A novel pH-responsive hydrogel system based on Prunus armeniaca gum and acrylic acid: Preparation and evaluation as a potential candidate for controlled drug delivery

pH-responsive hydrogels have become effective and attractive materials for the controlled release of drugs at pre-determined destinations. In the present study, a novel hydrogel system based on Prunus armeniaca gum (PAG) and acrylic acid (AA) was prepared by a free radical mechanism using N, N-methylene bisacrylamide (MBA) as cross-linker and potassium persulfate (KPS) as initiator. A series of hydrogels varying PAG, AA, and MBA concentration was developed to determine the impact of these components. Formulated hydrogels were characterized for pH-responsive swelling, drug release, gel content, and porosity. Structural analysis was performed by FTIR, XRD, and SEM analysis. TGA study was applied to assess thermal stability. Oral acute toxicity and in vivo drug release were performed in rabbits. Hydrogels exhibited pH-dependent swelling and drug release. Swelling, drug loading and release, and porosity increased by increasing PAG and AA concentration while decreased by increasing MBA. The gel content of formulations was increased by increasing all three components. FTIR studies confirmed the development of copolymeric networks and the loading of drug. XRD studies revealed that hydrogels were amorphous, and the crystalline drug was changed into an amorphous form during loading. TGA results indicated that hydrogels were stable up to 600 °C. Acute oral toxicity results confirm that hydrogels were nontoxic up to a dose of 2 g/kg body weight in rabbits. The pharmacokinetic evaluation revealed that hydrogels prolonged the availability of the drug and the peak plasma concentration of the drug was obtained in 6 h as compared to the oral solution of the drug. Tramadol hydrochloride (THC) was used as a model drug. Hence, pH-responsive swelling and release, nontoxic nature and improved pharmacokinetics support that PAG-based hydrogels may be considered as potential controlled-release polymeric carriers.

Al3+/Ca2+ cross-linked hydrogel matrix tablet of etherified tara gum for sustained delivery of tramadol hydrochloride in gastrointestinal milieu

Tara gum (TG) was derivatized to carboxymethyl TG (CMTG) and then cross-linked with Al³⁺/Ca²⁺ ions to prepare Al/Ca cross-linked CMTG matrices for sustained delivery of Tramadol Hydrochloride (TH), a highly water-soluble drug. The effect of Al³⁺/Ca²⁺ ions concentration on swelling, erosion, and drug release behavior from Al/Ca-CMTG matrices was investigated. Al-CMTG matrices had greater cross-linking density, produced a more rigid and denser hydrogel layer than Ca-CMTG matrices. The rate of swelling, erosion, and in vitro drug release from Al-CMTG matrices was slower than from Ca-CMTG matrices. The most important finding of our study indicated that at the same concentration of cross-linking ions, the release of TH from Al-CMTG matrices was slower compared to Ca-CMTG matrices. The optimized formulation containing 9 % w/w AlCl₃ in CMTG matrices released TH in a sustained manner up to 12 h in the gastrointestinal milieu. Moreover, it was observed that the prepared optimized formulation exhibited a more sustained release of TH compared to the marketed product.

Preparation and Evaluation of Hydrogel Film Containing Tramadol for Reduction of Peripheral Neuropathic Pain

To develop and assess new dosage forms for the alternative to existing oral medication for peripheral neuropathy, a hydrogel film in the skin patch formation containing tramadol hydrochloride (TRA), a water-soluble drug used as an analgesic, was prepared and evaluated. A hydrogel film composed of 20%(w/w) hydroxypropyl methylcellulose (HPMC) irradiated with electron beams had high transparency and elasticity similar to commercially available wound dressings and soft tissues, suggesting that it is a suitable substrate for TRA. The inclusion of TRA was enabled by immersing the HPMC hydrogel film in TRA aqueous solution. The release and skin permeation of TRA from TRA-containing hydrogel films differed depending on the electron beam dose. Moreover, the analgesic effects in mice were confirmed in a dose-dependent manner. This study demonstrated the usefulness of a hydrogel film containing TRA as a new dosage form alternative to the existing oral medication for peripheral neuropathy.

Effects of topical application of tramadol with/without dexmedetomidine and proparacaine on corneal sensitivity in rats

PURPOSE

To evaluate the corneal anesthetic effect following topical application of tramadol alone and in combination with dexmedetomidine, and compare it to proparacaine, in clinically healthy rats.

METHODS

A randomized, crossover study was performed. Twenty Wistar albino rats (n = 40 eyes) were used. Corneal touch threshold (CTT) measurements (in mm) were obtained using a Cochet-Bonnet aesthesiometer. CTT measurements were obtained at baseline, 1-min following application of the topical anesthetic agent, and repeated at 5-min intervals up to 75 min. The topical protocol involved 3 treatment conditions, separated by a 2-week washout period: proparacaine, tramadol alone, and tramadol in combination with dexmedetomidine.

RESULTS

CTT values were significantly decreased compared to baseline at each timepoint until completion of the 75-min evaluation in all treated eyes, regardless of the assigned treatment (p < 0.0083). With tramadol, complete corneal anesthesia (CTT = 0) was achieved within 1-5 min in 18 eyes and ranged from 5 to 25 min. Co-administration of dexmedetomidine to tramadol resulted in significantly increased CTT values from 5 to 20 min following topical application, compared to tramadol alone (p < 0.0083), and complete corneal anesthesia was achieved in only 14 out of 20 treated eyes.

CONCLUSION

Tramadol might be a useful alternative to topical anesthetic agents, providing a dose-related corneal anesthetic effect. Co-administration of dexmedetomidine does not potentiate its anesthetic effect. The underlying mechanism(s) of drug antagonism between tramadol and dexmedetomidine remains to be determined.

The effect of alcohol on ionizing and non-ionizing drug release from hydrophilic, lipophilic and dual matrix tablets

The aim of this work was to investigate and quantitatively evaluate the effect of presence of alcohol on in vitro release of ionizing and non-ionizing drug from hydrophilic, lipophilic and hydrophilic-lipophilic matrix tablets. The Food and Drug Administration (FDA) recommends in vitro dissolution testing of extended release formulations in ethanolic media up to 40% because of possible alcohol-induced dose dumping effect. This study is focused on comparison of the dissolution behavior of matrix tablets (based on hypromellose and/or glyceryl behenate as retarding agent) of the same composition containing different type of drug – ionizing tramadol hydrochloride (TH) and non-ionizing pentoxifylline (PTX). The dissolution tests were performed in acidic medium (pH 1.2) and in alcoholic medim (20%, 40% of ethanol) and the changes of tablets were observed also photographically.

It was found that the alcohol resistence of the hydrophilic-lipophilic formulations with TH and the hydrophilic-lipophilic formulations with PTX containing a higher amount of hypromellose does not reflect the alcohol resistence of the formulations with pure hypromellose or glyceryl behenate. Both hydrophilic-lipophilic formulation with TH and more lipophilic formulation with PTX show significant alcohol dose dumping effect.

Tramadol hydrochloride 75 mg/dexketoprofen 25 mg oral fixed-dose combination in moderate-to-severe acute pain: sustained analgesic effect over a 56-h period in the postoperative setting

Multimodal analgesia constitutes a common strategy in pain management. A tramadol hydrochloride 75 mg/dexketoprofen 25 mg oral fixed combination (TRAM/DKP 75 mg/25 mg) has been recently registered and released in Europe for the treatment of moderate-to-severe acute pain. This paper provides additional analyses on the results of two phase III clinical trials (DEX-TRA-04 and DEX-TRA-05) on postoperative pain to document its sustained effect. The analysis was applied to a modified intention-to-treat population (mITT, n = 933) of patients undergoing active treatment from the first dose, to assess the sustained effect of TRAM/DKP 75 mg/25 mg on pain intensity (PI-VAS 0-100) over 56 h from first drug intake. The superior analgesic effect of TRAM/DKP 75 mg/25 mg over 56 h in terms of difference in PI-VAS (mean [SE]) was shown for DEX-TRA-04 (-11.0 [0.55] over dexketoprofen 25 mg and -9.1 [0.55] over tramadol 100 mg, P ≤ 0.0001) and for DEX-TRA-05 (-10.4 [0.51] over dexketoprofen 25 mg and -8.3 [0.51] over tramadol 100 mg, P ≤ 0.0001). The statistical analysis performed on data coming from both studies confirms the superior sustained analgesia of TRAM/DKP 75 mg/25 mg over tramadol 100 mg and dexketoprofen 25 mg. These results are consistent with the previously published data obtained on the ITT population and strongly support the role of this oral fixed-dose combination in the treatment of moderate-to-severe acute pain.

Scrolls: novel microparticulate systems for enhanced delivery to/across the skin

We describe the scroll system as a new microparticulate structured delivery system for enhanced delivery to/across the skin. The basic components of the scroll system are non-ionic surface active of the type of alkyl polyglycol ethers and a glycol. The unique structures are preserved with addition of various ingredients such as polymers, vegetable oils, pharmaceuticals, and permeation enhancers but are dismissed when amphiphile is withdrawn. The microparticles have a unique scroll structure with multiple "wrapping." Besides enabling superior permeation of drugs into/across the skin, the drugs delivered by scroll systems were more effective in vitro and in vivo compared to controls. Model drugs presented high entrapment capacity in scroll systems. The systems are stable over time and are safe for skin application. In order to form, they require a small number of ingredients, simple preparation method, and are environment friendly. The scroll systems may be new potential tools in the dermal/transdermal pharmaceutical and cosmetic industry.

Overall safety profile and effectiveness of tramadol hydrochloride/acetaminophen in patients with chronic noncancer pain in Japanese real-world practice

OBJECTIVE

To evaluate the overall safety profile and clinical effectiveness of tramadol hydrochloride/acetaminophen (TA) combination tablets in Japanese patients with chronic noncancer pain unrelieved by non-opioid drugs for up to 12 weeks in real-world practice.

RESEARCH DESIGN AND METHODS

This survey was a multicenter, prospective, longitudinal registry on the use of TA as a newly initiated pain treatment for chronic noncancer pain incurable by non-opioid analgesics that was conducted under the Good Post Marketing Study Practice regulation controlled by the Japan Ministry of Health, Labor and Welfare. Collected data included socio-demographics, treatment information, incidence of adverse drug reactions (ADRs), numerical rating scale for intensity of pain, EuroQol-5D (EQ-5D) scale, and physician's global impression (PGI) during the 12 week observation period.

RESULTS

A total of 1316 patients were registered. ADRs were reported in 259 patients (20.5%); most events were nonserious (99.4%), including nausea (n = 87 [6.9%]), constipation (n = 63 [5.0%]), dizziness and somnolence (n = 29 [2.3%] each), and vomiting (n = 21 [1.7%]). No event related to drug dependence or respiratory depression was reported. In addition, 82.8% of patients showed acceptable effectiveness based on PGI at Week 4. Numerical rating scale for intensity of pain and EQ-5D utility scores were improved by -2.7 (SD 2.3) and 0.16 (SD 0.20) at Week 4, respectively, and the improvement was maintained until Week 12.

CONCLUSION

This is a first report to evaluate the risk-benefit profile of TA in Japanese real-world practice using large size registry data. It is suggested that the favorable risk-benefit balance of TA was confirmed for patients with chronic noncancer pain unrelieved by non-opioid drugs in real-world practice. Limitations of this study were those inherent to open-label and non-interventional study designs.

TRIAL REGISTRATION

This registry survey is registered at umin.ac.jp (identifier: UMIN000015901).

Synthesis and evaluation of chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) as a drug carrier for controlled release of tramadol hydrochloride

Chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) has been synthesized for different feed ratios of 2-hydroxyethyl methacrylate and itaconic acid and characterized by FT-IR, thermogravimetry and swelling in simulated biological fluids (SBF) and evaluated as a drug carrier with model drug, tramadol hydrochloride (TRM). Grafting decreased the thermal stability of chitosan. FT-IR spectra of tablet did not reveal any molecular level (i.e. at <10 nm scale) drug-polymer interaction. But differential scanning calorimetric studies indicated a probable drug-polymer interaction at a scale >100 nm level. The observed Korsmeyer-Peppas's power law exponents (0.19-1.21) for the in vitro release profiles of TRM in SBF and other drugs such as 5-fluorouracil (FU), paracetamol (PCM) and vanlafaxine hydrochloride (VNF) with the copolymer carriers revealed an anomalous drug release mechanism. The decreased release rates for the grafted chitosan and the enhanced release rate for the grafts with increasing itaconic acid content in the feed were more likely attributed to the enhanced drug-matrix interaction and polymer-SBF interactions, respectively. The different release profiles of FU, PCM, TRM and VNF with the copolymer matrix are attributed to the different chemical structures of drugs. The above features suggest the graft copolymer's candidature for use as a promising oral drug delivery system.

Application of HPLC for the simultaneous determination of aceclofenac, paracetamol and tramadol hydrochloride in pharmaceutical dosage form

A simple, precise and accurate reversed-phase liquid chromatographic method has been developed for the simultaneous estimation of aceclofenac (ACF), paracetamol (PCM) and tramadol hydrochloride (TRM) in pharmaceutical dosage form. The chromatographic separation was achieved on a HiQ-Sil™ HS C18 column (250×4.6 mm i.d., 5 μm particle size), kromatek analytical column at ambient temperature. The mobile phase consisted of 40: 60 (v/v); phosphate buffer (pH 6.0): methanol. The flow rate was set to 1.0 mL min⁻¹ and UV detection was carried out at 270 nm. The retention time (t_R) for ACF, PCM and TRM were found to be 14.567 ± 0.02, 3.133 ± 0.01 and 7.858 ± 0.02 min, respectively. The validation of the proposed method was carried out for linearity, precision, robustness, limit of detection, limit of quantitation, speci city, accuracy and system suitability. The linear dynamic ranges were from 40–160 μg mL⁻¹ for ACF, 130–520 μg mL⁻¹ for PCM and 15–60 μg mL⁻¹ for TRM. The developed method can be used for routine quality control analysis of titled drugs in pharmaceutical dosage form.