Persistence of immunity and impact of a third (booster) dose of an inactivated SARS-CoV-2 vaccine, BBV152; a phase 2, double-blind, randomised controlled trial

BackgroundNeutralising antibody responses to SARS-CoV-2 vaccines have been reported to decline within 6 months of vaccination, particularly against Variants of Concern (VOC). We assessed the immunogenicity and safety of a booster dose of BBV152 administered 6 months after the second of a two-dose primary vaccination series. MethodsIn an ongoing phase 2 trial (ClinicalTrials.gov: NCT04471519) the protocol was amended after six months to re-consent and randomise 184 previously vaccinated participants to receive a third dose of vaccine or placebo on Day 215. The primary outcome was to measure neutralising antibody titres by plaque-reduction neutralisation test (PRNT50) four weeks after the booster; safety as serious adverse events (SAE) was the key secondary outcome. FindingsFour weeks after a second BBV152 vaccination geometric mean titres (GMTs) of neutralising antibodies were 197{middle dot}0 PRNT50 (95% CI: 155{middle dot}6-249{middle dot}4); this level declined to 23{middle dot}9 PRNT50 (14{middle dot}0-40{middle dot}6) six months later, with a seroconversion rate of 75{middle dot}4% (95% CI: 68{middle dot}4-81{middle dot}6). Four weeks after booster vaccination the GMT increased on Day 243 to 746{middle dot}6 PRNT50 (514{middle dot}9-1081) compared with 100{middle dot}7 PRNT50 (43{middle dot}6-232{middle dot}6) in the placebo group. Corresponding seroconversion rates were 98{middle dot}7% (92{middle dot}8-99{middle dot}9) and 79{middle dot}8% (69{middle dot}6-87{middle dot}8). Increased titres in the placebo group were attributed to natural infection as the study was conducted during the second wave of COVID-19 in India. PRNT50 titres against the SARS-CoV-2 variants increased--Alpha (32{middle dot}6-fold), Beta (161{middle dot}0-fold), Delta (264{middle dot}7-fold), and Delta plus (174{middle dot}2-fold)--after the booster vaccination. We found that vaccine induces both memory B and T cells with a distinct AIM+ specific CD4+T central and effector memory phenotype, including CD8+ TEMRA phenotype. Reactogenicity after vaccine and placebo was minimal and comparable, and no SAEs were reported. InterpretationSix months after a two-dose BBV152 vaccination series cell mediated immunity and neutralising antibodies to both homologous (D614G) and heterologous strains (Alpha, Beta, Delta and Delta plus) persisted above baseline, although the magnitude of the responses had declined. Neutralising antibodies against homologous and heterologous SARS-CoV-2 variants increased 19- to 97-fold after a third vaccination. Booster BBV152 vaccination is safe and may be necessary to ensure persistent immunity to prevent breakthrough infections. FundingThis work was supported and funded by Bharat Biotech International Limited.

Efficacy, safety, and lot to lot immunogenicity of an inactivated SARS-CoV-2 vaccine (BBV152): a double-blind, randomised, controlled phase 3 trial

BackgroundWe report the clinical efficacy against COVID-19 infection of BBV152, a whole-virion inactivated SARS-CoV-2 vaccine formulated with a Toll-like receptor 7/8 agonist molecule adsorbed to alum (Algel-IMDG). MethodsWe did a double-blind, randomised, multicentre, phase 3 clinical trial in 25 Indian hospitals to evaluate the efficacy, safety, and immunological lot consistency of BBV152. Healthy adults (age 18-98 years) randomised 1:1 using a computer-generated randomisation scheme received two intramuscular doses of vaccine or placebo administered four weeks apart. The primary outcome was laboratory-confirmed symptomatic COVID-19, occurring at least 14 days after the second dose. Secondary outcomes were efficacy in sub-groups for age (18-< 60 years and [≥] 60 years) and in participants with pre-existing stable medical conditions. We also evaluated safety, reactogenicity, and consistency of immune responses for three consecutive manufacturing lots. FindingsBetween November 16, 2020 and January 7, 2021 we recruited 25,798 participants who were randomised to BBV152 or placebo groups; 24,419 received two doses of BBV152 (n = 12,221) or placebo (n = 12,198). In a case-driven analysis, 130 cases of symptomatic COVID-19 were reported in 16,973 (0{middle dot}77%) participants with follow-up at least two weeks after the second vaccination; 24 occurred in the vaccine group and 106 in placebo recipients giving an overall vaccine efficacy of 77{middle dot}8% (95% CI: 65{middle dot}2-86{middle dot}4). Sixteen cases, one vaccinee and 15 placebo recipients, met the severe symptomatic COVID-19 case definition giving a vaccine efficacy of 93{middle dot}4% (57{middle dot}1-99{middle dot}8). Efficacy against asymptomatic COVID-19 was 63{middle dot}6% (29{middle dot}0-82{middle dot}4). BBV152 conferred 65{middle dot}2% (95% CI: 33{middle dot}1-83{middle dot}0) protection against the SARS-CoV-2 Variant of Concern, B.1.617.2 (Delta). BBV152 was well tolerated with no clinically or statistically significant differences in the distributions of solicited, unsolicited, or serious adverse events between vaccine and placebo groups. No cases of anaphylaxis or vaccine-related deaths were reported. InterpretationBBV152 was immunogenic and highly efficacious against symptomatic and asymptomatic COVID-19 variant associated disease, particularly against severe disease in adults. Vaccination was well tolerated with an overall incidence of adverse events observed over a median of 146 days that was lower than that observed with other COVID-19 vaccines. FundingThis work was supported and funded by Bharat Biotech International Limited and partly co-funded by the Indian Council of Medical Research. Clinicaltrials.gov: NCT04641481

Critical interactions between opioid and cannabinoid receptors during tolerance and physical dependence development to opioids in the murine gastrointestinal tract: proof of concept.

INTRODUCTION: Tolerance (TOL) and physical dependence (PD) constitute important limitations of opioid therapy. The aim of our study was to validate research tools to investigate TOL and PD and to characterize the interactions between opioid (OR) and cannabinoid (CB) receptors in these processes in the GI tract. METHODS: TOL was assessed through the comparison of morphine ability to inhibit electrically evoked smooth muscles contractility in the mouse ileum that was previously incubated with/without morphine for 1 h. To evaluate the PD, the ileum was incubated with morphine for 10 min, then challenged with naloxone to induce withdrawal response (WR). The OR/CB interactions were evaluated using mixed agonist (PR-38) and AM-251 (CB1 antagonist). RESULTS: The inhibitory effect of morphine on ileal contractions was weaker in tissue incubated with this opioid than in tissue incubated without opioid. The opposite was noted for PR-38. In tissues exposed to morphine, but not to PR-38, naloxone induced a WR. The blockage of CB1 receptors with AM-251 before the addition of PR-38 resulted in a naloxone-induced WR. CONCLUSION: The co-activation of OR and CB reduced development of TOL and PD to opioids in the mouse GI tract and mixed OR/CB agonists are promising alternative to currently used opioid drugs.

Improved Dissolution Rate and Intestinal Absorption of Fexofenadine Hydrochloride by the Preparation of Solid Dispersions: In Vitro and In Situ Evaluation.

The objective of this study was to enhance dissolution and permeation of a low soluble, absorbable fexofenadine hydrochloride (FFH) by preparing solid dispersions using polyethylene glycol 20,000 (PEG 20,000) and poloxamer 188 as carriers. The phase solubility measurement for the supplied FFH revealed a linear increase in the solubility of fexofenadine with increasing carrier concentration in water (1.45 mg/mL to 11.78 mg/mL with 0% w/v to 30% w/v PEG 20,000; 1.45 mg/mL to 12.27 mg/mL with 0% w/v to 30% w/v poloxamer 188). To select the appropriate drug carrier concentration, a series of solid dispersions were prepared in the drug carrier weight ratios of 1:1, 1:2 and 1:4 by fusion method. The solid dispersions composed of drug carrier at 1:4 weight ratio showed highest dissolution with the time required for the release of 50% of the drug <15 min compared to the supplied FFH (>120 min). The intestinal absorption study presented a significant improvement in the absorption of drug from the solid dispersions composed of poloxamer 188 than PEG 20,000. In summary, the solid dispersions of FFH prepared using PEG 20,000 and poloxamer 188 demonstrated improved dissolution and absorption than supplied FFH and could be used to improve the oral bioavailability of fexofenadine.

GSK-3 Inhibitors as New Leads to Treat Type-II Diabetes.

In India as well as globally, diabetes is in a state of high risk and next to cardiovascular disease. As per the WHO, the risk of diabetes is expected to rise about 511 million by 2030. In quest of novel targets for type-2 diabetes, many targets were elucidated, such as Glycogen Synthase Kinase-3 (GSK-3), Dipeptidyl Peptidase (DPP-IV), PPAR-γ, α-Glucosidase, α-Amylase, GLP-1, and SGLT. Among the targets, GSK-3 was reported to be an effective target for the treatment of diabetes. In the metabolism of glycogen, GSK is a regulatory enzyme for the biosynthesis of glycogen (glycogenesis). It catalyzes the synthesis of a linear unbranched molecule with 1,4-α-glycosidic linkages. GSK-3 family has two isoenzymes, namely α and ß, which differ in their Nand C- terminal sequences and are semi-conservative multifunctional serine/threonine kinase enzymes. In this chapter, we discuss an overview of general diabetic mechanisms and how GSK-3 modulation may influence these processes. Mutation in the GSK-3 complex causes diabetes. Synthetic and natural scaffolds modulate GSK-3 against diabetes and leading to its optimization for the development of GSK-3 inhibitors. This review mainly focuses on the development of GSK-3 inhibitors and highlights current and potential future therapeutic approaches that support the notion of targeting glucose metabolism with novel antidiabetic agents.

Myoclonus-Ataxia Syndrome Associated with COVID-19

Neurological manifestations of coronavirus disease (COVID-19) have increasingly been reported since the onset of the pandemic. Herein, we report a relatively new presentation. A patient in the convalescence period following a febrile illness with lower respiratory tract infection (fever, myalgia, nonproductive cough) presented with generalized disabling myoclonus, which is phenotypically suggestive of brainstem origin, along with additional truncal cerebellar ataxia. His neurology work-ups, such as brain MRI, electroencephalography, serum autoimmune and paraneoplastic antibody testing, were normal. His CT chest scan revealed right lower lung infiltrates, and serological and other laboratory testing did not show evidence of active infection. COVID-19 titers turned out to be strongly positive, suggestive of post-COVID-19 lung sequelae. He responded partially to antimyoclonic drugs and fully to a course of steroids, suggesting a para- or postinfectious immune-mediated pathophysiology. Myoclonusataxia syndrome appears to be a neurological manifestation of COVID-19 infection, and knowledge regarding this phenomenon should be increased among clinicians for better patient care in a pandemic situation.

Myoclonus-Ataxia Syndrome Associated with COVID-19

Neurological manifestations of coronavirus disease (COVID-19) have increasingly been reported since the onset of the pandemic. Herein, we report a relatively new presentation. A patient in the convalescence period following a febrile illness with lower respiratory tract infection (fever, myalgia, nonproductive cough) presented with generalized disabling myoclonus, which is phenotypically suggestive of brainstem origin, along with additional truncal cerebellar ataxia. His neurology work-ups, such as brain MRI, electroencephalography, serum autoimmune and paraneoplastic antibody testing, were normal. His CT chest scan revealed right lower lung infiltrates, and serological and other laboratory testing did not show evidence of active infection. COVID-19 titers turned out to be strongly positive, suggestive of post-COVID-19 lung sequelae. He responded partially to antimyoclonic drugs and fully to a course of steroids, suggesting a para- or postinfectious immune-mediated pathophysiology. Myoclonusataxia syndrome appears to be a neurological manifestation of COVID-19 infection, and knowledge regarding this phenomenon should be increased among clinicians for better patient care in a pandemic situation.

Safety and immunogenicity clinical trial of an inactivated SARS-CoV-2 vaccine, BBV152 (a phase 2, double-blind, randomised controlled trial) and the persistence of immune responses from a phase 1 follow-up report

BackgroundBBV152 is a whole-virion inactivated SARS-CoV-2 vaccine (3 {micro}g or 6 {micro}g) formulated with a Toll-like receptor 7/8 agonist molecule adsorbed to alum (Algel-IMDG). Earlier, we reported findings from a phase 1 (vaccination regimen on days 0 and 14) randomised, double-blind trial on the safety and immunogenicity of three different formulations of BBV152 and one control arm containing Algel (without antigen). Two formulations were selected for the phase 2 (days 0 and 28) study. Here, we report interim findings of a controlled, randomised, double-blind trial on the immunogenicity and safety of BBV152: 3 {micro}g and 6 {micro}g with Algel-IMDG. MethodsWe conducted a double-blind, randomised, multicentre, phase 2 clinical trial to evaluate the immunogenicity and safety of BBV152. A total of 380 healthy children and adults were randomised to receive two vaccine formulations (n=190 each) with 3 {micro}g with Algel-IMDG and 6 {micro}g with Algel-IMDG. Two intramuscular doses of vaccines were administered (four weeks apart). Participants, investigators, and laboratory staff were blinded to the treatment allocation. The primary outcome was seroconversion ([≥]4-fold above baseline) based on wild-type virus neutralisation (PRNT50). Secondary outcomes were reactogenicity and safety. Cell-mediated responses were evaluated. A follow-up blood draw was collected from phase 1 participants at day 104 (three months after the second dose). FindingsAmong 921 participants screened between Sep 7-13, 2020, 380 participants were randomised to the safety and immunogenicity population. The PRNT50 seroconversion rates of neutralising antibodies on day 56 were 92{middle dot}9% (88{middle dot}2, 96{middle dot}2) and 98{middle dot}3% (95{middle dot}1, 99{middle dot}6) in the 3 {micro}g and 6 {micro}g with Algel-IMDG groups, respectively. Higher neutralising titres (2-fold) were observed in the phase 2 study than in the phase 1 study (p<0.05). Both vaccine groups elicited more Th1 cytokines than Th2 cytokines. After two doses, the proportion (95% CI) of solicited local and systemic adverse reactions were 9.7% (6{middle dot}9, 13{middle dot}2) and 10.3% (7{middle dot}4, 13{middle dot}8) in the 3 {micro}g and 6 {micro}g with Algel-IMDG groups, respectively. No significant difference was observed between the groups. No serious adverse events were reported in this study. Phase 1 follow-up immunological samples at day 104 showed seroconversion in 73{middle dot}5% (63{middle dot}6, 81{middle dot}9), 81{middle dot}1% (71{middle dot}4, 88{middle dot}1), and 73{middle dot}1% (62{middle dot}9, 81{middle dot}8) of individuals in the 3 {micro}g with Algel-IMDG, 6 {micro}g with Algel-IMDG, and 6 {micro}g with Algel groups, respectively. InterpretationIn the phase 1 trial, BBV152 produced high levels of neutralising antibodies that remained elevated in all participants three months after the second vaccination. In the phase 2 trial, BBV152 led to tolerable safety outcomes and enhanced humoral and cell-mediated immune responses. The safety profile of BBV152 is noticeably lower than the rates for other SARS-CoV-2 vaccine platform candidates. The 6 {micro}g Algel-IMDG formulation was selected for the phase 3 efficacy trial. FundingThis work was supported and funded by Bharat Biotech International Limited. Clinicaltrials.gov: NCT04471519

Safety and immunogenicity trial of an inactivated SARS-CoV-2 vaccine-BBV152: a phase 1, double-blind, randomised control trial

BackgroundBBV152 is a whole-virion inactivated SARS-CoV-2 vaccine formulated with a TLR 7/8 agonist molecule adsorbed to alum (Algel-IMDG). MethodsWe conducted a double-blind randomized controlled phase 1 clinical trial to evaluate the safety and immunogenicity of BBV152. A total of 375 participants were randomized equally to receive three vaccine formulations (n=100 each) prepared with 3 g with Algel-IMDG, 6 g with Algel-IMDG, and 6 g with Algel, and an Algel only control arm (n=75). Vaccines were administered on a two-dose intramuscular accelerated schedule on day 0 (baseline) and day 14. The primary outcomes were reactogenicity and safety. The secondary outcomes were immunogenicity based on the anti-IgG S1 response (detected with an enzyme-linked immunosorbent assay [ELISA] and wild-type virus neutralization [microneutralization and plaque reduction neutralization assays]). Cell-mediated responses were also evaluated. ResultsReactogenicity was absent in the majority of participants, with mild events. The majority of adverse events were mild and were resolved. One serious adverse event was reported, which was found to be unrelated to vaccination. All three vaccine formulations resulted in robust immune responses comparable to a panel of convalescent serum. No significant differences were observed between the 3-g and 6-g Algel-IMDG groups. Neutralizing responses to homologous and heterologous SARS-CoV-2 strains were detected in all vaccinated individuals. Cell-mediated responses were biased to a Th-1 phenotype. ConclusionsBBV152 induced binding and neutralising antibody responses and with the inclusion of the Algel-IMDG adjuvant, this is the first inactivated SARS-CoV-2 vaccine that has been reported to induce a Th1-biased response. Vaccine induced neutralizing antibody titers were reported with two divergent SARS-CoV-2 strains. BBV152 is stored between 2{degrees}C and 8{degrees}C, which is compatible with all national immunization program cold chain requirements. Both Algel-IMDG formulations were selected for the phase 2 immunogenicity trials. Further efficacy trials are underway. Clinicaltrials.gov: NCT04471519

Total Synthesis of Macrocyclic Dysoxylactam A.

The total synthesis of dysoxylactam A, a novel 17-membered macrolactam with potent multi-drug-resistant reversing activities, has been achieved, starting from 4-pentene-1-al in a longest linear sequence of 17 steps and 9.5% overall yield. The key transformations consist of iterative aldol and ring-closing metathesis reactions for the construction of the stereochemically enriched polypropionate scaffold and the macrocycle, respectively.

Gas-solid interactions with reactive and inert gas molecules by NAPUPS: can work function be a better descriptor of chemical reactivity?

The gas-phase vibrational spectra of reactive (H2 and O2) and inert gases (N2 and Ar) have been studied by near-ambient pressure (NAP) ultraviolet photoelectron spectroscopy (NAPUPS) up to 0.3 mbar pressure. The results obtained are divided into two parts and discussed. In the first part, the photoelectron spectra of monoatomic Ar and some homonuclear diatomic molecules, such as H2, O2, and N2, have been recorded by NAPUPS and the effect of pressure on their energy position has been studied. It has been demonstrated that NAPUPS could be an essential tool to determine the intermolecular or interatomic interactions. In the second part, we have evaluated the influence of different solid surfaces on the binding energy (BE) position, the pattern of the vibrational features of diatomic N2 molecules, and the first atomic levels (3p3/2 and 3p1/2) of monoatomic Ar. It has been observed that with a change in the (electronic/chemical) nature of the surface, the BE of the above features also changes and reflects the change in the work function (φ) of the material. It is to be noted that Ar is an inert/noble gas and N2 is the most stable molecule, and the above changes observed underscore that they can be employed as probe atoms/molecules to explore even the minor changes that occur on a solid surface due to a variety of reasons. Further, if the solid surface undergoes any chemical/electronic changes due to gas-solid interaction, such as oxidation/reduction, the φ of the surface changes again; this highlights the precise identification of the changes that occur under the reaction/measurement conditions. Therefore, the change in the BE of the gas-phase features can be used to determine even the minor changes in the φ of solid surfaces during the reaction or due to the reaction. The present findings have implications in probing the surface changes that occur in any surface-dependent phenomena, such as heterogeneous catalysis, electrochemistry, and materials that are predominantly controlled by surface contribution, such as layered (2D) materials, nanomaterials.

Organocatalytic umpolung annulative dimerization of ynones for the synthesis of 5-alkylidene-2-cyclopentenones.

A novel phosphine-catalyzed umpolung [3 + 2]-annulative dimerization of ynones was developed to furnish functionally rich 5-alkylidene-2-cyclopentenones. In this protocol, ynone acts as both C2 and C3 synthons, which undergo [3 + 2]-annulative dimerization.

Total Synthesis of Kanamienamide.

Kanamienamide is a novel enol ether containing enamide with a single digit micromolar inhibitory activity against cancer cell lines. An efficient and convergent total synthesis of kanamienamide has been developed for the first time, which features a Cu-mediated amide coupling with vinyl iodide at the late stage. Other key transformations include Evans asymmetric alkylation, CBS asymmetric reduction, ring-closing metathesis reaction, and Stork-Zhao-Wittig olefination. This strategy is amenable for facile analogue preparation and SAR studies.

A Unified Modular Synthetic Strategy for Dictyodendrins F, H, I, and G.

A unified modular synthetic strategy has been developed for the first total synthesis of dictyodendrins G and synthesis of dictyodendrin F, H and I in 11 steps. The synthesis features consecutive functionalization of the core aminoquinone by palladium-mediated Suzuki-Miyaura coupling reaction, 1,4-addition, acylation and base mediated formation of a pyrrolinone, and the formation of carbazolequinone moiety through a formal [3 + 2] cycloaddition using arynes generated in situ. Several dictyodendrin analogues were also synthesized using this strategy.

Surgical revascularization for premature coronary artery disease in second and third decade of life.

Coronary artery bypass grafting surgery may be needed in children and young adults for significant premature coronary artery occlusive disease. We report a case series of seven patients who underwent surgical revascularization in their second and third decade of life for significant multivessel coronary artery occlusive disease due to unusual causes.

Organocatalytic azomethine imine-olefin click reaction: high-yielding stereoselective synthesis of spiroindane-1,3-dione-pyrazolidinones.

In search of developing new useful "click reactions", herein we report the organocatalytic azomethine imine-olefin [3 + 2]-cycloaddition as a new click reaction for the synthesis of drug-like spiroindane-1,3-dione-pyrazolidinones from indane-1,3-diones, aldehydes and N,N-cyclic azomethine imines through amino acid-catalysis. The scope of this new click reaction is demonstrated using many examples with high reactivity, selectivity and yields.

Rawal's catalyst as an effective stimulant for the highly asymmetric Michael addition of ß-keto esters to functionally rich nitro-olefins.

A general approach to asymmetric synthesis of highly substituted dihydroquinolines was achieved through neighboring ortho-amino group engaged sequential Michael/amination/dehydration reactions on (E)-2-(2-nitrovinyl)anilines with cyclic and acyclic ß-keto esters in the presence of a catalytic amount of Rawal's quinidine-NH-benzyl squaramide followed by TFA.

A pH-triggered delayed-release chronotherapeutic drug delivery system of aceclofenac for effective management of early morning symptoms of rheumatoid arthritis.

CONTEXT: Rheumatoid arthritis (RA) is differentiated as an early morning exacerbation of the core arthritis condition associated with increase in pain and stiffness in joints and necessitate for medication. OBJECTIVE: The aim of the present work was to develop and optimise a pH-triggered delayed-release colon-specific aceclofenac microspheres and to accomplish chronotherapy of RA. METHODS: A 3-factor, 3-level Box-Behnken design (BBD) was used to optimise selected variables. Developed formulation was evaluated for in vivo delayed response and anti-arthritis activity in rats. RESULTS: The particle size and encapsulation efficacy of these microspheres were 117.36 ± 10.54 µm and 85.06 ± 5.85%, respectively. Optimised formulation was analysed by SEM, DSC, X-RPD and FTIR. The in vivo evaluation revealed delayed anti-inflammatory activity in carrageenan-induced rats and anti-arthritic activity in freund's adjuvant-induced arthritis rats. CONCLUSION: The optimised aceclofenac microspheres formulation is potential for the chronotherapy of early morning symptoms of RA.

Pharmacokinetics of colon-specific pH and time-dependent flurbiprofen tablets.

Present research deals with the development of compression-coated flurbiprofen colon-targeted tablets to retard the drug release in the upper gastro intestinal system, but progressively release the drug in the colon. Flurbiprofen core tablets were prepared by direct compression method and were compression coated using sodium alginate and Eudragit S100. The formulation is optimized based on the in vitro drug release study and further evaluated by X-ray imaging and pharmacokinetic studies in healthy humans for colonic delivery. The optimized formulation showed negligible drug release (4.33 ± 0.06 %) in the initial lag period followed by progressive release (100.78 ± 0.64 %) for 24 h. The X-ray imaging in human volunteers showed that the tablets reached the colon without disintegrating in the upper gastrointestinal tract. The C max of colon-targeted tablets was 12,374.67 ng/ml at T max 10 h, where as in case of immediate release tablets the C max was 15,677.52 ng/ml at T max 3 h, that signifies the ability of compression-coated tablets to target the colon. Development of compression-coated tablets using combination of time-dependent and pH-sensitive approaches was suitable to target the flurbiprofen to colon.

Novel orally available salvinorin A analog PR-38 protects against experimental colitis and reduces abdominal pain in mice by interaction with opioid and cannabinoid receptors.

BACKGROUND: Salvinorin A (SA) is a potent anti-inflammatory diterpene isolated from the Mexican plant S. divinorum. Recently we showed that the novel SA analog, PR-38 has an inhibitory effect on mouse gastrointestinal (GI) motility mediated by opioid and cannabinoid (CB) receptors. The aim of the study was to characterize possible anti-inflammatory and antinociceptive action of PR-38 in the mouse GI tract. METHODS: Macro- and microscopic colonic damage scores and myeloperoxidase activity were determined after intraperitoneal (i.p.), intracolonic (i.c.), and per os (p.o.) administration of PR-38 in the trinitrobenzene sulfonic acid (TNBS) and dextran sodium sulfate (DSS) models of colitis in mice. Additionally, MOP, KOP and CB1 protein expression was determined using Western blot analysis of mouse colon samples. The antinociceptive effect of PR-38 was examined based on the number of behavioral responses to i.c. instillation of mustard oil (MO). RESULTS: The i.p. (10 mg/kg, twice daily), i.c. (10 mg/kg, twice daily) and p.o. (20 mg/kg, once daily) administration of PR-38 significantly attenuated TNBS- and DSS-induced colitis in mice. The effect of PR-38 was partially blocked by the KOP antagonist nor-binaltorphimine and CB1 antagonist AM 251. Western blot analysis showed a significant increase of MOP, KOP and CB1 receptor expression during colonic inflammation, which was reversed to the control levels by the administration of PR-38. PR-38 significantly decreased the number of pain responses after i.c. instillation of MO in the TNBS-treated mice. CONCLUSIONS: Our results suggest that PR-38 has the potential to become a valuable anti-inflammatory and analgesic therapeutic for the treatment of GI inflammation.