Tramadol encapsulated into polyhydroxybutyrate microspheres: in vitro release and epidural analgesic effect in rats

Biomedical applications of environmental friendly poly-hydroxyalkanoates

Biological polyesters of hydroxyacids are known as polyhydroxyalkanoates (PHA). They have proved to be an alternative, environmentally friendly and attractive candidate for the replacement of petroleum-based plastics in many applications. Many bacteria synthesize these compounds as an intracellular carbon and energy compound usually under unbalanced growth conditions. Biodegradability and biocompatibility of different PHA has been studied in cell culture systems or in an animal host during the last few decades. Such investigations have proposed that PHA can be used as biomaterials for applications in conventional medical devices such as sutures, patches, meshes, implants, and tissue engineering scaffolds as well. Moreover, findings related to encapsulation capability and degradation kinetics of some PHA polymers has paved their way for development of controlled drug delivery systems. The present review discusses about bio-plastics, their characteristics, examines the key findings and recent advances highlighting the usage of bio-plastics in different medical devices. The patents concerning to PHA application in biomedical field have been also enlisted that will provide a brief overview of the status of research in bio-plastic. This would help medical researchers and practitioners to replace the synthetic plastics aids that are currently being used. Simultaneously, it could also prove to be a strong step in reducing the plastic pollution that surged abruptly due to the COVID-19 medical waste.

Polyhydroxyalkanoate (PHA): applications in drug delivery and tissue engineering

INTRODUCTION

The applications of naturally obtained polymers are tremendously increased due to them being biocompatible, biodegradable, environmentally friendly and renewable in nature. Among them, polyhydroxyalkanoates are widely studied and they can be utilized in many areas of human life research such as drug delivery, tissue engineering, and other medical applications.

AREAS COVERED

This review provides an overview of the polyhydroxyalkanoates biosynthesis and their possible applications in drug delivery in the range of micro- and nano-size. Moreover, the possible applications in tissue engineering are covered considering macro- and microporous scaffolds and extracellular matrix analogs.

EXPERT COMMENTARY

The majority of synthetic plastics are non-biodegradable so, in the last years, a renewed interest is growing to develop alternative processes to produce biologically derived polymers. Among them, PHAs present good properties such as high immunotolerance, low toxicity, biodegradability, so, they are promisingly using as biomaterials in biomedical applications.

Newly developed controlled release subcutaneous formulation for tramadol hydrochloride

This study presents a drug delivery system of poly (Ɛ-caprolactone) (PCL) ribbons to optimize the pharmaceutical action of tramadol for the first time according to our knowledge. PCL ribbons were fabricated and loaded with tramadol HCl. Ribbons were prepared by slip casting technique and coated with dipping technique with β-cyclodextrin. The chemical integrity and surface morphology of the ribbons were confirmed using FTIR and SEM coupled with EDX. In addition, thermodynamic behavior of the fabricated ribbons was investigated using DSC/TGA. Tramadol loading into PCL ribbons, biodegradation of ribbons and tramadol release kinetics were studied in PBS.The results revealed that the formulated composition did not affect the chemical integrity of the drug. Furthermore, SEM/EDX confirmed the inclusion of tramadol into the PCL matrix in homogenous distribution pattern without any observation of porous structure. The particle size of loaded tramadol was found to be in the range of (2-4 nm). The formulated composition did not affect the chemical integrity of the drug and should be further investigated for bioavailability. Tramadol exhibited controlled release behavior from PCL ribbons up to 45 days governed mainly by diffusion mechanism. The fabricated ribbons have a great potentiality to be implemented in the long term subcutaneous delivery of tramadol.

Pharmacokinetics and Pharmacodynamics Evaluation of Tramadol in Thermoreversible Gels

We evaluated pharmacokinetics (PK) and pharmacodynamics (PD) induced by new formulations of tramadol (TR) in thermoreversible gels. The poloxamer- (PL-) tramadol systems were prepared by direct dispersion of the drug in solutions with PL 407 and PL 188. The evaluated formulations were as follows: F1: TR 2% in aqueous solution and F2: PL 407 (20%) + PL 188 (10%) + TR 2%; F3: PL 407 (25%) + PL 188 (5%) + TR 2%; F4: PL 407 (20%) + TR 2%. New Zealand White rabbits were divided into four groups (n = 6) and treated by subcutaneous route with F1, F2, F3, or F4 (10 μg·kg^-1). PK evaluation used TR and M1 plasma levels. PD evaluation was performed with the measurement of both pupils' diameters. F2 showed higher TR plasma concentration after 180 minutes and presented lower M1 concentrations at almost all evaluated periods. Areas under the curve (ASC_0-480 and ASC_0-∞ ) and clearance of F2 presented differences compared to F1. F2 presented significant correlation (Pearson correlation) between the enhancement of TR and M1 concentrations and the decrease of pupil size (miosis). Thus, F2 was effective in altering pharmacokinetics and pharmacodynamics effects of TR.

Poloxamer-based binary hydrogels for delivering tramadol hydrochloride: sol-gel transition studies, dissolution-release kinetics, in vitro toxicity, and pharmacological evaluation

In this work, poloxamer (PL)-based binary hydrogels, composed of PL 407 and PL 188, were studied with regard to the physicochemical aspects of sol-gel transition and pharmaceutical formulation issues such as dissolution-release profiles. In particular, we evaluated the cytotoxicity, genotoxicity, and in vivo pharmacological performance of PL 407 and PL 407-PL 188 hydrogels containing tramadol (TR) to analyze its potential treatment of acute pain. Drug-micelle interaction studies showed the formation of PL 407-PL 188 binary systems and the drug partitioning into the micelles. Characterization of the sol-gel transition phase showed an increase on enthalpy variation values that were induced by the presence of TR hydrochloride within the PL 407 or PL 407-PL 188 systems. Hydrogel dissolution occurred rapidly, with approximately 30%-45% of the gel dissolved, reaching ~80%-90% up to 24 hours. For in vitro release assays, formulations followed the diffusion Higuchi model and lower K(rel) values were observed for PL 407 (20%, K(rel) = 112.9 ± 10.6 μg · h(-1/2)) and its binary systems PL 407-PL 188 (25%-5% and 25%-10%, K(rel) =80.8 ± 6.1 and 103.4 ± 8.3 μg · h(-1/2), respectively) in relation to TR solution (K(rel) =417.9 ± 47.5 μg · h(-1/2), P<0.001). In addition, the reduced cytotoxicity (V79 fibroblasts and hepatocytes) and genotoxicity (V79 fibroblasts), as well as the prolonged analgesic effects (>72 hours) pointed to PL-based hydrogels as a potential treatment, by subcutaneous injection, for acute pain.

Analgesic effects of intrathecal tramadol in patients undergoing caesarean section: a randomised, double-blind study

BACKGROUND

Intrathecal tramadol combined with local anaesthetics has been used for postoperative analgesia following lower abdominal and perineal surgery. The present study evaluated the effect of intrathecal tramadol on spinal block characteristics and neonatal outcome after elective caesarean section.

METHODS

Eighty full-term parturients scheduled for elective caesarean section were randomly divided into two groups. In the fentanyl group, patients received intrathecal 0.5% bupivacaine 10 mg with fentanyl 10 μg; in the tramadol group, patients were given the same dose of bupivacaine with tramadol 10 mg. Sensory and motor block characteristics, duration of postoperative analgesia, maternal side effects, and neonatal outcome were compared.

RESULTS

One patient in the tramadol group and two patients in the fentanyl group were excluded from data analysis. Median [interquartile range] duration of postoperative analgesia in the tramadol and the fentanyl groups was 300 [240-360] min and 260 [233-300] min respectively (P = 0.02). The incidence of shivering was lower in patients who received tramadol (5%) than those who had fentanyl (32%) (P = 0.003). Apgar scores, umbilical cord acid-base measurement and neurologic and adaptive capacity scores were comparable between the two groups.

CONCLUSION

Compared to intrathecal fentanyl 10 μg, tramadol 10 mg, as an adjunct to bupivacaine for subarachnoid block for caesarean section, showed a longer duration of analgesia with a reduced incidence of shivering.

Microparticles prepared from biodegradable polyhydroxyalkanoates as matrix for encapsulation of cytostatic drug

Microparticles made from degradable polyhydroxyalkanoates of different chemical compositions a homopolymer of 3-hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids (P3HB/4HB), 3-hydroxybutyric and 3-hydroxyvaleric acids (P3HB/3HV), 3-hydroxybutyric and 3-hydroxyhexanoic acids (P3HB/3HHx) were prepared using the solvent evaporation technique, from double emulsions. The study addresses the influence of the chemical compositions on the size and ξ-potential of microparticles. P3HB microparticles loaded with doxorubicin have been prepared and investigated. Their average diameter and ξ-potential have been found to be dependent upon the level of loading (1, 5, and 10 % of the polymer mass). Investigation of the in vitro drug release behavior showed that the total drug released from the microparticle into the medium increased with mass concentration of the drug. In this study mouse fibroblast NIH 3T3 cells were cultivated on PHA microparticles, and results of using fluorescent DAPI DNA stain, and MTT assay showed that microparticles prepared from PHAs of different chemical compositions did not exhibit cytotoxicity to cells cultured on them and proved to be highly biocompatible. Cell attachment and proliferation on PHA microparticles were similar to those on polystyrene. The cytostatic drug encapsulated in P3HB/3HV microparticles has been proven to be effective against HeLa tumor cells.

Tramadol in pregnancy and lactation

Tramadol produces analgesic effects through both non-opioid and weak opioid activity and is commonly used to treat mild to moderate pain. It has been in use for over 30 years and has a well-established safety profile in the general population. Since tramadol is not licensed for use in pregnancy and lactation, there is limited clinical research on its use in this patient population. A systematic review was undertaken of articles published in English before June 2011, searching Pubmed, Medline, CINAHL, Embase and Cochrane databases using the terms 'tramadol and pregnancy', 'tramadol and breastfeeding', 'tramadol and lactation', and 'tramadol and neonate'.

Poly(3-hydroxybutyrate) and biopolymer systems on the basis of this polyester

Biodegradable biopolymers attract much attention in biology and medicine due to its wide application. The present review is designed to be a comprehensive source for research of biodegradable and biocompatible bacterial polymer, poly(3-hydroxybutyrate). This paper focuses on basic properties of biopolymer: biodegradability and biocompatibility, as well as on biopolymer systems: various materials, devices and compositions on the basis of biopolymer. Application of biopolymer systems based on poly(3-hydroxybutyrate) in medicine as surgical implants, in bioengineering as scaffold for cell cultures, and in pharmacy as drug dosage forms and drug systems is observed in the present review.

Levobupivacaine-tramadol combination for caudal block in children: a randomized, double-blinded, prospective study

BACKGROUND

The aim of this prospective study was to compare the postoperative analgesic efficacy and duration of analgesia after caudal levobupivacaine 0.125% or caudal tramadol 1.5 mg.kg(-1) and mixture of both in children undergoing day-case surgery.

METHODS

Sixty-three American Society of Anesthesiologists (ASA) I or II children between 1 and 7 years old scheduled for inguinal hernia repair under sevoflurane anesthesia were randomized to receive caudal levobupivacaine 0.125% (group L), caudal tramadol 1.5 mg.kg(-1) (group T) or mixture of both (group LT) (total volume of caudal solution was 1 ml.kg(-1)). Duration of analgesia and requirement for additional analgesics were noted. Postoperative pain was evaluated using the Children's and Infants' Postoperative Pain Scale (CHIPPS) every 15 min for the first hour, and after 2, 3, 4, 6, 12, and 24 h. Analgesia was supplemented whenever pain score was > or =4.

RESULTS

No patient experienced significant intraoperative hemodynamic response to surgical incision. Duration of analgesia was significantly longer in group LT than in group L and group T (545 +/- 160 min vs 322 +/- 183 min and 248 +/- 188 min, respectively) (P < 0.01). There were no significant differences between the group L and group T for duration of analgesia (P > 0.05). There were no significant differences among the groups in the number of patients requiring analgesia after operation (P = 0.7). No signs of motor block were observed after the first postoperative hour in any of the patients.

CONCLUSION

Addition of tramadol increased the duration of analgesia produced by caudal levobupivacaine in children.

Biocompatibility of polyhydroxybutyrate microspheres: in vitro and in vivo evaluation

Microspheres have been prepared from the resorbable linear polyester of beta-hydroxybutyric acid (polyhydroxybutyrate, PHB) by the solvent evaporation technique and investigated in vitro and in vivo. Biocompatibility of the microspheres has been proved in tests in the culture of mouse fibroblast cell line NIH 3T3 and in experiments on intramuscular implantation of the microspheres to Wistar rats for 3 months. Tissue response to the implantation of polymeric microspheres has been found to consist in a mild inflammatory reaction, pronounced macrophage infiltration that increases over time, involving mono- and poly-nuclear foreign body giant cells that resorb the polymeric matrix. No fibrous capsules were formed around polymeric microparticles; neither necrosis nor any other adverse morphological changes and tissue transformation in response to the implantation of the PHB microparticles were recorded. The results of the study suggest that polyhydroxybutyrate is a good candidate for fabricating prolonged-action drugs in the form of microparticles intended for intramuscular injection.

Polymer-based biodegradable drug delivery systems in pain management

Pain is an unpleasant sensory experience commonly produced by damage to bodily tissues and it is one of the most significant public health problems, because 21.5% of the world population is estimated to suffer from pain. It results in a total loss of more than 165 billion US dollars each year in the United States alone. Pain reflects a mixture of various pathophysiologic, psychologic, and genetic contributions. When undertreated, pain usually results in serious immune and metabolic upset. Therefore, it requires wide understanding and intensive effort for a better management. Currently, pain control is limited by the modest efficiency of the used drugs, the serious side effects of these drugs, and the inefficacy of conventional drug administration. By the introduction of the technology of biodegradable controlled-release devices into clinical practice, pain control not only benefits from these novel methods for a better delivery of various drugs, but the side effects of the drugs are reduced because use of the devices improves patient compliance. Biodegradable controlled-release devices are polymer-based devices that are designed to deliver drugs locally in a predesigned manner. Recently, there was a high interest in developing these devices for the delivery of different drugs used for pain control. This paper first highlights the dimensions and basics of the problem of pain. Then, it presents an overview of the biodegradable polymers that are used in drug delivery systems and summarizes the studies carried out on these systems in the field of pain management. We refer to our experience in developing a device for multimodal drug delivery, including the use of nanotechnology. Future perspectives are also presented.

What’s new and novel in obstetric anesthesia? Contributions from the 2003 scientific literature

THE PREGNANT PATIENT: Age; maternal disease; prophylactic antibiotics; gastroesophageal reflux; obesity; starvation; genotyping; coagulopathy; infection; substance abuse; altered drug responses in pregnancy; physiological changes of pregnancy. THE FETUS: Fetal monitoring; intrauterine surgery. THE NEWBORN: Breastfeeding; maternal infection, fever, and neonatal sepsis evaluation. OBSTETRIC COMPLICATIONS: Embolic phenomena; hemorrhage; preeclampsia; preterm delivery. OBSTETRIC MANAGEMENT: External cephalic version and cervical cerclage; elective cesarean delivery; fetal malpresentation; vaginal birth after cesarean delivery; termination of pregnancy. OBSTETRIC ANESTHESIA: Analgesia for labor and delivery; anesthesia for cesarean delivery; anesthesia for short obstetric operations; complications of anesthesia. MISCELLANEOUS: Consent; ethics; history; labor support; websites/books/leaflets/journal announcements.