gel strength, tortuosity and length of drug diffusion path. Significant difference (p<0.5) in release rate was found at different concentration of SLS. The release mechanisms were explored and explained with zero order, first order, Higuchi, Korsmeyer and Hixson-Crowell equations. The release rate, extent and mechanism were governed by the content of polymer. The polymer content and amount of floating agent significantly affected the time required for 50%of drug release (t50%), mean dissolution time (MDT), release rate constant, and diffusion exponent (n).Kinetic modeling of dissolution profile revealed that the drug release mechanism could range from diffusion controlled to case II transport, which was co-dominated by diffusion polymer erosion in the release mechanism.
ABSTRACT
A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate.The experimental results suggest that the phcniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response.Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987.The limit of detection is 58.31 μg/m L.The modified electrode shows good sensitivity and repeatability.
ABSTRACT
Efavirenz, a widely prescribed anti retroviral drug belongs to class IΙ under BCS and exhibit low and variable oral bioavailability due to its poor aqueous solubility. Its oral absorption is dissolution rate limited and it requires enhancement in the solubility and dissolution rate for increasing its oral bioavailability. The objective of the study is to evaluate the feasibility of formulating efavirenz –βCD– PVP K30/SLS inclusion complexes into tablets and to evaluate the effects of βCD, PVP K30and SLS on the dissolution rate and dissolution efficiency of efavirenz tablets in a 23 factorial study. A comparative evaluation of wet granulation and direct compression methods was made for the preparation of tablets employing drug – βCD – PVP K30/ SLS inclusion complexes. Drug – βCD- PVP K30/ SLS inclusion complexes were prepared by kneading method. Tablets each containing 50 mg of efavirenz were prepared by wet granulation and direct compression methods employing various βCD complexes as per 23 factorial design and the tablets were evaluated for dissolution rate and other physical properties. Efavirenz tablets formulated employing dug – βCD – PVP K30/ SLS inclusion complexes and prepared by direct compression method disintegrated rapidly when compared to those made by wet granulation method. Efavirenz dissolution was rapid and higher from the tablets formulated employing drug- βCD- PVP K30 /or SLS inclusion complexes when compared to the tablets containing efavirenz alone in both wet granulation and direct compression methods. The individual as well as combined effects of the three factors involved i.e., βCD ( factor A), PVP K30( factor B) and SLS( factor C) were highly significant (P< 0.01) in enhancing the dissolution rate (K1) and dissolution efficiency (DE 30) of efavirenz in both wet granulation and direct compression methods. Among the three factors βCD (factor A) gave highest enhancement in the dissolution rate (K1) and dissolution efficiency (DE 30) of efavirenz tablets in both wet granulation and direct compression methods. SLS (factor C) alone gave low dissolution rate in both wet granulation and direct compression methods .Overall direct compression method gave higher dissolution rates (K1) and dissolution efficiency (DE 30) values than the wet granulation method in all the cases. Combination of βCD with either PVP K30 or SLS or both gave a significantly higher dissolution rate (K1) of efavirenz in both wet granulation and direct compression methods. Hence a combination of βCD with either PVP K30 or SLS or both is recommended to enhance the dissolution rate and efficiency of efavirenz tablets.
ABSTRACT
The objective of the study is to evaluate the individual main effects and combined (or interaction) effects of Hydroxy propyl β cyclodextrin (HPβCD), poly vinyl pyrrolidone (PVP K30) and sodium lauryl sulphate (SLS) on the solubility and dissolution rate of efavirenz in a series of 23 factorial experiments. The solubility of efavirenz in eight selected fluids containing HPβCD, PVP K30 and SLS as per 23 factorial study was determined. The solubility of efavirenz was markedly enhanced by HPβCD (2.95 fold), PVP K30 (2.49 fold) and SLS (226.96 fold) individually. Combination of HPβCD with PVP K30 and SLS gave a markedly higher enhancement in the solubility of efavirenz than is possible with them individually. HPβCD in combination with PVP K30 and SLS gave respectively 4.05 and 387.63 fold increase in the solubility of efavirenz. Solid inclusion complexes of efavirenz - HPβCD were prepared with and without PVP K30 and SLS as per 23- factorial design by kneading method and were evaluated. ANOVA indicated that the individual main effects of HPβCD, PVP K30 and SLS and their combined effects in enhancing the solubility and dissolution rate (K1 )and dissolution efficiency (DE30 ) were highly significant (P < 0.01).HPβCD alone gave a 16.74 fold increase in the dissolution rate of efavirenz. HPβCD in combination with PVP K30 and SLS gave respectively 19.98 and 25.13 fold increase in the dissolution rate of efavirenz. HPβCD in combination with both PVP K30 and SLS gave highest enhancement (41.61 fold) in the dissolution rate of efavirenz. Combination of HPβCD with PVP K30 and SLS has markedly enhanced the solubility as well as dissolution rate of efavirenz than is possible with them individually. Hence a combination of HPβCD with PVP K30 and / or SLS is recommended to enhance the solubility and dissolution rate of efavirenz, a BCS class II drug.
ABSTRACT
BACKGROUND: Chronic irritant contact dermatitis, the common occupational dermatitis of the skin, could be caused by repetitive exposure of the skin to irritants. Adaptation of the skin to repeated influence of exogenous irritants is called the hardening. The defining characteristic of hardening phenomenon has been progressively decreasing inflammatory response with prolonged exposure to an irritant. OBJECTIVE: The purpose of this study was to evaluate the induction of hardening phenomenon by the repeated application of various concentrated sodium lauryl sulfate (SLS) solutions. METHODS: Once a day a 0.1%, 0.5%, 2% solution of SLS and distilled water were applied to the volar forearm skin in 15 healthy volunteers for 10 minutes over 3 weeks. After 3 weeks interval of rest, patch tests with 1% solution of SLS were conducted on previously irritated sites for 24 hours. We measured transepidermal water loss (TEWL) and erythema index (E-index) before irritation, during 3 weeks of repeated application. 4 days after the patches test, we measured TEWL and E-index once a day. RESULTS: During 3 weeks of irritation with repeated application of 0.1%, 0.5%, 2% SLS solution, increase of TEWL was accelerated according to concentrations of SLS. In the study of 24-h patch test with 1% SLS solution on previously irritated sites after 3 weeks interval of rest, TEWL on distilled water application site was significantly higher than other sites irritated with SLS solution on D44 and D45. The TEWL values on the site irritated with higher concentration of SLS solution were lower than those with lower concentration of SLS solution. In contrast, there were no significant differences in E-index value during 3 weeks of irritation and after 24-h patch test with 1% SLS solution. CONCLUSION: Hardening could be induced by repeated irritation with SLS solution for 3 weeks. We suggest that hardening could be induced more efficiently with the higher concentration of SLS solution than the lower concentration.
Subject(s)
Dermatitis, Contact , Dermatitis, Occupational , Erythema , Forearm , Irritants , Organ Preservation Solutions , Patch Tests , Skin , Sodium , Sodium Dodecyl Sulfate , Sucrose , WaterABSTRACT
Electrical impedance is one of the methods that have recently been applied to study the response of skin to an irritant stimulus...
Subject(s)
Electric Impedance , Skin Irritancy Tests , Spectrum AnalysisABSTRACT
OBJECTIVES: The purpose of the present study was to compare the general condition of peritonitis through a study of three connector systems : The Straight transfer set with Spike-and-Pork system(SPS), The Straight transfer set with Luer-Lock system(SLS), and The Y-set with Two Bag system(YS). METHODS: We reviewed our experience with 134 patients from 1988.1 to 1995.12. According to various kinds of connector system, we divided cases into 3 groups : The SPS(1988. 1-1991. 3) was used on 55 patients(mean age 47+/-2, M:F=30:25); The SLS(1991.4-1993.8) on 45 patients(mean age 55+/-1, M:F=30:15); and The YS(1993.9-1995.12) on 34 patients(mean age 49+/-5, M:F=15:19). RESULTS: 1) Total CAPD duration was 1.22 patient year in SPS, 1.08 in SLS, and 0.96 in YS. The incidence of peritonitis is 1.71 episodes per patient year in SPS, 1.03 in SLS, and 0.61 in YS. 2) Among the causative organisms of peritonitis, coagulase negative Staphylococcus was most common in the three groups(SPS:10.4%, SLS:10%, YS:20%). In SPS and SLS, S. aureus(7.7%, 8%), Pseudomonas(6.5%, 8%), E. coli(5.2%, 6%) were present in decreasing order. In YS, Pseudomonas (15%), S. aureus(15%), E. coli(10%) were present in decreasing order. There were no growth of organisms in 55.9% of SPS, 38% of SLS, and 30% of YS. 3) The probability of experiencing the first peritonitis at 1, 3, 6, and 12 months was 21.4%, 21.4%, 21.4%, and 23.9% respectively in SPS, 3.4%, 34.5%, 34.5%, and 10.3% respectively in SLS, and 0%, 28.5%, 35.7%, and 28.5% respectively in YS. 4) In the response to the treatment of peritonitis, 59.7% of the peritonitis episodes in SPS, 72% in SLS, and 85% in YS were cured with antibiotics. In 37.7% of the peritonitis episodes in SPS, 24% in SLS, and 10% in YS, the catheter was removed due to fungal, tubercolous, recurrent, or peritonitis not responding to antibiotics. 2 patients in SPS, 2 patients in SLS, and 1 patient in YS died due to peritonitis. 5) The catheter survival rate at 3, 6, 12 months was 72%, 63.6%, and 40% respectively in SPS, 89%, 78.3%, and 46.7% respectively in SLS, and 94%, 85.3%, and 76.6% respectively in YS. CONCLUSION: Our study suggests that there is a relationship between the development of connector system and a decrease of peritonitis in CAPD.